Eligibility criteria

The systematic search comprised observational studies written in English, prospective or retrospective and cohort studies. Studies were eligible for inclusion according to the following criteria: (i) evaluation of wheelchair basketball athletes; (ii) using skill tests (defined as agility, speed, ball maneuverability, slalom, etc.) and (iii) papers needed to be published in peer-reviewed journals. Studies were excluded from the analysis based on the following criteria: (i) articles with poor description of the test methodology, (ii) participants not classified as wheelchair basketball athletes (less than one year of practice) and (iii) Participants were not people without disability.

Search strategy

Searches of the electronic databases PubMed/Medline, ScienceDirect, Scopus, Web of Science, and Google Scholar were performed from inception to January 2021 with up to date in January 2022. Articles were retrieved from electronic databases using the following search strategy: "wheelchair basketball" AND performance OR "Athletic Performances" OR "Sports Performance" OR "Functional Performance" OR "Physical Performance" AND "field tests" OR "skill tests". These words needed to occur in the title or in the abstract of the manuscript.

Selection process and data collection process

Identified articles in systematic search were initially checked for relevance by two independent researchers (CMAFS and KSGS). The articles were selected after a sequential reading of the title and abstract, always in this order. Subsequently, the researchers reviewed the full texts of potentially eligible articles. A third researcher (AACS) resolved any disagreement regarding the inclusion of the study among reviewers. Fig 1 shows the flow chart of the studies during the study selection process. The records retrieved from databases are available in S1 Table.

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Fig 1. PRISMA flow diagram of the studies’ selection.

Figure based on https://prisma-statement.org/prismastatement/flowdiagram.aspx [5].

https://doi.org/10.1371/journal.pone.0276946.g001

Data collection was performed by two independent researchers (CMAFS and KSGS), supported by a third researcher (AACS) when necessary. Data extracted from studies included objectives, sample (number, sport class, and training level), skill tests used, main outcomes, and results of the skill tests.

Study risk of bias assessment

The quality of the study was evaluated by two researchers (CMAFS and KSGS) according to the Evaluation Tool for Cross Sectional Studies (AXIS tool) [7], which is considered an appropriate tool to assess the methodological quality of studies in systematic reviews. This tool consists of twenty questions divided in five groups (introduction, methods, results, discussion and other) that evaluate the quality and risk of bias of cross-sectional studies.

Study selection

Through searches, a total of 1279 articles were found (Fig 1 and Table 1). These studies were inserted into an excel sheet (© Microsoft Corporation) and duplicates were removed, leaving 648 studies. Titles and abstracts were read and 92 manuscripts were selected; after that, inclusion and exclusion criteria were applied, and for these review 23 articles were remaining.

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Table 1. Search strategy.

https://doi.org/10.1371/journal.pone.0276946.t001

Study participants

A total of 838 athletes competing at different playing standards. Of the 23 studies, 17 divided their athletes by sport class (class 1.0–1.5 = 182 athletes, class 2.0–2.5 = 196 athletes; class 3.0–3.5 = 164 athletes, and class 4.0–4.5 = 124 athletes). Three studies divided it into category A (Functional Classification Class 1.0–2.5) and B (Functional Classification Class 3.0–4.5) [8–10]. One study divided into an intervention group and a control group [11]. One study divided into elite wheelchair basketball players at different league levels [12]. A study divided according to medical classification [13].

Study description

In Table 2 are described the data extraction. Regarding applied skill tests, we find that pass tests (speed pass, pass accuracy, pass for distance, two-handed chest pass, medicine ball pass, maximal pass) were used in 11 articles [2,3,12,14–21]. Sprint tests (20 m sprint test without and with ball, 5 m sprint test without and with ball, 3 m sprint test, 10 m sprint test, 10x5 m sprint test, 30 seconds sprint test) were used in 13 articles [2,12,16–18,20,22–28].

