The authors have declared that no competing interests exist.
Systematic reviews of balance control have tended to only focus on the effects of single lower-limb stimulation strategies, and a current limitation is the lack of comparison between different relevant stimulation strategies. The aim of this systematic review and meta-analysis was to examine evidence of effects of different lower-limb sensory stimulation strategies on postural regulation and stability. Moderate- to high- pooled effect sizes (Unbiased (Hedges’
During human postural control, individuals constantly regulate movements, subconsciously, based on perceived information to achieve postural stability. In the past two decades, many studies have been devoted to investigating effects of lower-limb sensory stimulation strategies (e.g. tapes/sleeves/ braces/compression; application of Stochastic Resonance; textured insoles and footwear) for postural regulation and balance performance in different populations. Common to intervention strategies is the assumption that lower-limb stimulation increases somatosensory feedback. Specifically, it has been proposed that increasing attunement to plantar cutaneous afferent information sent to the Central Nervous System (CNS) [
To the best of our knowledge, no published article has focused on the comparison of the effects of various lower-limb stimulation strategies such as tapes, braces, compression garments, textured insoles and footwear, and application of added random sub-threshold electrical or mechanical stimulation (noise) (exploiting a mechanism referred to as Stochastic Resonance [SR]). To date, systematic reviews have tended to only focus on a single stimulation strategy such as the role of textured materials [
The specific purposes of this review article are: i) to review systematically the effects of lower-limb stimulation strategies on sensory regulation of postural control and balance performance ii) to meta-analyze the effect of these lower-limb stimulation strategies on various populations (healthy young adults; older adults; individuals with lower-limb injuries) and under different task constraints (unipedal; bipedal; eyes open; eyes-closed).
The main focus of early research using wearable garments (e.g., tapes, braces and compression garments) was related to injury and re-injury prevention [
Furthermore, Kraemer et al. [
Michael [
Textured materials, especially textured insoles, have also emerged as an important research area in somatosensory intervention studies. Texture insoles are deemed to be beneficial because they increase the sensitivity of plantar cutaneous afferent information sent to the CNS [
In addition to wearable garments and textured insoles, the use of sub-threshold electrical or mechanical stimulation (white noise) for stimulating soles of the feet, known as application of SR, has also received substantial research attention. Various studies introducing sub-sensory electrical or mechanical noise to enhance postural regulation were conducted between 2002 to 2014 (e.g., Collins et al. [
From the motor system perspective, two studies highlighted the potential benefits of introducing SR in the motor systems of humans and cats [
The majority of the reviewed studies showed promising findings on effects of individual lower-limb stimulation strategy on postural regulation systems. This quantified review seeks to provide new insights on this area of work with specific focus on the heterogeneity, similarities and differences between intervention strategies in enhancing postural regulation systems.
The search and reporting format were conducted in accordance with the PRISMA statement (
Lower-limb stimulation strategies: “Textured/Textured insoles or footwear”, “Compression/Compression garments and stocking”, “Tapes and braces”, “Application of Stochastic Resonance/ added noise.”
Task- related: “Postural Control” and “Balance.”
The first reviewer (lead author) performed the search of the electronic databases and screened the potentially relevant articles based on abstracts and titles at the initial screening. Then, the retrieved articles were evaluated separately by the first and fourth authors using the following inclusion and exclusion criteria for full review, with any disagreement resolved by consensus.
Inclusion Criteria:
No restrictions on study design.
Studies published in English between 1995 and October 2016.
Studies investigating the effects of behavioural measures of textured materials (insoles; stocking), wearable garments (compression garments; braces; tapes), and application of Stochastic Resonance during tasks involving postural stability and balance (static; dynamic) in non-fatigue conditions.
The primary outcome measures consisted of the center of pressure (CoP) related measurements, the center of mass (CoM), distance reach, balance time, and gait variables.
The primary outcomes included in the meta-analysis were the center of pressure (CoP) related measurements such as CoP sway and standard deviations (SD) in medial-lateral (ML), and anterior-posterior (AP) directions; path length; recurrence quantification analysis (RQA) measurements.
