https://orcid.org/0009-0005-1637-4394
Figures
Abstract
Background
The literature has proven that plyometric training (PT) improves various physical performance outcomes in sports. Even though PT is one of the most often employed strength training methods, a thorough analysis of PT and how it affects technical skill performance in sports needs to be improved.
Methods
This study aimed to compile and synthesize the existing studies on the effects of PT on healthy athletes’ technical skill performance. A comprehensive search of SCOPUS, PubMed, Web of Science Core Collection, and SPORTDiscus databases was performed on 3rd May 2023. PICOS was employed to establish the inclusion criteria: 1) healthy athletes; 2) a PT program; 3) compared a plyometric intervention to an active control group; 4) tested at least one measure of athletes’ technical skill performance; and 5) randomized control designs. The methodological quality of each individual study was evaluated using the PEDro scale. The random-effects model was used to compute the meta-analyses. Subgroup analyses were performed (participant age, gender, PT length, session duration, frequency, and number of sessions). Certainty or confidence in the body of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE).
Results
Thirty-two moderate-high-quality studies involving 1078 athletes aged 10–40 years met the inclusion criteria. The PT intervention lasted for 4 to 16 weeks, with one to three exercise sessions per week. Small-to-moderate effect sizes were found for performance of throwing velocity (i.e., handball, baseball, water polo) (ES = 0.78; p < 0.001), kicking velocity and distance (i.e., soccer) (ES = 0.37–0.44; all p < 0.005), and speed dribbling (i.e., handball, basketball, soccer) (ES = 0.85; p = 0.014), while no significant effects on stride rate (i.e., running) were noted (ES = 0.32; p = 0.137). Sub-analyses of moderator factors included 16 data sets. Only training length significantly modulated PT effects on throwing velocity (> 7 weeks, ES = 1.05; ≤ 7 weeks, ES = 0.29; p = 0.011). The level of certainty of the evidence for the meta-analyzed outcomes ranged from low to moderate.
Conclusion
Our findings have shown that PT can be effective in enhancing technical skills measures in youth and adult athletes. Sub-group analyses suggest that PT longer (> 7 weeks) lengths appear to be more effective for improving throwing velocity. However, to fully determine the effectiveness of PT in improving sport-specific technical skill outcomes and ultimately enhancing competition performance, further high-quality research covering a wider range of sports is required.
Citation: Deng N, Soh KG, Abdullah B, Huang D, Xiao W, Liu H (2023) Effects of plyometric training on technical skill performance among athletes: A systematic review and meta-analysis. PLoS ONE 18(7): e0288340. https://doi.org/10.1371/journal.pone.0288340
Editor: Bojan Masanovic, University of Montenegro, MONTENEGRO
Received: March 27, 2023; Accepted: June 25, 2023; Published: July 17, 2023
Copyright: © 2023 Deng et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the manuscript and its Supporting Information files.
Funding: The authors received no specific funding for this work.
Competing interests: The authors have declared that no competing interests exist.
Introduction
Achievement in sports is generally ascribed to a unique blend of talented and trained physical, technical, tactical, and psychological skills [1]. Evaluating these complex facets may provide valuable information for coaches and trainers regarding the requirements of a particular game or sport and help pinpoint specific aspects that players could improve upon to enhance their performance [2]. Among these factors, a definite correlation exists between technical skills and sports achievement [3]. Sport-specific technical skills refer to actions that involve a specific objective or goal and require the coordination of several motor abilities in a particular context and time frame [4]. Examples of these skills could include passing a soccer ball to a teammate to advance the ball, or throwing a baseball to get an opponent out [2]. The outcome of numerous sports games can be significantly affected by the technical skill level of the participants [3]. For example, in tennis, the serve is regarded as the most crucial technical skill since it can help a player gain an advantage in a point or even secure a direct win [5]. Moreover, it is well known that strength training is commonly associated with performance improvements [6]. Therefore, good training practices to enhance players’ technical skills are essential to optimize their performance during matches.
Most coaches and athletes competing at the top levels recognize the value of maintaining and constantly improving technical skill performance [7]. Therefore, an extensive amount of research has been conducted on the development of technical skills employing multiple types of workouts, such as resistance training [8], core training [9], conditioning training [10], and plyometric training (PT) [11]. Notably, PT is a type of strength training that mainly consists of various jumping, hopping, skipping, and throwing exercises [12]. These exercises are inherent in most sports movements, such as high jumping, pitching, or kicking [13, 14]. This method appears to be prevalent [15–18] or even more effective [19, 20] than other training methods (e.g., conventional resistance exercises). The defining feature of PT is the utilization of the stretch-shortening cycle (SSC), which occurs as the muscle rapidly transitions from an eccentric contraction (deceleration phase) to a concentric contraction (acceleration phase) [21]. During SSC tasks, the elastic properties of the muscle and connective tissue are leveraged to store elastic energy during the deceleration phase and release it during the acceleration phase, thus improving the force and power output of the muscle [22, 23]. Plyometrics help build power, a crucial foundation for athletes to improve their sport-specific skills by capitalizing on the SSC [12]. Moreover, to ensure maximum transfer to sport, the plyometric exercises included in a training program should align with the individual requirements of the athlete and the characteristics of the sport [24]. In other words, the principle of specificity should be followed by selecting plyometric exercises that reflect the type of activity involved in the sport [24]. For instance, some researchers [25, 26] have stated that jumping exercises like vertical jumps were considered irrelevant to improving running performance and therefore did not impact running speed. However, when exercises were designed specifically for running, such as speed bounding, the training program produced a favorable effect on running velocity [27, 28]. Similarly, sprint performance improvements will be optimized by using training regimens that contain greater horizontal acceleration (i.e., jumps with horizontal displacement; sprint-specific plyometric exercises) [24, 29].
Previous reviews and studies have extensively discussed the potential mechanisms (i.e., mechanical and neurophysiological models) implicated in the SSC and its capacity for enhancing human performance [17, 22, 30–33]. The potential benefits and theoretical training improvements associated with plyometric exercises for the upper and lower limbs include, but are not limited to, the following: (a) elevating peak force and acceleration velocity; (b) increasing time for force production; (c) storing energy in the elastic components; (d) increasing muscle activation levels; (e) evoking stretch reflexes [12, 23, 34]. Furthermore, proprioceptors such as the Golgi tendon organ are believed to play a role in a defensive inhibitory reflex response that can be improved through PT. This reflex may elevate performance during activities that involve high-load situations [34, 35]. These adaptations are associated with improvements in several physical qualities, such as strength [36], power [37], agility [38], sprint speed [24], and balance [39]. Indeed, excellent physical ability allows athletes to effortlessly and efficiently execute skills at a high level [40]. For example, to perform gymnastics routines such as vault and tumbling with optimal control and efficiency, gymnasts need to have well-developed explosive power in their upper and lower body muscles [41]. According to Lambrich and Muehlbauer [42], developing optimal agility is crucial for executing tennis-specific footwork and achieving a robust tennis stroke performance. Consequently, in light of the theories mentioned above and the observable improvements in physical characteristics after PT, it seems reasonable to hypothesize that PT could benefit athletes’ technical skill performance, regardless of their training backgrounds.
To the best of the authors’ knowledge, only one systematic review published in the literature focuses solely on PT’s impact on tennis players’ technical skill performance [11]. Most reviews focused on the physical fitness aspects of athletes [16, 43, 44]. Additionally, in a previous investigation conducted on soccer players [45], the analysis of technical skill performance as part of physical performance provided a superficial knowledge of the topic and needed to be revised to make significant conclusions. Based on existing reviews, the effects of PT on athletes’ technical skill performance still require further clarification. Likewise, a growing number of experimental studies investigated the effects of PT on sports-specific technical skills among athletes. For example, Guadie [46] discovered that PT improves handball team players’ technical skill performance in shooting accuracy and speed dribbling. However, this evidence needs to be compiled systematically. Conducting a systematic review with meta-analysis may aid in pinpointing inadequacies and shortcomings in the PT literature and offer practitioners or scholars in related fields valuable insights about prospective future research directions [47]. Therefore, the primary purpose of this systematic review and meta-analysis is to analyze the evidence published about the effects of PT on athletes’ technical skill performance and, thus, to expand the current understanding of its effects on athletic populations. For this purpose, this study reviewed experimental trials that compared PT to a comparison group of athletes. All the selected studies met the RCT criteria.
Methodology
Protocol and registration
The PRISMA statement [48] was followed in reporting this systematic review and meta-analysis, and the review protocol has been registered on Inplasy.com (INPLASY202320052).
Eligibility criteria
A PICOS framework [49] was used to rate studies for eligibility. The criteria include the following:
- Population: The participants were healthy female and male athletes of any age and competition level (no restriction).
- Intervention: The minimum PT intervention duration was four weeks. Plyometric exercise programs can focus on either the upper or lower limbs or a combination. These exercises may include medicine ball exercises, plyometric push-ups, bilateral or unilateral bounds, hops, jumps, and skips. These exercises typically involve a pre-stretch or countermovement that stresses the SSC. PT combined with other types of strength training (e.g., weight training) was excluded to avoid confounding effects [37]; however, trials that included combined training were included if it was specified that the control group received the same training as the experimental group, except for the PT component.
- Control: The control group was in a regular sports program without plyometric exercises.
- Outcomes: The study’s results need to include the effect of at least one plyometric exercise on the technical skill performance of participants. A technical skill outcome was defined as actions that involve a specific task or goal and require the coordination of several motor abilities in a particular context and time frame [4]. To be eligible for inclusion, studies needed to report the treatment effect or pre- and post-test values for technical skill outcomes specific to the sport. Studies that solely assessed time trial performance outcomes (e.g., running) rather than sport-specific technical skills (e.g., stride frequency) were not considered.
- Study design: This review considered randomized controlled trials.
Furthermore, studies that did not meet the inclusion criteria were rejected from this review.