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Table 2. Data extraction.

https://doi.org/10.1371/journal.pone.0276946.t002

The tests with the least number of applications were shooting test (free throw shooting, basket per minute, medicine ball throw, zone shot, spot shot, shot and lay-up) were presented in 14 studies [2,10,12–20,22,24,29]. Agility tests (slalom with and without ball, ball pick-up, 3-6-9 m drill test, agility drill test, agility T test, figure eight with ball test) were also used in 8 studies [2,9,10,12,16–18,22]. Drible and obstacle drible test presented in 5 studies [3,11,14,19,24]. Endurance test (6 min endurance race, suicide, yo yo 10 m recovery test, modified Cooper 12-minute test) were presented in 5 articles [2,12,17,18,22]. Lay-up tests in 2 articles [12,22]. Rebounding [14], bounce spot and bounce spin [19], catching [19], bilateral handgrip [16], envelope drill test [17], playing time [3] and wheelchair mobility performance WMP test [27] were presented by one article each. For more information about protocol tests, see Table 3.

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Table 3. Skill tests protocol.

https://doi.org/10.1371/journal.pone.0276946.t003

Results of the skill tests

Table 2 shows the difference in test results between the levels of the sport class, so that the highest classes showed better performance results [2,10,11,14,16–18,24]. Differences are also observed when considering the level of training, high-level athletes showed better results when compared to amateur athletes [12,19]. Bergamini et al (2015) [23] assessed strength and power between different injury levels and observed higher levels of strength and power as a result (Δt: push cycle duration; f: push cycle frequency; Fp: peak progression force; sym: bilateral symmetry index) better performance in propulsion tests on athletes who are introduced to the training group. One of the articles found no significant difference between the elite and sub-elite groups (classes IWBF and NWBA) in all subscores and scores [19]. In another study it was observed that there is a difference between the performance in different positions of the players in the passing and dribbling tests (p <0.05), in which central attackers showed better results compared to the other positions [3]. The study by Ribeiro Neto et al (2021) [9] found a difference in strength and power performance between the gender and a significant correlation of the medicine ball test with all other wheelchair basketball field tests evaluated (R2 ranging from 0.810 to 0.995; P ≤ 0.05).

Skills assessed

Table 4 shows the skills explored in each study in its battery of tests. Pass skill has the highest prevalence in studies [2,3,12,14–19,22,24] followed by speed, agility, dribbling, and shooting [2,10,12–14,16–18,23]. Force [2,9,16] is the least explored skill followed by Pick-up [2,21,22,28] in testing during studies.

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Table 4. Ability of wheelchair skills tests.

https://doi.org/10.1371/journal.pone.0276946.t004

Quality assessment

Through subjective evaluation of the methodological quality of studies using the AXIS tool, we identified that, in general, the articles included in this systematic review have a low risk of methodological bias. Assessing methodological quality of studies is important because results that come from studies with low risk of bias are more reliable, and for a systematic review, this point is important because it makes the scientific evidence stronger.

Skill tests: Main tests and skills assessed

Pass and sprint tests were the most frequently cited in the articles included here. The pass is a skill required throughout all wheelchair basketball games [31]. During the completion of the pass, different muscle groups are involved and trunk muscles are very important to stabilize the body; consequently, athletes of different classes will be presented with different ways of performing the pass and different performances [32]. Thereby, assessing the pass is important to improve the training of this skill and improve individual and collective performance. Pass tests assess the athlete’s ability to perform these activities and can also be used as a way of assessing upper limb function [18]. In a study, the maximal passes test of one hand (baseball and hook passes) was used and it was possible to identify differences between classification levels [18], which allows us to say that through this evaluation we can have an answer as to the degree of functionality of the upper limbs of wheelchair basketball athletes.

There are several passing techniques, which will be used according to the game situation [33], and in the case of wheelchair basketball, it will also vary according to the sport class. So, which test to use? The answer to this question can be found in the study by Izzo and Russo (2011) who evaluated passing techniques in 150 games in the high-level Italian league, NCAA and NBA. They found that the two-handed chest pass was the most common and easiest to perform during matches [34]. These results indicate that, taking into account that the two-handed chest pass is the most performed in matches, the two-handed chest pass test would be the most indicated to evaluate this skill. However, it is noteworthy that in wheelchair basketball this result may not be the same, since during the pass the athlete may be touching the chair, for example, and no study has observed which passing technique is the most used in games of Wheelchair basketball.

Sprint tests measure speed to cover a predetermined distance, cardiovascular capabilities, and performance. Yanci et al. (2015) [28], used T-test and Yo-Yo 10 m recovery test to evaluate agility and endurance performance of wheelchair basketball athletes and identified that the tests are reliable and therefore can be appropriate instruments for measuring physical fitness in wheelchair basketball [28]. The Yo-Yo test assesses an individual’s ability to perform intense exercise intermittently. Consequently, leading to the end of the test a predominance of the aerobic metabolic pathway [35]. In the version described by Yanci (2015) [28], due to the difference between running and wheel propulsion, the fixed distance to be covered during the test was reduced to 10 meters.