In the meta-analysis, studies were required to report means and standard deviations of outcome measures interacting with lower-limb stimulation strategies.
Exclusion Criteria:
Studies that use cumbersome and expensive equipment in investigating vibration effects on postural ability, which is more complex and costly for end-users, compared to the simpler addition of electrical stimulation, textured, and wearable materials. Furthermore, vibration effects usually produce stimulation above the consciously perceived threshold level, which would negate the role of Stochastic Resonance in enhancing proprioception and haptic perception at a sub-threshold level.
Studies where outcome variables are not compatible for comparison, (means and standard deviations) in the meta-analysis.
Studies in stroke, diseases resulting in neuropathy (e.g. Multiple Sclerosis and Parkinson Disease) and cerebral palsy populations, with some damage to the brain, impairing physical mobility and postural control mechanisms.
In this context of study, three main groups of the lower-limb stimulation strategies were based on the characteristics—wearable garments, textured materials, and an application of stochastic resonance. Compression garments (sleeves; socks), braces and tapes were grouped as Wearable Garments (WGSS). Textured insoles and footwear were grouped as Textured Materials (TMSS). Last, implementation of white noise and electrical stimulation were grouped as an application of Stochastic Resonance (SRSS).
The methodological quality of the included studies was assessed by two reviewers (lead author and the fourth author) using the Cochrane Collaborations tool for evaluating the risk of bias [
For the systematic review, the extracted data included: sample size, participant characteristics, tasks, equipment used, balance-related measurements and main outcomes of the study. Only studies that reported the outcome measures of interest (CoP related measurements) were included in the statistical analysis. The CoP related data was used due to its commonality in postural control and regulation research [
The primary analysis was to compare the effectiveness of the three different lower-limb stimulation strategies—Wearable garments, Textured materials, and application of Stochastic Resonance. Unbiased (Hedges’
For dependent group designs, effect size estimates for lower-limb stimulation strategies for the control group in each study were standardized using the control group standard deviation value [
Calculated synthesized (by average) estimated effect size and standard error (SE) values were imported into Review Manager (RevMan computer program, version 5.3.5 Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2014) for the calculation of pooled effect size, p-value, z- value, Tau2, heterogeneity (I2). The following settings were used: data type—generic inverse variance; statistical method—inverse variance; analysis model—random effects; effect measure—standardized mean difference (SMD); study and total confidence interval– 95%. An effect size of 0.1 is considered small, an effect size of 0.3 is medium, and an effect size of 0.5, large [
Consequently, pooled effect size, 95% confidence interval, P-value and heterogeneity (I2) were calculated per subgroup, per study. An alpha level of .05 (two-tailed) was used to test whether the average effect size was significantly different from zero in each subgroup.
The subgroup analysis was used to derive pooled estimates of the three subgroups (WGSS; TMSS; SRSS) for the differences observed on postural control performances. Three main areas identified for subgroup comparison were: i) static balance tasks—single-leg standing (SLS) and double-limbs standing (DLS); ii) populations—young and healthy adults, older adults, lower-limb injuries individuals (e.g. Ankle sprained; Anterior Cruciate Ligament reconstruction; Knee Osteoarthritis); and iii) vision availability—eyes open and -closed. There is always some debate over the measurements of postural sway to express system stability. In the meta-analysis of this review, decreases in CoP measurements imply the increased ability of a postural-regulation system to maintain balance. Hence, a positive effect size indicated a functional role of stimulation strategies, while a negative effect size inferred that there was a positive functional capacity of the control group in regulating posture.