Search strategy and selection process
On the 3rd of May 2023, the following four electronic databases were searched to obtain articles pertinent to the topic: Web of Science Core Collection, SPORTDiscus, PubMed, and SCOPUS. Previous reviews [50, 51] were used to help define our search strategy; keywords and Boolean operators were considered separately and in aggregation while searching the four databases (S1 Table). This study employed the following terms and operators: ("plyometric training" OR "plyometric exercise*" OR "stretch-shortening cycle" OR "jump training") AND (“athletic performance” OR “technical skill*” OR “skill*” OR “technique” OR “performance”) AND (athlete* OR player*). Moreover, to find studies that could potentially be incorporated into this systematic review, we scrutinized pertinent review articles that were published prior to May 3, 2023 [11, 45, 47, 52, 53]. Furthermore, relevant supplementary material was searched for through manual searches on Google Scholar, including article citations and free-text searches. In addition, we screened the reference lists of all the identified articles to discover any publications that were not detected by the initial computerized search. Finally, experienced librarians backed up the data-gathering process and ensured that the process was performed correctly.
The study selection included four significant processes (Fig 1). Initially, duplicate articles were eliminated, and the title and abstract were determined in the second stage. Studies were excluded if they dealt with different subjects or were written in a language other than English. The review only included articles written in English because articles written in other languages can be challenging to translate. Moreover, almost all of the literature (99.6%) on plyometric jump training is published in English [54]. Conference abstracts, books, book sections, pilot studies, or papers not published in peer-review journals were excluded. The full-text screening process included a review of predetermined eligibility criteria. Furthermore, studies were excluded if they inadequately reported PT, if testing protocols for technical skill performance measurements were not conducted under supervision, if the entire text was unavailable from the database or the authors. Two independent reviewers (ND and DH) completed this process. Any dispute was further explored. If necessary, a third reviewer (KGS) helped until an agreement was obtained.
Data extraction
Two reviewers (ND and DH) obtained information about each study by utilizing a Microsoft Excel spreadsheet (Microsoft Corporation, Redmond, WA, United States), and a third reviewer (KGS) verified its accuracy. The records taken into account were: a) name of the first author, year, and country of publication; b) subject characteristics: age, sex, sample size, competition level, and sports experience; and c) characteristics of the PT intervention, which include training length, frequency, time, type of exercise, PT replaced (if applicable) a component of the regular practice; d) assessment of technical skill performance: several measures of technical skills were selected after discussions among the co-authors, including, but not limited to: kicking (e.g., soccer), dribbling (e.g., handball), passing (e.g., basketball), serving (e.g., tennis); e) mean and standard deviation of the results for PT and control groups.
Study quality assessment
Two authors (ND, KGS) independently utilized the PEDro scale, which is a valid [55] and reliable [56] instrument for grading the methodological quality of investigations. The results were cross-checked by the third author (AB) and all three reviewers achieved agreement. On a scale of 1 to 10, ≤ 3 points indicated poor quality, 4–5 points indicated moderate quality, and 6–10 points indicated high quality. The PEDro scale comprises 11 elements used to evaluate methodological quality. Each fulfilled item provides one point to the total PEDro score (0–10 points). Regarding external validity, criterion 1 was excluded from the research quality evaluation. To decrease the possibility of a high risk of bias in the analysis, it was decided after the fact to exclude studies that were rated with a score of 3 or lower. A discussion with a third reviewer (BA) resolved disagreements between the two reviewers.
Certainty of evidence
The certainty of the evidence was evaluated by two authors (ND and DH) using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology, which categorized it as very low, low, moderate, or high [57–59]. The evidence was initially rated as high for each outcome, but was later downgraded after evaluating the following criteria: (a) risk of bias in studies: if the median PEDro scores were moderate (less than 6), the judgments were lowered by one level; (b) indirectness: low risk of indirectness was ascribed by default owing to the specificity of populations, interventions, comparators, and outcomes being ensured by the inclusion/exclusion criteria; (c) risk of publication bias: downgraded by one level if there was suspected publication bias; (d) inconsistency: judgments were downgraded by one level when the impact of statistical heterogeneity (I2) was high (> 75%); (e) imprecision: one level of downgrading occurred whenever < 800 participants were available for a comparison [60] and/or if the effects’ direction was unclear. When both were observed, certainty was downgraded by two levels. If the number of comparison trials was insufficient to conduct a meta-analysis, the evidence was automatically considered of very low certainty [47]. Therefore, for the outcomes not included in the meta-analyses, the certainty of evidence should be regarded as very low.
Statistical analysis
Although a meta-analytical comparison can be made with just two studies [61], the field of PT often has small sample sizes [47]. Therefore, we only conducted meta-analyses when three or more studies reported data on the technical skill outcomes mentioned earlier [11]. To calculate effect sizes (ES) (Hedges’ g), means and standard deviations of a measure of pre-post-intervention performance were utilized, and the data were standardized using the post-intervention data of a relevant performance measure. If data values were not accessible, such as when they were omitted or displayed in graphical form, the corresponding author of the study was contacted to obtain the necessary information. In cases where data were presented graphically without numerical data, validated (r = 0.99, p < 0.001) [62] software (WebPlot- Digitizer, version 4.5; https://apps.automeris.io/wpd/) was employed to extract the numerical data from the figures.
The meta-analyses employed the inverse variance random-effects model, which assigns weights to trials proportional to their individual standard errors [63], and facilitates analysis while accounting for heterogeneity across studies [64]. The ESs were presented with 95% confidence intervals (95% CIs), and standardized mean differences were used to interpret the calculated ESs, with conventions as follows: <0.2, trivial; 0.2–0.6, small; >0.6–1.2, moderate; >1.2–2.0, large; >2.0–4.0, very large; >4.0, extremely large [65]. In studies with multiple intervention groups, the control group was proportionally divided to enable comparison across all participants [66]. The I2 statistics were used to assess the impact of study heterogeneity, with values of <25%, 25–75%, and >75% indicating low, moderate, and high levels of heterogeneity, respectively [67]. The extended Egger’s test was used to investigate the risk of publication bias [68], and a sensitivity analysis was performed in the case of a significant Egger’s test. All analyses were performed using the Comprehensive Meta-Analysis program (version 3; Biostat, Englewood, NJ, USA), with a statistical significance threshold of p < 0.05.
Additional analysis
Subgroup analyses were conducted to examine the potential impact of moderator factors. Relevant sources of heterogeneity that could affect the training effects were pre-selected based on the authors’ discussion and study characteristics: program length (weeks), training frequency (sessions per week), the total number of training sessions, and weekly session time. Participants were divided using a median split [30, 69] for training length (i.e., ≤ 7 vs. > 7 weeks), the total number of PT sessions (i.e., ≤ 14 vs. > 14 sessions), and the time of PT session itself (main part) (i.e., ≤ 30 vs. > 30 minutes). As the majority of studies utilized a training frequency of 2 or 3 sessions per week (see Table 3), we grouped the training frequency as either 2 or 3 sessions per week to facilitate comparison. For each moderator factor, the median was computed if there were at least three studies providing data. Additionally, we examined the gender (male vs. female) and age (< 18 years of age vs. ≥ 18 years of age) of the athletes as potential moderator factors.
Results
Study selection
Fig 1 illustrates that a total of 2501 papers were initially found through searches on databases. An additional 45 studies were identified through Google Scholar and reference lists. After manually removing duplicates, 1225 records remained. The titles and abstracts of the 1225 records were checked. After screening the titles and abstracts of articles, 338 papers were identified as potentially eligible for full-text analysis. However, after conducting a full-text examination, 306 publications were excluded. Ultimately, 32 papers met the inclusion criteria and 30 of those were eligible for meta-analysis.
Study quality assessment
The PEDro checklist was used to assess each paper’s quality, and the results showed that seven studies received a score of 4 or 5, indicating a moderate quality. Meanwhile, 25 studies scored 6 to 9 points, considered highly methodological. However, a study [70] with a quality score of ≤ 3 points was noted and thus excluded from this review (Table 1).
Certainty of evidence
Table 2 presents the GRADE analyses, which indicate that the certainty of the evidence was low to moderate for all outcomes and group comparisons. In addition, for comparisons that were not analyzed using meta-analysis, the evidence was suggested to be of very low certainty.
Study characteristics
Table 3 displays the participant and intervention characteristics of the RCTs included in this review. All research that satisfied the criteria for inclusion was released in English from 2006 to 2023. Out of the 32 articles analyzed, 21 were two-armed trials [46, 71–75, 77–79, 81, 82, 86, 88–90, 93, 94, 97–100], four were three-armed [19, 87, 91, 95], and the remaining four had four arms [76, 80, 83, 84]. Thirteen RCTs were conducted in America (ten in Chile, one in Brazil, and two in the United States) [72, 76, 79, 80, 83–85, 90–92, 94–96], eleven in Europe (three in Spain, one in Ethiopia, one in Germany, one in Greece, one in France, one in Italy, one in Turkey, and two in the United Kingdom) [19, 46, 73, 78, 86–89, 93, 98, 99]. Two RCTs were conducted in Asia (one in Malaysia; one in India) [77, 100], three took place in Africa (two in Tunisia, one in Ethiopia) [46, 97, 81], and one in Oceania (Australia) [71].
Out of the 32 documents, sixteen focused on soccer players [74, 75, 78–80, 83–85, 91, 92, 94–96, 99–100]; four articles on handball players [46, 81, 97, 98]; three articles on runners [71, 89, 90]; three articles on water polo players [82, 86, 87]; two studies on baseball players [72, 76]; and the remaining four articles were on swimmers [73], basketball players [77], gymnasts [88], tennis players [19]. There were 1078 participants in total, with 644 men (59.7%) and 84 women (7.8%), while 350 (32.5%) did not report gender or mixed gender. The mean age of the participants ranged from 10 to 40 years old. In terms of athletes’ expertise level, eight studies employed regional or local sport club athletes; ten studies were categorized as national players. Three studies recruited university or college players, two studies selected high school or youth soccer school athletes, and two studies recruited amateur or recreational athletes. However, seven studies did not report participant levels. In addition, 12 studies reported between two months and eight years of specific-sport experience, whereas ten studies did not report the duration of participants’ sport-specific experience.