In wheelchair basketball there is an intermittent feature, where athletes alternate short and intense efforts, acceleration, deceleration, change of direction with active or passive recovery periods, with expressive participation of aerobic capacity during the match [28,36]. The training and play of wheelchair basketball are based on the aerobic pathway to provide athletes with energy [37]. Furthermore, the development of such a pathway can contribute to recovery between intermittent efforts and, consequently, to maintaining a higher intensity for a longer period of time, contributing to better endurance performance [38,39].

Evaluation of endurance performance becomes difficult in terms of the different methodologies applied, with different tests and variables analyzed (VO2, lactate, distance, heart rate) [28,36,37,40]. Hutzler (1993), comparing the aerobic and anaerobic performance of 11 elite Israeli wheelchair basketball players using an arm ergometer. Ergometric tests included a continuous aerobic maximum work capacity test and a 30 second all-out anaerobic test in the arm. The author concludes that the result of the arm ergometer may have a limited performance value for athletes.

To assess the aerobic capacity of the players, a suicide test was performed in two studies [20–22]. As well as, Yanci (2015) [28] and Tachibana (2019) [18] to analyze the physical characteristics measured by sprint, agility, strength and endurance with field tests on wheelchair basketball players demonstrated that the tests are reliable and can be appropriate instruments for coaches and athletes measuring endurance performance in WB. Yüksel and Sevindi. (2018) [12] used the 6-minute endurance running test to assess athletes’ endurance performance.

Sprinting is another important skill in wheelchair basketball, throughout the game athletes need to be at speed and perform other activities at the same time as they carry out wheelchair propulsion, and this skill is closely linked to performance [41]. Taking into account this characteristic, the interesting thing for this skill is to use tests that assess speed at the same time as other activities are performed, to simulate what could happen in a match. In this sense, the maximum speed test of 20 meters with the ball is interesting for this skill and also the WMP test because it is a battery of tests that simulate different game situations while the athletes perform sprints.

Both passing ability and speed are fundamental skills in wheelchair basketball and evaluating them provides an overview of an athlete’s performance on the court. The protocols for all tests are described in Table 3.

Sport class, training level, and skill tests

Based on the results presented in this review, low-sport-class athletes (less functionality) showed worse results compared to high-class athletes (more functionality). These results are particularly interesting when we talk about evidence-based classification, which seeks to classify athletes based on empirical evidence [42]. In this sense, further investigation is need about skill tests as tools during the classification process because most are not time-consuming and practical. In fact some studies have already suggested the potential of using skill tests in the classification of wheelchair basketball athletes and have shown positive results [27,43,44].

For this to be a reality, it is still necessary to delimit parameters that define each sport class, with well-defined values (minimum and maximum value). Thus, the ideal for the use of these tests of skill during the classification would be the creation of a battery of tests with specific and well-defined objectives and the creation of tables of values, delimiting and characterizing each class based on the parameters to be adopted.

A similar phenomenon occurs when observing the level of training of athletes, those who have a higher level of training showed better results in skills tests. This result was already expected as the skills can be improved through training. Still, this result is interesting for structuring the training. Based on the results of skill tests, coaches can meet the specific demands of athletes, the tests themselves can be used as training programs.

Limitations of the review

As it is a systematic review, our limitations are related to the studies that are inserted here. In addition, even though the sample is composed of a specific population (wheelchair basketball athletes) it is heterogeneous regarding training level, sport class, age, which may have affected the general interpretation.

Implications for research and practice

Our study describes and synthesizes the main skills tests found in the literature. The links between results of skill tests and sport classification / training level made in this work, provide theoretical reference for future research in this field of study (both in sports classification and training). Currently, studies have used skill tests and collected results beyond what is generally found in the general literature (results are often described through the time the test is performed and the distance covered). Through the aid of technology (such as the use of accelerometers), these studies have analyzed linear acceleration and angular velocity [27,43–46].

With the results found here, with further investigation the skills tests could be considered for use during the evidence-based classification process of wheelchair basketball. In addition, these tests can be used by trainers to assess the skills that need to be improved in training, thus developing specific training circuits for each demand.