Of the 49 studies (
A summary of the characteristics of all included studies was tabulated according to the three different lower-limb stimulation strategies and presented, based on participant characteristics (
Lower limbs' strategies | Study | Young Healthy Adults | Middle-aged and older adults | Neuropathy patients | Athlete / Elite | Lower limbs' Injuries or medical condition | Remarks |
---|---|---|---|---|---|---|---|
Wearable Garments | Birmingham et al. (2001) | √ | |||||
Broglio et al. (2009) | √ | ||||||
Cavanaugh et al. (2016) | √ | ||||||
Genthon et al. (2010) | √ | ||||||
Gribble et al. (2010) | √ | ||||||
Hadadi et al (2011) | √ | √ | |||||
Hadadi et al. (2014) | √ | √ | |||||
Hijmans et al. (2009) | √ | √ | |||||
Kunzler et al. (2013) | √ | ||||||
Kuster et al. (1999) | √ | ||||||
Michael et al. (2014) | √ | ||||||
Ozer et al. (2009) | √ | ||||||
Palm et al. (2012) | √ | ||||||
Papadopoulos et al. (2007) | √ | ||||||
Sperlich et al. (2013) | √ | ||||||
Vuillerme & Pinsault (2007) | √ | ||||||
Wheat et al. (2014) | √ | ||||||
Woo et al. (2014) | √ | ||||||
Textured Materials | Aruin & Kaneka. (2013) | √ | |||||
Collings et al. (2015) | √ | ||||||
Corbin et al. (2007) | √ | ||||||
Hatton et al. (2009) | √ | ||||||
Hatton et al. (2011) | √ | ||||||
Hatton et al. (2012) | √ | ||||||
Jenkins et al. (2009) | √ | √ (PD) | |||||
Kelleher et al. (2010) | √ | √ (MS) | |||||
Ma et al. (2016) | √ | ||||||
Maki et al. (1999) | √ | √ | |||||
Menz et al. (2006) | √ | √ | √ | ||||
Palluel et al. (2008) | √ | √ | |||||
Palluel et al. (2009) | √ | √ | |||||
Perry et al. (2008) | √ | ||||||
Qiu et al. (2012) | √ | √ | |||||
Qiu et al. (2013) | √ | √ (PD) | |||||
Qu (2015) | √ | ||||||
Stern & Gottschall (2012) | √ | ||||||
Wilson et al. (2008) | √ (middle-aged) | Mean age: 51.1±5.8 | |||||
Stochastic Resonance | Amiridis et al. (2005) | √ | |||||
Collins et al. (2012) | √ | √ (Knee Osteoarthritis) | |||||
Dickstein et al. (2005) | √ | ||||||
Gravelle et al. (2002) | √ | ||||||
Kimura & Kouzaki (2013) | √ | ||||||
Magalhaes & Kohn (2012) | √ | ||||||
Magalhaes & Kohn (2014) | √ | ||||||
Ross (2007) | √ | ||||||
Ross & Arnold (2012) | √ | ||||||
Ross & Guskiewicz (2006) | √ | √ | |||||
Ross et al. (2007) | √ | ||||||
Ross et al. (2013) | √ |
Lower limbs' strategies | Study | Static | Dynamic | Gait | |||||
---|---|---|---|---|---|---|---|---|---|
SLS | DLS | Tandem Stance | Unstable/ moving platform (SLS); SEBT | Single leg land_Jump/hop | Stable | Uneven | Hill | ||
Wearable Garments | Birmingham et al. (2001) | √ |
√ | ||||||
Broglio et al. (2009) | √ |
√ |
√ |
||||||
Cavanaugh et al. (2016) | √ (SEBT) | √ | |||||||
Genthon et al. (2010) | √ |
||||||||
Gribble et al. (2010) | √ | ||||||||
Hadadi et al (2011) | √ |
||||||||
Hadadi et al (2014) | √ (SEBT) | ||||||||
Hijmans et al. (2009) | √ |
||||||||
Kunzler et al. (2013) | √ |
||||||||
Kuster et al. (1999) | √ | ||||||||
Michael et al. (2014) | √ |
||||||||
Ozer et al. (2009) | √ | ||||||||
Palm et al. (2012) | √ | ||||||||
Papadopoulos et al. (2007) | √ |
||||||||
Sperlich et al. (2013) | √ | ||||||||
Vuillerme & Pinsault (2007) | √ |
||||||||
Wheat et al. (2014) | √ |
||||||||
Woo et al. (2014) | √ |
||||||||
Textured Materials | Aruin & Kaneka. (2013) | √ |
√ | √ | |||||
Collings et al. (2015) | √ | ||||||||
Corbin et al. (2007) | √ |
√ |
|||||||
Hatton et al. (2009) | √ |
||||||||
Hatton et al. (2011) | √ |
||||||||
Hatton et al. (2012) | √ |
√ | |||||||
Jenkins et al. (2009) | √ | ||||||||
Kelleher et al. (2010) | √ | ||||||||
Ma et al. (2016) | √ | ||||||||
Maki et al. (1999) | √ | ||||||||
Menz et al. (2006) | √ |
||||||||
Palluel et al. (2008) | √ |
√ | |||||||
Palluel et al. (2009) | √ |
||||||||
Perry et al. (2008) | √ | ||||||||
Qiu et al. (2012) | √ |
||||||||
Qiu et al. (2013) | √ |
||||||||
Qu (2015) | √ |
||||||||
Stern & Gottschall (2012) | √ | √ | |||||||
Wilson et al. (2008) | √ |
√ | |||||||
Stochastic Resonance | Amiridis et al. (2005) | √ |
√ |
√ |
|||||
Collins et al. (2012) | √ |