Different PT modes were employed in the experimental groups, most of which were lower limb plyometric exercises (n = 21). Four studies used upper limb plyometric training, and seven studies employed combined upper and lower limb plyometric training exercises. The average length of PT was 7.9 weeks, with a range of 4 to 16 weeks, and the average frequency per week was 2.4 sessions, ranging from 1 to 3 sessions. Out of the included studies, 14 reported session durations between 10 and 30 minutes, and 11 reported between 30 and 60 minutes. Seven papers did not provide information on the duration of the sessions.
Meta-analysis results
The meta-analysis focused on 30 studies that evaluated athletes’ technical skills, specifically measuring kicking velocity and distance (in soccer), throwing velocity (in handball, baseball, and tennis), dribbling speed (in soccer and handball), and stride rate (in running). The data used for the meta-analyses can be found in S2 Table.
Six studies provided data for throwing velocity, involving nine experimental and six control groups (pooled n = 270). Results showed a moderate effect of PT on kicking velocity (ES = 0.78; 95% CI = 0.49–1.07; p < 0.001; I2 = 8.7%; Egger’s test p = 0.15; Fig 2). The weight value of every study ranged from 8.94 to 14.88% in the analysis.
Values shown are effect sizes (Hedges’s g) with 95% confidence intervals (CI). The size of the plotted squares reflects the statistical weight of the study.
Eight studies provided data for kicking velocity, involving 15 experimental and eight control groups (pooled n = 267). The Egger’ s test revealed a p = 0.008. After sensitivity analysis, the removal of one study [74] allowed an Egger’s test p > 0.05. As such, 14 studies with seven experimental and three control groups were finally considered. There was a small effect of PT on kicking velocity performance (ES = 0.37; 95% CI = 0.08–0.65; p = 0.011; I2 = 0.0%; Egger’s test p = 0.072; Fig 3). The weight value of every study ranged from 5.21 to 11.55% in the analysis.
Values shown are effect sizes (Hedges’s g) with 95% confidence intervals (CI). The size of the plotted squares reflects the statistical weight of the study.
Six studies provided data for kicking distance, involving ten experimental and six control groups (pooled n = 363). Results showed a small effect of PT on kicking distance (ES = 0.44; 95% CI = 0.23–0.65; p < 0.001; I2 = 0.0%; Egger’s test p = 0.970; Fig 4). The weight value of every study ranged from 3.81 to 22.18% in the analysis.
Values shown are effect sizes (Hedges’s g) with 95% confidence intervals (CI). The size of the plotted squares reflects the statistical weight of the study.
Three studies provided data for speed dribbling, involving three experimental and three control groups (pooled n = 87). Results showed a moderate effect of PT on speed dribbling (ES = 0.85; 95% CI = -0.17–1.52; p = 0.014; I2 = 57.6%; Egger’s test p = 0.799; Fig 5). The weight value of every study ranged from 25.40 to 42.03% in the analysis.
Values shown are effect sizes (Hedges’s g) with 95% confidence intervals (CI). The size of the plotted squares reflects the statistical weight of the study.
Four studies provided data for stride rate performance, involving four experimental and four control groups (pooled n = 91). Results showed a small effect of PT on kicking velocity (ES = 0.32; 95% CI = -0.10–0.73; p = 0.137; I2 = 0.0%; Egger’s test p = 0.393; Fig 6). The weight value of every study ranged from 19.08 to 29.82% in the analysis.
Values shown are effect sizes (Hedges’s g) with 95% confidence intervals (CI). The size of the plotted squares reflects the statistical weight of the study.
Additional analysis
Due to a restricted number of trials (three per moderator), only 16 analyses of moderators were performed (as shown below).
Regarding subject-related moderator variables, when compared to younger athletes, no significant increases were observed following PT in their older counterparts, for kicking velocity (<18 years of age, ES = 0.29; ≥ 18 years of age, ES = 0.52; p = 0.449), and throwing velocity (<18 years of age, ES = 0.69; ≥ 18 years of age, ES = 0.86; p = 0.587).
Regarding training-related moderator variables, significantly greater improvements in throwing velocity were observed after a period of PT lasting > 7 weeks compared to those lasting ≤ 7 weeks (> 7 weeks, ES = 1.05; ≤ 7 weeks, ES = 0.29; p = 0.011). However, no significant improvements were observed following PT when athletes performed > 7 weeks, as opposed to when they performed ≤ 7 weeks, for kicking velocity (> 7 weeks, ES = 0.50; ≤ 7 weeks, ES = 0.29; p = 0.501). Moreover, no significant improvements were noted following PT when athletes performed >14 total PT sessions, as opposed to when they performed ≤ 14 total PT sessions, for kicking velocity (> 14 total PT sessions, ES = 0.51; ≤ 14 total PT sessions, ES = 0.30; p = 0.506). Furthermore, no significant subgroup difference was found when comparing PT interventions with 2 sessions per week to those with 3 sessions per week for throwing velocity (2 sessions, ES = 0.99; 3 sessions, ES = 0.50; p = 0.106). In addition, no significant subgroup differences were identified between sessions lasting > 30 minutes and those lasting ≤ 30 minutes (> 30 minutes, ES = 0.26; ≤ 30 minutes, ES = 0.40; p = 0.690), and throwing velocity (> 30 minutes, ES = 0.53; ≤ 30 minutes, ES = 1.11; p = 0.061).
Discussion
This systematic review and meta-analysis aimed to investigate the impact of PT on technical skill performance among athletes. The final analysis included 30 studies that were eligible for inclusion based on the selection criteria. The main finding of this study indicates that PT interventions induced small-to-moderate improvements (ES = 0.67 to 1.47) in kicking velocity and distance, throwing velocity, and speed dribbling, while a non-significant small improvement in stride rate was noted. Mostly, the level of heterogeneity in the above-mentioned results was low-to-moderate (I2 = 0.0–57.6%). This finding aligns with previous reviews [101–103] that supported the efficacy of PT in enhancing athletic performance in athletes.
The effect of PT on throwing velocity
Numerous sports and work-related tasks necessitate forceful movements involving the arms and hands [104]. In the current review, nine studies were included which examined the impact of PT on ball-throwing velocity in various sports. The participants of these studies included baseball players [72, 76], water polo players [82, 86, 87], handball players [81, 97, 98], and tennis players [19]. Our meta-analysis revealed moderate (ES = 0.78) PT-related improvements in measures of throwing velocity compared to active controls. Indeed, most (7 out of 9) of the included studies in the meta-analysis incorporated upper-body PT drills. These results concur with Singla et al.’s findings [105], which summarized the effects of upper-body PT in improving ball-throwing distance and velocity in healthy individuals. Upper-body PT utilizes medicine ball exercises and plyometric push-ups to enhance players’ throwing muscles [106, 107]. Previous research has indicated that medicine ball exercises can lead to significant improvements in the upper body strength and power variables, particularly in the shoulder muscles, as well as rotational strength of the trunk and hip muscles in handball [108] and baseball players [109]. Internal and external rotator muscles, especially in the shoulders, are essential in ball speed [110]. Moreover, this exercise requires coordinating the agonist and antagonist muscles to maintain a rhythmic plyometric motion by incorporating a high-intensity concentric contraction right after an eccentric contraction [111]. Consequently, the nervous system is trained to respond faster [112]. Previously, overhead-throwing athletes were advised to follow the ballistic six exercise regimen [113, 114]. In a study by Carter et al. [72], when compared to the CG, baseball players that participated in an upper limb PT program employing six ballistic exercises increased throwing velocity. To simulate the actions, positions, and forces associated with the overhead throwing motion, the ballistic six-upper limb PT protocol includes a series of functional exercises carried out at high volumes [72]. In other words, to utilize the stretch reflex, plyometric exercises performed ballistic and explosive to reduce the amortization phase of the SSC. The results are reinforced by the findings of Grezios et al. [115], who showed that the SSC, which is the fundamental principle of PT, is the dominant type of muscle contraction used in overhead throwing. Interestingly, one study in this review reported that upper body PT could improve handball throwing speed, but no notable difference was detected between EG and CG. A similar duration of routine handball training also positively affects throwing speed [98]. Future research could explore the optimal combination of PT and handball training to maximize the benefits. Moreover, Chelly and colleagues [81] emphasized the importance of lower limb strength and power for throwing ability, suggesting that coaches should incorporate training programs for not only the upper body, but also the lower limbs. For example, water polo players’ throwing speed is influenced by multiple factors, including throwing technique, upper-body, lower-body, and trunk strength, and vertical jumping ability [116–118]. In agreement, two studies reviewed in this paper showed that either a combined upper and lower limb PT program or a lower limb PT program resulted in significant improvements in water polo players’ overhead throwing velocity [86, 87]. The strong correlation between force and throwing velocity provides evidence that lower-body force can also influence the ability to generate throwing velocity by improving the capacity to push the body out of the water [119]. Additionally, in tennis, the serve can be compared to a throwing motion, and coaches often use throwing skills to train players to improve their serve [120]. Research suggests that exercises mimicking throwing actions with a SSC are more effective than isokinetic exercises for improving serve performance [121, 122]. Baiget et al. [123] suggest that upper-body plyometric exercises are effective for improving serve performance as they involve multiple body structures and can generate high force in short periods of time, which is essential for a fast serve. To achieve the best results, these exercises should be performed in a full range of motion, with high-velocity rotations, and involving multiple joints, particularly around the shoulder complex [123].
The effect of PT on kicking velocity and distance
Several researchers have emphasized that kicking is critical in soccer [124–126]. Our meta-analysis noted that PT could help soccer players improve their technical skill performance in kicking velocity (ES = 0.37) [74, 75, 83–85, 91, 95, 100] and distance (ES = 0.44) [78–80, 92, 94, 96]. The effectiveness of a kick depends on various factors such as the maximum strength of the muscles involved [127, 128], the coordination between the nervous system and muscles, and the velocity at which the ankle moves both linearly and angularly in the kicking leg [129]. Markovic [130] stated in meta-analysis research that the benefits of plyometric exercises on vertical jump ability might transfer positively to sport-specific performances, such as kicking. The gains obtained in the kicking ability assessment might be attributed to PT-related neuromuscular adaptations of lower limb strength and power increases [23, 78, 125]. However, Campo et al. [74] and Sedano et al. [75] reported that six weeks of PT cannot improve soccer players’ kicking speed. The PT intervention program likely resulted in a higher ball speed due to enhanced energy transfer from the closer to the farther segments. Consequently, athletes might need to allow sufficient time for their explosive strength gains to translate into kinematic factors, ultimately leading to a remarkable increase in kicking speed [131, 132]. This result might explain why no substantial gains in kicking speed occurred following six weeks of PT [74]. The results of these studies suggest that an effective PT program lasting over six weeks could potentially enhance the explosive strength of soccer players. More importantly, these enhancements can be transferred to soccer kicks in terms of ball velocity. Furthermore, these neuromuscular adaptations likely affected the kicking performance’s biomechanical elements, such as the toe, ankle, knee, and hip’s maximum linear velocities upon ball contact, leading to superior ball kicking velocities and even maximal kicking distances [125]. In addition, multiple studies have highlighted the importance of balance for kicking performance in soccer [133–135]. For instance, Cerrah et al. [136] found a correlation between the kicking velocity of the dominant leg and the dynamic balance ability of both legs. Moreover, a growing body of research has demonstrated that PT programs can enhance the balance ability of players [30, 39, 137].
The effect of PT on speed dribbling
All players need to possess dribbling skills, but these abilities are particularly advantageous for attacking players who intend to penetrate a tight defense by running through congested areas [138]. We observed a moderate enhancement in the speed of dribbling (ES = 0.85) following PT among skilled players of basketball [77], handball [46], and soccer [99]. This improvement could be attributed to enhanced intermuscular coordination, speed, and precision of movement after plyometric exercises [139]. Specifically, speed dribbling is a technique used in handball where the player runs as fast as possible while keeping the ball out in front for close control [140]. It requires a combination of speed, agility, coordination, and ball control [140]. On the other hand, speed dribbling in soccer primarily relies on agility, which is defined as the ability to change direction quickly. There appears to be a positive correlation between agility and dribbling performance [141]. Similarly, it appears that PT had a more specific impact on basketball compared to other sports. The nature of basketball, which involves horizontal and lateral running and fast and quick movements between opposing players for ball crossing, may have led to greater responses to PT and subsequent enhancements in the change of direction [29], which could potentially benefit speed dribbling [141]. Furthermore, Apostolidis and Emmanouil [142] found that handgrip strength was a predictor of speed dribbling in basketball players. Based on the information mentioned above, it is crucial to implement effective training programs to enhance players’ physical fitness and optimize their game performance, specifically in skills such as speed dribbling [143]. PT has been widely studied by researchers as a means to improve athletes’ physical fitness [15, 45, 51]. Nonetheless, the ideal training volume for enhancing speed dribbling performance remains undetermined and requires further investigation. Consequently, it can be concluded that an effective dribbling technique plays a crucial role in determining the outcome of a match [144]. However, it is surprising that there are very few studies examining the impact of PT on ball players’ dribbling performance. Therefore, more research is needed to draw more reliable conclusions in this area.
The effect of PT on stride rate
The product of stride length and stride frequency is commonly used to define running speed [145]. Schubert et al. [146] suggested that changes in stride rate (i.e., shorter strides) could affect impact peak, kinetics, and kinematics, and therefore, might be considered a mechanism for modifying injury risk and facilitating recovery in runners. However, our meta-analysis found no significant effect of PT on runners’ stride rate performance [71, 89, 90, 93]. Similarly, a recent meta-analysis reported a non-significant impact (ES = 0.37) of jump training on stride rate in endurance runners [52]. The literature states that running speed improvement is usually accomplished by increasing stride length rather than stride frequency [147, 148]. Therefore, it is not unexpected that PT can enhance time trial performance without a significant improvement in stride rate performance. Furthermore, there is currently no evidence in the literature to suggest that neuromuscular adaptations resulting from plyometric exercises lead to changes in running biomechanics, such as stride rate [149]. In this sense, the lack of specificity in the PT program may have contributed to the non-significant effect on stride rate performance. Future studies should aim to investigate which types of plyometric jump drills (e.g., horizontal, vertical) or their combination with other training methods can effectively improve stride rate measures.
Additional analysis
Our study conducted subgroup analyses to investigate whether factors such as the athlete’s sex, age, and training variables had any impact on the effect of PT on their technical skill performance. However, our findings suggested that these factors did not have any significant effect on the enhancement of kicking velocity and distance, throwing velocity, speed dribbling, and stride rate performance after PT intervention, except for the subgroup analysis based on the length of the PT program. We found that longer PT interventions (over 7 weeks) resulted in greater improvements in throwing velocity. The results of our study align with previous meta-analyses that reported no significant impact of sex, age, and training variables on the effectiveness of PT in enhancing physical fitness in athletes [16, 44]. Moreover, our findings support the notion that longer PT interventions may lead to greater improvements in throwing velocity among athletes, which is consistent with previous research showing that longer training interventions result in more significant physical fitness gains [20, 150]. Longer PT interventions may enable athletes to perform more volume of exercise drills, resulting in greater improvements in throwing speed. Indeed, previous literature has demonstrated a direct correlation between physical fitness and technical skill [42, 151]. In addition, our investigation into moderating factors on technical skill performance after PT may have been restricted by the preliminary nature of some of the studies. Hence, we cannot currently provide conclusive recommendations to athletes regarding the optimal training variables for PT to enhance their technical skills. Future research is necessary to determine the most effective PT strategies based on both athlete-specific and training-specific factors.
Limitations
There are several notable limitations of this systematic review that should be taken into consideration. Firstly, although including a significant number of studies on a diverse range of sports, this review did not cover other power-strength related sports like badminton, ice hockey, and martial arts. Secondly, due to the limited number of studies, the meta-analysis of the effects of PT on outcomes such as handball passing accuracy [46], swimming block start [73], and gymnastics halt vault outcomes [88] was precluded. Moreover, this review only includes three studies that specifically focus on female players, which restricts our understanding of the general efficacy of PT in improving technical skill performance in athletes. Thirdly, we were unable to perform additional analyses on PT frequency, length, total sessions, and weekly session time in some cases due to the limited availability of at least one of the moderators (less than three papers). Therefore, we cannot provide definitive recommendations on the optimal training variables for improving athletes’ technical skills. Fourthly, the use of a median split strategy to dichotomize continuous data (e.g., > 7 weeks vs. ≤ 7 weeks) may result in residual confounding and reduced statistical power. Fifthly, the restriction of the publication search to studies written in English may have confined the findings’ representation. Finally, according to the GRADE assessment, the level of certainty of the evidence for most of the study outcomes ranged from low to moderate, lowering confidence in the reported estimates.
Conclusions
Our findings have shown that PT can be effective in enhancing technical skills measures in youth or adult athletes. Notably, PT has demonstrated significant improvements in kicking velocity and distance (i.e., soccer), throwing velocity (i.e., handball, baseball, water polo, tennis), and speed dribbling performance (i.e., soccer, handball, basketball). However, no significant effects on runners’ stride rate performance were observed. Sub-group analyses suggest that longer PT (> 7 weeks) interventions appear to be more effective for improving throwing velocity. However, to fully determine the effectiveness of PT in improving sport-specific technical skill outcomes and ultimately enhancing competition performance, further high-quality research covering a wider range of sports is required.
Practical application
This review’s conclusions offer practical consequences for sports coaches, trainers, and players. PT may be recommended as a training strategy to improve technical skill performance, especially for team sports athletes. Moreover, one significant advantage of this training is that it can be performed using inexpensive equipment such as medicine balls and jump boxes/hurdles. This feature makes it simple to incorporate into regular training regimens [10]. According to the results of the current review, there are no clear dose relationships evidence to recommend the optimal training variables to improve technical skill performance among athletes. As a general recommendation, trainers could consider exposing trainees to 1–3 sessions of 6–60 minutes each for a period of 4–16 weeks, as this time frame provides a suitable stimulus. Nevertheless, additional well-designed studies are necessary to identify the optimal dosages and analyze the interactions among training variables, with the goal of further enhancing the technical skills of the athletic population.
References
- 1. Smith DJ. A framework for understanding the training process leading to elite performance. Sports Medicine. 2003;33:1103–1126. pmid:14719980
- 2. Farley JB, Stein J, Keogh JWL, Woods CT, Milne N. The relationship between physical fitness qualities and sport-specific technical skills in female, team-based ball players: a systematic review. Sports Medicine.—Open. 2020; 6:18. pmid:32297147
- 3. Robertson SJ, Burnett AF, Cochrane J. Tests examining skill outcomes in sport: a systematic review of measurement properties and feasibility. Sports Medicine. 2014; 44: 501–518. pmid:24293244
- 4. Breivik G. The role of skill in sport. Sport, Ethics and Philosophy. 2016;10: 222–236. https://doi.org/10.1080/17511321.2016.1217917.