||||||||
Dickstein et al. (2005) | √ |
||||||||
Gravelle et al. (2002) | √ |
||||||||
Kimura & Kouzaki (2013) | √ |
||||||||
Magalhaes & Kohn (2012) | √ |
||||||||
Magalhaes & Kohn (2014) | √ |
||||||||
Ross (2007) | √ |
||||||||
Ross & Arnold (2012) | √ | ||||||||
Ross & Guskiewics. (2006) | √ | ||||||||
Ross et al. (2007) | √ |
||||||||
Ross et al. (2013) | √ |
√ |
* Vision: eyes open;
**Vision: eyes-closed;
***Vision: eyes open and closed;
# Surface: stable;
## Surface: stable and foam
From
Most studies in WGSS and TMSS groupings were at high risk of bias for selection bias, performance, and detection categories (
Overall, about 67% of the studies (n = 33) met the criteria for high risk of bias in the sequence generation category. Of the 33 studies, SRSS had the least number of studies (n = 5; 15.2%) followed by TMSS (n = 11; 33.3%) and WGSS (n = 17; 51.5%). In the WGSS group, all 17 studies (100%) included a non-random approach for selection of participants. There were 24 studies meeting criteria for high risk of bias in the allocation concealment category. Of the 24 studies, 13 from WGSS (54.2%), 8 from TMSS (33.3%) and 3 from SRSS (12.5%).
With regards to the blinding categories, a high risk of bias was found in both the WGSS and TMSS groups– 13 (61.9%) and 6 (28.6%) out of 21 studies, respectively. However, it is important to acknowledge the challenge faced when attempting to blind participants and researchers to intervention materials that are perceivable, especially in WGSS and TMSS groups.
In contrast, most studies (~75.5%) were at as low risk of bias in the participant attrition and reporting categories, with no missing outcome data, with all the relevant dependent variables apparently reported. However, two studies each from WGSS [
Eight studies were rated at a high risk of reporting bias because they failed to report the key outcomes or provided incomplete information on dependent variables [
Overall, a total of 30 studies (WGSS = 9; TMSS = 11; SRSS = 10) reported positive effects of applying lower-limb stimulation strategies on static balance tasks, dynamic balance tasks and gait (
Of the 7 studies in this grouping, six found that braces, tapes and compression sleeves improved postural regulation especially in participants with lower-limb injuries [
For the young and healthy adults, Kunzler et al. [
There were two studies that reported no significant differences in postural regulation with compression bandages and stockings for older adults [
A total of 10 studies examined TMSS effects on postural regulation in static and dynamic balance tasks in young and healthy adults. Five studies reported beneficial effects during performance in DLS balance tasks [
For middle-aged and older adults, 63.6% (7 out of 11) of the studies indicated that textured insoles had a positive influence on static balance control [
There was a unique study that examined the effects of using Velcro, an affordable and innovative approach to providing tactical stimulation, on three groups of participants—young and healthy adults, older adults, and diabetic peripheral neuropathy patients [
Ten out of twelve studies (83.3%) concluded that application of SR had a significant effect on postural regulation in young and healthy adults [
Only one study did not find a significant improvement in performance on a single-leg standing task with sub-threshold electrical stimulation in older adults with minimal-to-moderate knee osteoarthritis [