- 5. Whiteside D, Elliott B, Lay B, Reid M. The effect of age on discrete kinematics of the elite female tennis serve. Journal of Applied Biomechanics. 2013; 29: 573–582. pmid:23270869
- 6. Vetter S, Schleichardt A, Köhler HP, Witt M. The Effects of eccentric strength training on flexibility and strength in healthy samples and laboratory settings: a systematic review. Frontiers in Physiology. 2022; 13: 1–13. pmid:35574461
- 7. Hanin Y, Hanina M. Optimization of performance in top-level athletes: an action-focused coping approach. International Journal of Sports Science & Coaching. 2009; 4:47–91. https://doi.org/10.1260/1747-9541.4.1.47
- 8. Feros SA, Young WB, O’Brien BJ. Efficacy of combined general, special, and specific resistance training on pace bowling skill in club-standard cricketers. The Journal of Strength & Conditioning Research. 2020;34:2596–2607. pmid:30741863
- 9. Luo S, Soh KG, Nasiruddin NJ, Sun H, Du C, Soh KL. Effect of core training on skill performance among athletes: A systematic review. Frontiers in Physiology. 2022; 13:915259. pmid:35755428
- 10. Fernandez-Fernandez J, Ellenbecker T, Sanz-Rivas D, Ulbricht A, Ferrauti A. Effects of a 6-week junior tennis conditioning program on service velocity. Journal of Sports Science & Medicine. 2013; 12:232–239. pmid:24149801
- 11. Deng N, Soh KG, Huang D, Abdullah B, Luo S, Rattanakoses W. Effects of plyometric training on skill and physical performance in healthy tennis players: a systematic review and meta-analysis. Frontiers in Physiology. 2022;13:1024418. pmid:36505069
- 12. Davies G, Riemann BL, Manske R. Current concepts of plyometric exercise. International Journal of Sports Physical Therapy. 2015; 10:760–786. pmid:26618058
- 13. De Villarreal ES, Kellis E, Kraemer WJ, Izquierdo M. Determining variables of plyometric training for improving vertical jump height performance: a meta-analysis. The Journal of Strength & Conditioning Research. 2009; 23: 495–506. pmid:19197203
- 14. De Villarreal ES, Requena B, Newton RU. Does plyometric training improve strength performance? A meta-analysis. Journal of Science and Medicine in Sport. 2010; 13: 513–522. pmid:19897415
- 15. Slimani M, Chamari K, Miarka B, Del Vecchio FB, Chéour F. Effects of plyometric training on physical fitness in team sport athletes: a systematic review. Journal of Human Kinetics. 2016; 53:231–247. pmid:28149427
- 16. Sole S, Ramírez-Campillo R, Andrade DC, Sanchez-Sanchez J. Plyometric jump training effects on the physical fitness of individual-sport athletes: a systematic review with meta-analysis. PeerJ. 2021; 9:1–25. pmid:33717707
- 17. Nygaard Falch H, Guldteig Rædergård H, van den Tillaar R. Effect of different physical training forms on change of direction ability: a systematic review and meta-analysis. Sports Medicine-Open. 2019; 5:1–37. https://doi.org/10.1186/s40798-019-0223-y
- 18. Sammoud S, Bouguezzi R, Ramirez-Campillo R, Negra Y, Prieske O, Moran J, Chaabene H. Effects of plyometric jump training versus power training using free weights on measures of physical fitness in youth male soccer players. Journal of Sports Sciences. 2022; 40:130–137. pmid:34749577
- 19. Behringer M, Neuerburg S, Matthews M, Mester J. Effects of two different resistance-training programs on mean tennis-serve velocity in adolescents. Pediatric Exercise Science. 2013; 25:370–384. pmid:23986524
- 20. Pardos-Mainer E, Lozano D, Torrontegui-Duarte M, Cartón-Llorente A, Roso-Moliner A. Effects of strength vs. plyometric training programs on vertical jumping, linear sprint and change of direction speed performance in female soccer players: a systematic review and meta-Analysis. International Journal of Environmental Research and Public Health. 2021; 18:401. pmid:33419178
- 21. Clark M, Lucett S, Kirkendal DT. Plyometric training concepts for performance enhancement. National Academy of Sports Medicine. 2016; 24:207–226. Available from: https://downloads.lww.com/wolterskluwer_vitalstream_com/sample-content/9780781768030_NASM/samples/Chapter08.pdf
- 22. Heinecke M. Review of Literature: Neuromuscular adaptations to plyometrics. International Journal of Strength and Conditioning, 2021; 1:1. Available from: https://journal.iusca.org/index.php/Journal/article/view/53
- 23. Markovic G, Mikulic P. Neuro-musculoskeletal and performance adaptations to lower-extremity plyometric training. Sports Medicine. 2010; 40:859–895. pmid:20836583
- 24. De Villarreal SE, Requena B, Cronin JB. The Effects of plyometric training on sprint performance: a meta-analysis. The Journal of Strength & Conditioning Research. 2012; 26: 575–584. https://doi.org/10.1519/JSC.0b013e318220fd03
- 25. Ford HT, Puckett J, Drummond J, Sawyer K, Gantt K, Fussell C. Effects of three combinations of plyometric and weight training programs on selected physical fitness test items. Perceptual and Motor Skills. 1983; 56: 919–922. pmid:6877979
- 26. Willson GJ, Newton RV, Murphy AJ, Humphries BJ. The optimal training load for the development of dynamic athletic performance. Medicine and science in sports and exercise. 1993; 25: 1279–1286. pmid:8289617
- 27. Wild J, Bezodis NE, Blagrove RC, Bezodis IN. A biomechanical comparison of accelerative and maximum velocity sprinting: Specific strength training considerations. Professional Strength and Conditioning. 2011;21:23–37. Available from: https://research.stmarys.ac.uk/id/eprint/336/
- 28. Mackala K, Fostiak M. Acute effects of plyometric intervention—Performance improvement and related changes in sprinting gait variability. The Journal of Strength & Conditioning Research. 2015;29:1956–1965. https://doi.org/10.1519/JSC.0000000000000853
- 29. Asadi A, Arazi H, Young WB, de Villarreal, ES. The effects of plyometric training on change-of-direction ability: a meta-analysis. International Journal of Sports Physiology and Performance. 2016; 11: 563–573. https://doi.org/10.1123/ijspp.2015-0694
- 30. Ramirez-Campillo R, Garcia-Hermoso A, Moran J, Chaabene H, Negra Y, Scanlan AT. The effects of plyometric jump training on physical fitness attributes in basketball players: a meta-analysis. Journal of Sport and Health Science. 2021; 61:656–670. https://doi.org/10.1016/j.jshs.2020.12.005
- 31. Oxfeldt M, Overgaard K, Hvid LG, Dalgas U. Effects of plyometric training on jumping, sprint performance, and lower body muscle strength in healthy adults: a systematic review and meta‐analyses. Scandinavian journal of medicine & science in sports. 2019; 29:1453–1465. pmid:31136014
- 32. Bal BS, Singh S, Dhesi SS, Singh M. Effects of 6-week plyometric training on biochemical and physical fitness parameters of Indian jumpers. Journal of Physical Education and Sport Management. 2012; 3:35–40. https://doi.org/10.5897/JPESM11.072
- 33. Hammami M, Gaamouri N, Suzuki K, Shephard RJ, Chelly MS. Effects of upper and lower limb plyometric training program on components of physical performance in young female handball players. Frontiers in Physiology. 2020; 11:1028. pmid:33013446
- 34. Potach D. Plyometric and Speed Training. NSCA’s Essentials of Personal Training.2004. pp 411–459. Available from: https://www.researchgate.net/publication/322040348
- 35.
Turner A, Comfort P. Advanced strength and conditioning: an evidence-based approach. Routledge; 2022. Available from: https://scholar.google.com/scholar?hl=zh-CN&as_sdt=0%2C5&q=Advanced+strength+and+conditioning%3A+an+evidence-based+approach&btnG=
- 36. Ramírez-Campillo R, Andrade DC, Izquierdo M. Effects of plyometric training volume and training surface on explosive strength. The Journal of Strength & Conditioning Research. 2013;27:2714–22. pmid:23254550
- 37. Stojanovic E, McMaster VRDT, Milanovic Z. Effect of plyometric training on vertical jump performance in female athletes: a systematic review and meta-analysis. Sports Medicine. 2017; 47:975–986. pmid:27704484
- 38. Čaprić I, Stanković M, Manić M, Preljević A, Špirtović O, Dordević D, Spehnjak M, Damjan B, Sporiš G, Trajković N. Effects of plyometric training on agility in male soccer players-a systematic review. Journal of Men’s Health. 2022; 18:147. https://doi.org/10.31083/j.jomh1807147
- 39. Ramachandran AK, Singh U, Ramirez-Campillo R, Clemente FM, Afonso J, Granacher U. Effects of plyometric jump training on balance performance in healthy participants: a systematic review with meta-analysis. Frontiers in Physiology. 2021; 12:1760. pmid:34744772
- 40. Farley JB, Barrett LM, Keogh JWL, Woods CT, Milne N. The relationship between physical fitness attributes and sports injury in female, team ball sport players: a systematic review. Sports Medicine-Open. 2020; 6: 1–24. https://doi.org/10.1186/s40798-020-00264-9
- 41. Bradshaw EJ, Thomas K, Moresi M, Greene D, Braybon W, McGillivray K, Andrew K. Biomechanical field test observations of gymnasts entering puberty. In ISBS-Conference Proceedings Archive. 2014. Available from: https://ojs.ub.uni-konstanz.de/cpa/article/view/6002
- 42. Lambrich J, Muehlbauer T. Physical fitness and stroke performance in healthy tennis players with different competition levels: a systematic review and meta-analysis. PLoS One. 2022; 17:e0269516. pmid:35657986
- 43. Ramirez-Campillo R, García-de-Alcaraz A, Chaabene H, Moran J, Negra Y, Granacher U. Effects of plyometric jump training on physical fitness in amateur and professional volleyball: a meta-Analysis. Frontiers in Physiology. 2021; 12:636140. pmid:33716784
- 44. Deng N, Soh KG, Zaremohzzabieh Z, Abdullah B, Salleh KM, Huang D. Effects of combined upper and lower limb plyometric training interventions on physical fitness in athletes: a systematic review with meta-analysis. International Journal of Environmental Research and Public Health. 2023; 20:482. https://doi.org/10.3390/ijerph20010482
- 45. Sánchez M, Sanchez-Sanchez J, Nakamura FY, Clemente FM, Romero-Moraleda B, Ramirez-Campillo R. Effects of plyometric jump training in female soccer player’s physical fitness: a systematic review with meta-analysis. International Journal of Environmental Research and Public Health. 2020; 17:8911. pmid:33266195