Among the included studies, 28 studies reported CoP measurement outcomes for the static balance tasks and were included in meta-analysis. The subgroups are wearable garments (n = 10), textured materials (n = 10) and application of SR (n = 8) as lower-limb stimulation strategies. For the static balance tasks, CoP measurements such as time-to-stabilization, path length, the postural sway velocity and distance in both Anterior-posterior (AP) and medial-lateral (ML) directions under the different vision (e.g., eyes open and closed) and surface (stable & foam) conditions were included in the analysis. For the sample populations (young and healthy adults, elderly individuals, and with lower-limb injuries), the CoP measurements from SLS and DLS under the stable surface condition with eyes open and -closed were included in the analysis. For the vision conditions, CoP measurements of all populations, which performed both SLS and DLS under the stable surface, were included in the analysis. Both SLS and DLS comprise popular experimental paradigms used by researchers. The reasons for their popularity could be due to the complex sensory information perceptual mechanisms used during upright stance. It could also due to the association between DLS and the risk of falling, especially in elderly population [
Ten studies (WGSS = 5; SRSS = 5) reported CoP measurements of postural regulation during performance of the SLS task (
Task: Single-Leg Stand; Vision: Eyes open and closed; Surface: Stable and foam; Population: Healthy young; Older adults; Lower-limbs’ injuries.
For the DLS balancing task, a total of 20 studies (WGSS = 5; TMSS = 10; SRSS = 5) were included for analysis (
Task: Double-limbs standing; Vision: Eyes open and closed; Surface: Stable and foam; Population: Healthy young; Older adults; Lower-limbs’ injuries.
In summary, the SRSS is more effective intervention strategy compared to TMSS and WGSS under the SLS and DLS conditions.
A total of 16 studies (WGSS = 6; TMSS = 6; SRSS = 4) that involved young and healthy adults, were included in the analysis (
Population: Young and healthy; Vision: Eyes open and closed; Surface: Stable; Task: Single-leg and double-limbs standing tasks.
For the elderly individuals, a forest plot (
Population: Older adults; Vision: Eyes open and closed; Surface: Stable; Task: Single-leg and double-limbs standing tasks.
There were no differences across the lower-limb stimulation interventions on postural regulation during performance of static balance tasks on a stable surface with eyes open and eyes-closed (
Population: Lower-limbs’ injuries; Vision: Eyes open and closed; Surface: Stable; Task: Single-leg and double-limbs standing tasks.
In summary, the SRSS showed beneficial effects on postural regulation in all three populations. In contrast, the WGSS induced adverse effects in an elderly population.
A significant negative pooled effect size observed in the WGSS sub-group (SMD = -0.21, z = 2.09, p = 0.04) during static balancing tasks performed by participants on a stable surface under the eyes open condition (
Vision: Eyes open; Surface: Stable; Task: Single-leg and double-limbs standing tasks; Population: Healthy young; Older adults; Lower-limbs’ injuries.
A negative pooled effect size was observed in the WGSS sub-group (SMD = -0.16, z = 0.61, p = 0.54) for the static balance tasks performed by participants on a stable surface under the eyes closed condition (
Vision: Eyes- closed; Surface: Stable; Task: Single-leg and double-limbs standing tasks; Population: Healthy young; Older adults; Lower-limbs’ injuries.
In summary, WGSS did not have any beneficial effects for performance in the static standing task on a stable surface under both vision conditions. In contrast, SRSS & TMSS showed beneficial effects under the same conditions.
The primary aim of this quantitative review was to investigate effectiveness of different lower- limb sensory stimulation strategies on postural regulation through systematic review and meta-analysis. Of additional interest was the comparison of effects with respect to three major subgroupings in the extant literature—WGSS, TMSS and SRSS in various populations (young and healthy; older adults; individuals with lower- limb injuries) and under different task and informational constraints (Unipedal; Bipedal; Eyes open; Eyes -closed). To the best of our knowledge, this is the first systematic review and meta-analysis comparing the effectiveness of various lower-limb stimulation strategies on postural regulation performance in different sub -populations.