- 46. Guadie WT. Effects of plyometric training on technical skill performance of handball team players at Debre Markos Town. International Journal of Sports Science and Physical Education. 2021; 6:41–47. https://doi.org/10.11648/j.ijsspe.20210603.11
- 47. Ramirez-Campillo R, Perez-Castilla A, Thapa RK, Afonso J, Clemente FM, Colado JC, de Villarreal ES, Chaabene H. Effects of plyometric jump training on measures of physical fitness and sport-specific performance of water sports athletes: a systematic review with meta-analysis. Sports Medicine-Open. 2022; 8:108. pmid:36036301
- 48. Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, Shamseer L, Tetzlaff JM, Moher D. Updating guidance for reporting systematic reviews: development of the PRISMA 2020 statement. Journal of Clinical Epidemiology. 2021; 134:103–112. pmid:33577987
- 49. McKenzie JE, Brennan SE, Ryan RE, Thomson HJ, Johnston RV, Thomas J. Defining the criteria for including studies and how they will be grouped for the synthesis”, Cochrane Handbook for Systematic Reviews of Interventions. 2019; 23:33–65. https://doi.org/10.1002/9781119536604.ch3
- 50. Sun H, Soh KG, Mohammadi A, Wang X, Bin Z, Zhao Z. (2022). Effects of mental fatigue on technical performance in soccer players: a systematic review with a meta-analysis. Frontiers in Public Health. 10. pmid:35937235
- 51. Ramírez-delaCruz M, Bravo-Sánchez A, Esteban-García P, Jiménez F, Abián-Vicén J. Effects of plyometric training on lower body muscle architecture, tendon structure, stiffness and physical performance: a systematic review and meta-analysis. Sports Medicine-Open. 2022; 8: 40. pmid:35312884
- 52. Ramirez-Campillo R, Andrade DC, García-Pinillos F, Negra Y, Boullosa D, Moran J. Effects of jump training on physical fitness and athletic performance in endurance runners: a meta-analysis: Jump training in endurance runners. Journal of Sports Sciences. 2021; 39: 2030–2050. https://doi.org/10.1080/02640414.2021.1916261
- 53. Ramirez-Campillo R, Sortwell A, Moran J, Afonso J, Clemente FM, Lloyd RS, Oliver JL, Pedley J, Granacher U. Plyometric-jump training effects on physical fitness and sport-specific performance according to maturity: a Systematic Review with Meta-analysis. Sports Medicine-Open. 2023;9:1–23. https://doi.org/10.1186/s40798-023-00568-6
- 54. Ramirez-Campillo R, Álvarez C, García-Hermoso A, Ramírez-Vélez R, Gentil P, Asadi A, Chaabene H, Moran J, Meylan C, García-de-Alcaraz A, Sanchez-Sanchez J. Methodological characteristics and future directions for plyometric jump training research: a scoping review. Sports Medicine. 2018; 48:1059–1081. pmid:29470823
- 55. De Morton NA. The PEDro scale is a valid measure of the methodological quality of clinical trials: a demographic study. Australian Journal of Physiotherapy. 2009; 55:129–133. pmid:19463084
- 56. Maher CG, Sherrington C, Herbert RD, Moseley AM, Elkins M. Reliability of the PEDro scale for rating quality of randomized controlled trials. Physical Therapy. 2003; 83:713–721. https://doi.org/10.1093/ptj/83.8.713 pmid:12882612
- 57. Guyatt GH, Oxman AD, Akl EA, Kunz R, Vist G, Brozek J, et al. GRADE guidelines: 1. Introduction-GRADE evidence profiles and summary of findings tables. Journal of Clinical Epidemiology. 2011;64(4):383–394. pmid:21195583
- 58. Zhang Y, Alonso-Coello P, Guyatt GH, Yepes-Nuñez JJ, Akl EA, Hazlewood G, et al. GRADE Guidelines: 19. Assessing the certainty of evidence in the importance of outcomes or values and preferences—risk of bias and indirectness. Journal of Clinical Epidemiology. 2019;111:94–104. pmid:29452223
- 59. Zhang Y, Coello PA, Guyatt GH, Yepes-Nuñez JJ, Akl EA, Hazlewood G, et al. GRADE guidelines: 20. Assessing the cer- tainty of evidence in the importance of outcomes or values and preferences—inconsistency, imprecision, and other domains. Journal of clinical epidemiology. 2019;111:83–93. pmid:29800687
- 60. Guyatt G, Oxman AD, Kunz R, Brozek J, Alonso-Coello P, Rind D, et al. Corrigendum to GRADE guidelines 6. Rating the quality of evidence-imprecision (J Clin Epidemiol 2011;64:1283–1293). Journal of Clinical Epidemiology. 2021;137:265. https://doi.org/10.1016/j.jclinepi.2021.04.014
- 61. Valentine JC, Pigott TD, Rothstein HR. How many studies do you need?: a primer on statistical power for meta-analysis. Journal of Educational and Behavioral Statistics. 2010; 35:215–247. https://doi.org/10.3102/1076998609346961.
- 62. Drevon D, Fursa SR, Malcolm AL. Intercoder reliability and validity of WebPlotDigitizer in extracting graphed data. Behavior Modification. 2016;41:323–339. pmid:27760807
- 63. Deeks JJ, Higgins JP, Altman DG et al. Analysing data and undertaking meta-analyses. Cochrane handbook for systematic reviews of interventions, 2019; 241–284. https://doi.org/10.1002/9781119536604.ch10
- 64. Kontopantelis E, Springate DA, Reeves D. A re-analysis of the Cochrane Library data: the dangers of unobserved heterogeneity in meta-analyses. PLoS One. 2013;8: e69930. pmid:23922860
- 65. Hopkins WG, Marshall SW, Batterham AM, Hanin J. Progressive statistics for studies in sports medicine and exercise science. Medicine & Science in Sports & Exercise. 2009;41:3–13. pmid:19092709
- 66.
Higgins JP, Deeks JJ, Altman DG. Special topics in statistics. In: Higgins JP, Green S, editors. Cochrane handbook for systematic reviews of interventions: the Cochrane Collaboration; 2008. pp. 481–529. Available from: http://www.cochrane-handbook.org
- 67. Higgins JP, Thompson SG. Quantifying heterogeneity in a meta-analysis. Statistics in Medicine. 2002;21:1539–1558. pmid:12111919
- 68. Egger M, Davey Smith G, Schneider M, Minder C. Bias in meta-analysis detected by a simple, graphical test. BMJ. 1997;315:629–634. pmid:9310563
- 69. Moran JJ, Sandercock GR, Ramírez-Campillo R, Meylan CM, Collison JA, Parry DA. Age-related variation in male youth athletes’ countermovement jump after plyometric training: a meta-analysis of controlled trials. The Journal of Strength & Conditioning Research. 2017; 31: 552–565. pmid:28129282
- 70. Lee MY, Ha SI, Ju JS, Lee HY. The Effects of 8-week plyometrics training on fitness and soccer-specific performance in female middle school soccer players. Journal of International Education. 2019; 1:32–48. Available from: https://ic.suwon.ac.kr/usr/file/ic/%ED%86%B5%ED%95%A9%EB%B3%B8.pdf#page=37
- 71. Saunders PU, Telford RD, Pyne DB, Peltola EM, Cunningham RB, Gore CJ, Hawley JA. Short-term plyometric training improves running economy in highly trained middle and long distance runners. The Journal of Strength & Conditioning Research. 2006; 20:947–954. pmid:17149987
- 72. Carter AB, Kaminski TW, Douex AT Jr, Knight CA, Richards JG. Effects of high volume upper extremity plyometric training on throwing velocity and functional strength ratios of the shoulder rotators in collegiate baseball players. The Journal of Strength & Conditioning Research. 2007; 21:208–215. pmid:17313281
- 73. Bishop DC, Smith RJ, Smith MF, Rigby HE. Effect of Plyometric Training on Swimming Block Start Performance in Adolescents. The Journal of Strength & Conditioning Research. 2009; 23:2137–2143. pmid:19855343
- 74. Campo SS, Vaeyens R, Philippaerts RM, Redondo JC, De Benito AM, Cuadrado G. Effects of lower-Limb plyometric training on body composition, explosive strength, and kicking speed in female soccer players. The Journal of Strength & Conditioning Research. 2009; 23:1714–1722. https://doi.org/10.1519/JSC.0b013e3181b3f537
- 75. Sedano S, Matheu A, Redondo JC, Cuadrado G. Effects of plyometric training on explosive strength, acceleration capacity and kicking speed in young elite soccer players. Journal of Sports Medicine and Physical Fitness. 2011; 51:50–58. pmid:21297563
- 76. Escamilla RF, Ionno M, deMahy MS, Fleisig GS, Wilk KE, Yamashiro K, Mikla T, Paulos L, Andrews J. Comparison of three baseball-specific 6-week training programs on throwing velocity in high school baseball players. The Journal of Strength & Conditioning Research. 2012; 26:1767–1781. pmid:22549085
- 77. Sharma D, Multani NK. Effectiveness of Plyometric Training in the Improvement of Sports Specific Skills of Basketball Players. Indian Journal of Physiotherapy & Occupational Therapy. 2012; 6:77–82. Available from: https://www.i-scholar.in/index.php/ijpot/article/view/47915
- 78. Michailidis Y, Fatouros IG, Primpa E, Michailidis C, Avloniti A, Chatzinikolaou A, Barbero-Álvarez JC, Tsoukas D, Douroudos II, Draganidis D, Leontsini D. Plyometrics’ trainability in preadolescent soccer athletes. The Journal of Strength & Conditioning Research. 2013; 27: 38–49. pmid:22450257
- 79. Ramírez-Campillo R, Meylan C, Álvarez C, Henríquez-Olguín C, Martínez C, Cañas-Jamett R, Andrade DC, Izquierdo M. Effects of In-Season low-volume high-intensity plyometric training on explosive actions and endurance of young soccer players. The Journal of Strength & Conditioning Research. 2014; 28:1335–1342. pmid:24751658
- 80. Ramírez-Campillo R, Andrade DC, Álvarez C, Henríquez-Olguín C, Martínez Salazar C, Martín BS, Silva-Urra J, Burgos C, Izquierdo Redín M. The effects of interset rest on adaptation to 7 weeks of explosive training in young soccer players. Journal of Sports Science and Medicine. 2014; 13: 287–296. https://doi.org/10.1519/JSC.0000000000000283 pmid:24790481
- 81. Chelly MS, Hermassi S, Aouadi R, Shephard R. Effects of 8-week in-season plyometric training on upper and lower limb performance of elite adolescent handball players. The Journal of Strength & Conditioning Research. 2014; 28:1401–1410. pmid:24149768
- 82. De Villarreal ES, Suarez-Arrones L, Requena B, Haff GG, Ramos-Veliz R. Effects of dry-land vs. In-water specific strength training on professional male water polo players’ performance. The Journal of Strength & Conditioning Research. 2014; 28: 3179–3187. pmid:24818541
- 83. Ramírez-Campillo R, Burgos CH, Henríquez-Olguín C, Andrade DC, Martínez C, Álvarez C, Castro-Sepúlveda M, Marques MC, Izquierdo M. Effect of unilateral, bilateral, and combined plyometric training on explosive and endurance performance of young soccer players. The Journal of Strength & Conditioning Research. 2015; 29: 1317–1328. pmid:25474338
- 84. Ramírez-Campillo R, Gallardo F, Henriquez-Olguín C, Meylan CM, Martínez C, Álvarez C, Caniuqueo A, Cadore EL, Izquierdo M. Effect of vertical, horizontal, and combined plyometric training on explosive, balance, and endurance performance of young soccer players. The Journal of Strength & Conditioning Research. 2015; 29: 1784–1795. pmid:25559903
- 85. Ramírez-Campillo R, Henríquez-Olguín C, Burgos C, Andrade DC, Zapata D, Martínez C, Álvarez C, Baez EI, Castro-Sepúlveda M, Peñailillo L, Izquierdo M. Effect of progressive volume-based overload during plyometric training on explosive and endurance performance in young soccer players. The Journal of Strength & Conditioning Research. 2015; 29:1884–1893. pmid:25559905
- 86. Ramos-Veliz R, Suarez-Arrones L, Requena B, Haff GG, Feito J, Sa´ ez de Villarreal, EE. Effects of in-competitive season power-oriented and heavy resistance lower-body training on performance of elite female water polo players. The Journal of Strength & Conditioning Research. 2015; 29: 458–465. https://doi.org/10.1519/JSC.0000000000000643
- 87. De Villarreal SE, Suarez-Arrones L, Requena B, Haff GG, Ramos-Veliz R. Enhancing performance in professional water polo players. The Journal of Strength & Conditioning Research. 2015: 29:1089–1097. https://doi.org/10.1519/JSC.0000000000000707
- 88. Hall E, Bishop DC, Gee TI. Effect of Plyometric training on handspring vault performance and functional power in youth female gymnasts. PLoS One. 2016; 11: e0148790. pmid:26859381
- 89. Giovanelli N, Taboga P, Rejc E, Lazzer S. Effects of strength, explosive and plyometric training on energy cost of running in ultra-endurance athletes. European Journal of Sport Science. 2017; 17: 805–813. pmid:28394719
- 90. Ache-Dias J, Pupo, JD, Dellagrana, RA, Teixeira, AS, Mochizuki L, Moro, ARP. Effect of jump interval training on kinematics of the lower limbs and running economy. The Journal of Strength & Conditioning Research. 2018; 32: 416–422. https://doi.org/10.1519/JSC.0000000000002332
- 91. Ramirez-Campillo R, García-Pinillos F, García-Ramos A, Yanci J, Gentil P, Chaabene H, Granacher U. Effects of different plyometric training frequencies on components of physical fitness in amateur female soccer players. Frontiers in Physiology. 2018; 9:934. pmid:30065665
- 92. Ramirez-Campillo R, Alvarez C, García-Pinillos F, Sanchez-Sanchez J, Yanci J, Castillo D, Loturco I, Chaabene H, Moran J, Izquierdo M. Optimal reactive strength index: is it an accurate variable to optimize plyometric training effects on measures of physical fitness in young soccer players? The Journal of Strength & Conditioning Research. 2018; 32: 885–893. https://doi.org/10.1519/JSC.0000000000002467
- 93. Gómez-Molina J, Ogueta-Alday A, Camara J, Stickley C, Garcia-Lopez J. Effect of 8 weeks of concurrent plyometric and running training on spatiotemporal and physiological variables of novice runners. European Journal of Sport Science. 2018; 18: 162–169. pmid:29227735
- 94. Ramirez-Campillo R, Alvarez C, García-Pinillos F, Gentil P, Moran J, Pereira A, Loturco I. Effects of plyometric training on physical performance of young Male soccer players: Potential effects of different drop jump heights. Pediatric Exercise Science. 2019; 31:306–313. pmid:30736711
- 95. Ramirez-Campillo R, Álvarez C, García-Pinillos F, García-Ramos A, Loturco I, Chaabene H, Granacher U. Effects of combined surfaces vs. single-surface plyometric training on soccer players’ physical fitness. The Journal of Strength & Conditioning Research. 2020; 34:2644–2653. pmid:30664111
- 96. Vera-Assaoka T, Ramirez-Campillo R, Alvarez C, Garcia-Pinillos F, Moran J, Gentil P, Behm D. Effects of maturation on physical fitness adaptations to plyometric drop jump training in male youth soccer players. The Journal of Strength & Conditioning Research. 2020; 34:2760–2768. pmid:32986391
- 97. Aloui G, Hermassi S, Hayes LD, Shephard RJ, Chelly MS, Schwesig R. Effects of elastic band plyometric training on physical performance of team handball players. Applied Sciences. 2021; 11: 1309. https://doi.org/10.3390/app11031309
- 98. Alp M, Ozdinc M. Effects of Plyometric trainings on upper extremity anaerobic power and shotspeed in male handball players. European Journal of Educational Sciences. 2021; 8:60–67. https://doi.org/10.19044/ejes.v8no2a60
- 99. Çalışkan Ö, Arikan Ş. The effect of plyometric training on some motoric and technical parameters in 13–15 age soccer players. Turkish Journal of Sport and Exercise. 2021; 23:287–96. Available from: https://dergipark.org.tr/en/pub/tsed/issue/68024/950138
- 100. Wee EH, Boon AH, Ler HY. Effects of short-term weight training on lower extremity power, strength, endurance, and kicking speed in male college soccer players. Malaysian Journal of Sport Science and Recreation. 2023;19:95–110. https://doi.org/10.24191/mjssr.v19i1.21760
- 101. Van de Hoef PA, Brauers JJ, van Smeden M, Backx FJG, Brink MS. The effects of lower-extremity plyometric training on soccer-specific outcomes in adult male soccer players: a systematic review and meta-analysis. International Journal of Sports Physiology and Performance. 2020; 15:3–17. https://doi.org/10.1123/ijspp.2019-0565
- 102. Eraslan L, Castelein B, Spanhove V, Orhan C, Duzgun I, Cools A. Effect of plyometric training on sport performance in adolescent overhead athletes: a systematic review. Sports Health. 2021;13:37–44. pmid:32903164
- 103. Bedoya AA, Miltenberger MR, Lopez RM. Plyometric training effects on athletic performance in youth soccer athletes: a systematic review. The Journal of Strength & Conditioning Research. 2015;29:2351–60. pmid:25756326
- 104. Koch J, Riemann BL, Davies GJ. Ground reaction force patterns in plyometric push-ups. The Journal of Strength & Conditioning Research. 2012; 26:2220–2227. pmid:21986698
- 105. Singla D, Hussain ME, Moiz JA. Effect of upper body plyometric training on physical performance in healthy individuals: a systematic review. Physical Therapy in Sport. 2018; 29:51–60. pmid:29174999
- 106. Singla D, Hussain ME. Adaptations of the upper body to plyometric training in cricket players of different age groups. Journal of Sport Rehabilitation. 2019; 29: 697–706. pmid:31141445
- 107. Elumalai S. Impact of upper body plyometric training with and without skill movement training on Cricket ball throwing abili Impact of upper body plyometric training with and without skill movement training on Cricket ball throwing ability of male Cricketers. Journal of Information and Computational Science. 2019; 9: 918–927. Available from: https://www.academia.edu/43086798/Impact_of_upper_body_plyometric_training_with_and_without_skill_movement_training_on_Cricket_ball_throwing_ability_of_male_Cricketers
- 108. Ignjatovic AM, Markovic ZM, Radovanovic DS. Effects of 12- week medicine ball training on muscle strength and power in young female handball players. The Journal of Strength & Conditioning Research. 2012; 26: 2166–2173. pmid:22027860
- 109. Szymanski DJ, MCyntire JS, Szymanski JM, Bradford TJ, Schade RL, Madsen NH, Pascoe, DD. Effect of torso rotational strength on angular hip, angular shoulder, and linear bat velocities of high school baseball players. The Journal of Strength & Conditioning Research. 2007; 21: 1117–1125. https://doi.org/10.1519/R-18255.1
- 110. Marques M, Saavedra F, Abrantes C, Aidar F. Associations between rate of force development metrics and throwing velocity in elite team handball players: a short research Report. Journal of Human Kinetics. 2011; 29A:53–57. pmid:23487363
- 111. Malisoux L, Francaux M, Nielens H, Theisen D. Stretch-shortening cycle exercises: An effective training paradigm to enhance power output of human single muscle fibers. Journal of Applied Physiology. 2006; 100:771–779. pmid:16322375
- 112. Filipa A, Byrnes R, Paterno MV, Myer GD, Hewett TE. Neuromuscular training improves performance on the star excursion balance test in young female athletes. Journal of Orthopaedic & Sports Physical Therapy. 2010; 40:551–558. pmid:20710094
- 113. Pretz R. “Ballistic Six” plyometric training for the overhead throwing athlete. Strength & Conditioning Journal. 2004; 26:62–66. https://doi.org/10.1519/00126548-200412000-00014
- 114. Turgut E, Cinar-Medeni O, Colakoglu FF, Baltaci G. “Ballistic Six” upper-extremity plyometric training for the pediatric volleyball players. The Journal of Strength & Conditioning Research. 2019; 33:1305–1310. pmid:28945640
- 115. Grezios AK, Gissis IT, Sotiropoulos AA, Nikolaidis DV, Souglis AG. Muscle-contraction properties in overarm throwing movements. The Journal of Strength & Conditioning Research. 2006; 20: 117–123. pmid:16503670
- 116. McCluskey L, Lynskey S, Kei Leung C, Woodhouse D, Briffa K, Hopper D. Throwing velocity and jump height in female water polo players: Performance predictors. Journal of Science and Medicine in Sport. 2010; 13: 236–240. pmid:19442582
- 117. Ferragut C, Abraldes JA, Vila H, Rodriguez N, Argudo FM, Fernandes J. Anthropometry and throwing velocity in professional water polo by specific playing positions. Journal of Human Kinetics. 2011; 27: 31–44. https://doi.org/10.2478/v10078-011-0003-3
- 118. Stevens HB, Brown LE, Coburn JW, Spiering BA. Effect of swim sprints on throwing accuracy and velocity in female collegiate water polo players. The Journal of Strength & Conditioning Research. 2010; 24: 1195–1198. pmid:20386121
- 119. Ramos-Veliz R, Requena B, Suarez-Arrones L, Newton RU, Saez de Villarreal E. Effects of 18-week in-season heavy-resistance and power training on WP throwing speed, strength, jumping, and maximal sprint swim performance of elite male water polo players. The Journal of Strength & Conditioning Research. 2013; 25: 3399–3403. https://doi.org/10.1519/JSC.0000000000000240
- 120. Reid M, Giblin G, Whiteside D. A kinematic comparison of the overhand throw and tennis serve in tennis players: How similar are they really?. Journal of Sports Sciences, 2015; 33, 713–723. pmid:25517627
- 121. Hayes MJ, Spits DR, Watts DG, Kelly VG. The relationship between tennis serve velocity and select performance measures. The Journal of Strength & Conditioning Research. 2021; 35: 190–197.
- 122. Colomar J, Corbi F, Baiget E. Improving tennis serve velocity: review of training methods and recommendations. Strength & Conditioning Journal. 2022;10:1519. https://doi.org/10.1519/ssc.0000000000000733
- 123. Baiget E, Colomar J, Corbi F. Upper-limb force–time characteristics determine serve velocity in competition tennis players. International Journal of Sports Physiology and Performance. 2022; 17: 358–366. pmid:34794120
- 124. Masuda K, Kikuhara N, Demura S, Katsuta S, Yamanaka K. Relationship between muscle strength in various isokinetic movements and kick performance among soccer players. Journal of Sports Medicine and Physical Fitness. 2005; 45:44–52. pmid:16208290
- 125. Lees A, Asai T, Andersen TB, Nunome H, Sterzing T. The biomechanics of kicking in soccer: A review. Journal of Sports Sciences. 2010; 28:805–817. pmid:20509089
- 126. Maly T, Sugimoto D, Izovska J, Zahalka F, Mala L. Effect of muscular strength, asymmetries and fatigue on kicking performance in soccer players. International Journal of Sports Medicine. 2018; 39:297–303. pmid:29506307
- 127. Rodríguez-Lorenzo L, Fernandez-del-Olmo M, Sanchez-Molina JA, Martín-Acero R. Role of vertical jumps and anthropometric variables in maximal kicking ball velocities in elite soccer players. Journal of Human Kinetics. 2016; 53:143–154. pmid:28149419
- 128. Tessitore A, Perroni F, Cortis C, Meeusen R, Lupo C, Capranica L. Coordination of soccer players during preseason training. The Journal of Strength & Conditioning Research. 2011; 25:3059–3069. pmid:21993023
- 129. Nunome H, Ikegami Y, Kozakai R, Apriantono T, Sano S. Segmental dynamics of soccer instep kicking with the preferred and non-preferred leg. Journal of Sports Sciences. 2006; 24:529–541. pmid:16608767
- 130. Markovic G. Does plyometric training improve vertical jump height? a meta-analytical review. British Journal of Sports Medicine. 2007; 41:349–355. pmid:17347316
- 131. Dörge HC, Andersen TB, SØrensen H, Simonsen EB. Biomechanical differences in soccer kicking with the preferred and the non-preferred leg. Journal of Sports Sciences. 2002; 20:293–299. pmid:12003274
- 132. Haines TL, Erickson TM, McBride JM. Kicking power. Strength & Conditioning Journal. 2012; 34:52–56. https://doi.org/10.1519/SSC.0b013e318274ca58
- 133. Bigoni M, Turati M, Gandolla M, Augusti CA, Pedrocchi A, La Torre A,.Piatti M, Gaddi DBalance in young male soccer players: Dominant versus non-dominant leg. Sport Sciences for Health, 2017; 13, 253–258. https://doi.org/10.1007/s11332-016-0319-4
- 134. Tracey SY, Anderson DI, Hamel KA, Gorelick ML, Wallace SA, Sidaway B. Kicking performance in relation to balance ability over the support leg. Human Movement Science. 2012; 31: 1615–1623. pmid:22939850
- 135. Cè E, Longo S, Paleari E, Riboli A, Limonta E, Rampichini S, Coratella G, Esposito F. Evidence of balance training‐induced improvement in soccer‐specific skills in U11 soccer players. Scandinavian Journal of Medicine & Science in Sports, 2018; 28, 2443–2456. pmid:29885054
- 136. Cerrah AO, Bayram İ, Yildizer G, Uğurlu O, Şimşek D, Ertan H. Effects of functional balance training on static and dynamic balance performance of adolescent soccer players. International Journal of Sport Exercise and Training Sciences. 2016; 2: 73–81. https://doi.org/10.18826/ijsets.38897
- 137. Alikhani R, Shahrjerdi S, Golpaigany M, Kazemi M. The effect of a six-week plyometric training on dynamic balance and knee proprioception in female badminton players. The Journal of the Canadian Chiropractic Association, 2019; 63:144. pmid:31988535
- 138. Branquinho L, Ferraz R, Mendes PD, Petricia J, Serrano J, Marques MC. The effect of an in-season 8-week plyometric training programme followed by a detraining period on explosive skills in competitive junior soccer players. Montenegrin Journal of Sports Science and Medicine. 2020; 9: 33–40. https://doi.org/10.26773/mjssm.200305
- 139.
Houglum PA. Therapeutic exercise for musculoskeletal injuries 4th edition. Champaign, IL: Human Kinetics; 2016.
- 140. Suresh K, Mohan K, Rajeswaran. Effect of handball specific skill training on selected skills and over all playing ability of inter-collegiate men handball players. Journal of Academic Sports Scholar, 2014; 3: 2277–3665. Available from: http://oldpesrj.lbp.world/UploadedArticles/234.pdf
- 141. Daulay B, Azmi F. Coordination and agility: How is the correlation in improving soccer dribbling skills? Journal Sport Area. 2021; 6: 147–161. https://doi.org/10.25299/sportarea.2021.vol6(2).6355
- 142. Apostolidis N, Emmanouil Z. The influence of the anthropometric characteristics and handgrip strength on the technical skills of young basketball players. Journal of Physical Education and Sport. 2015; 15: 330. https://doi.org/10.7752/jpes.2015.02050
- 143. Hoffman JR, Tenenbaum G, Maresh CM, Kraemer WJ. Relationship between athletic performance tests and playing time in elite college basketball players. The Journal of Strength & Conditioning Research. 1996; 10:67–71. https://doi.org/10.1519/1533-4287(1996)010<0067:RBAPTA>2.3.CO;2
- 144. Li F, Rupčić T, Knjaz D. The effect of fatigue on kinematics and kinetics of basketball dribbling with changes of direction. Kinesiology. 2021; 53: 296–308. Available from: https://hrcak.srce.hr/ojs/index.php/kinesiology/article/view/17087
- 145. Bernans E, Abolins V, Lanka J. Does step frequency as a single factor affect running economy? A systematic review. Journal of Human Sport and Exercise. 2023; 18: 743–754. https://doi.org/10.14198/jhse.2023.183.20
- 146. Schubert AG, Kempf J, Heiderscheit BC. Influence of stride frequency and length on running mechanics: a systematic review. Sports Health. 2014;6:210–217. pmid:24790690
- 147. García-Pinillos F, García-Ramos A, Ramírez-Campillo R, Latorre-Román P, Roche-Seruendo LE. How do spatiotemporal parameters and lower-body stiffness change with increased running velocity? a comparison between novice and elite level runners. Journal of Human Kinetics. 2019; 70: 25–38. pmid:31915473
- 148. García-Pinillos F, Lago-Fuentes C, Latorre-Román P, Pantoja-Vallejo A, Ramirez-Campillo R. Jump-rope training: Improved 3-km time-trial performance in endurance runners via enhanced lower-limb reactivity and foot-arch stiffness. International Journal of Sports Physiology and Performance, 2020; 15: 927–933. pmid:32163923
- 149. Trowell D, Vicenzino B, Saunders N, Fox A, Bonacci J. Effect of strength training on biomechanical and neuromuscular variables in distance runners: a systematic review and meta-Analysis. Sports Medicine. 2020; 50: 133–150. pmid:31541409
- 150. Ramirez-Campillo R, Castillo D, Raya-González J, Moran J, de Villarreal ES, Lloyd RS. Effects of plyometric jump training on jump and sprint performance in young male soccer players: a systematic review and meta-analysis. Sports Medicine. 2020; 50: 2125–2143. pmid:32915430
- 151. Duncan MJ, Eyre ELJ, Noon MR, Morris R, Thake CD, Clarke ND, Cunningham AJ. Actual and perceived motor competence mediate the relationship between physical fitness and technical skill performance in young soccer players. European Journal of Sport Science. 2022; 22: 1196–1203. pmid:34187318