Qualitative and quantitative analyses of SRSS studies showed significant positive effects of applying a SR strategy in young and healthy adults during static balance tasks (SLS & DLS) and in a vision condition. In contrast, a quantitative analysis of WGSS effectiveness showed no, or adverse, effects in older adults, young and healthy populations, during performance of static balance tasks (SLS & DLS), with eyes open and closed conditions. However, the qualitative analysis demonstrated some beneficial effects of using WGSS such as braces, tapes and compression sleeves. The quantitative and qualitative analyses suggested that TMSS studies revealed small and moderate positive effects of wearing textured materials on postural regulation during static and dynamic balance tasks.
Qualitative data suggested that wearable garments provide additional somatosensory information, inducing cutaneous pressure, probably by enhancing stimulation of plantar cutaneous receptors in the lower limbs [
Only two studies, by Kunzler et al. [
Studies by Hijmans et al. [
The qualitative review showed that double-limb standing balance measurements were most commonly used in studies of textured materials. Additionally, participants were almost always older adults. The quantitative review showed that textured insoles enhanced postural regulation performance in challenging conditions—during upright balance with eyes closed on a stable surface (SMD = 0.61), in older adults (SMD = 0.30).
The motivations behind these studies are rooted in ideas of deterioration of sensory system performance and the concept of sensory systems re-weighting their contributions to action regulation. Changes in cutaneous sensitivity and receptor morphology have been observed as people age, and have been associated with a reduction in neural activity, which increases the sensory and vibration threshold needed for accurate perception [
From the perspective of sensory re-weighting, individuals primarily rely on the somatosensory inputs when visual information is unavailable [
Of the 4 studies [
It is also worth noting that the TMSS was the only lower-limb stimulation strategy not used to investigate the effects of textured materials on participants with lower-limb injuries. Previous studies have revealed beneficial effects seen in DLS task performance in other populations. It is plausible that people with lower-limb injuries could benefit from using the textured materials to help their balance and postural control. The findings of this systematic review and meta-analysis suggest that textured materials could be potentially used as a medium to ameliorate negative effects on the postural control system due to aging.
The qualitative analysis showed that 83.3% of the studies reported that imperceptible electrical stimulation (white noise, 0.01mA– 0.05mA) enhanced balance control, being associated with reduced postural sway during performance in static balance tasks. This stimulation strategy showed moderate- to high-pooled effect sizes in most of the populations and categories studied—young and older adults, healthy individuals, static balance tasks, and with vision available.
The current quantitative review focused on research studies with a common site of stimulation along the shank, and between the ankle and knee joints. Most of the electrodes were placed on the muscles, ligaments and bone (lateral and medial side of femoral condyles). It is postulated that muscle spindles and mechanoreceptors along the shank were sensitive to the stimulation by SR. Stimulation of these sites yielded beneficial effects on postural regulation in older adults, and in patients with lower limb injuries, as well as healthy young adults. A key difference in studies, noted from the review, concerns variations in the sites of stimulation, focusing on particular receptor(s). The majority of the studies in the WGSS grouping applied wearable garments at the ankle joint (targeting joint receptors). The soles of the feet (cutaneous receptors) were the most common stimulation sites used in TMSS studies. For the SRSS research, the site of stimulation was typically between the knee and the shank (targeting muscle spindles; mechanoreceptors). With the moderate to high effect sizes reported in the SRSS studies, investigators might wish to consider other sites of stimulation in future WGSS and TMSS studies.
The direct application of weak input signals (non-zero level of noise) enhanced the detection of sensorimotor signals, which were beneficial to motor task performance (e.g., balance) [
Of three studies [
A limitation of this review is that some outcomes included summary values extracted from graphs when values were not reported, reflecting estimations of the treatment effects. This review solely focused on research that had undergone rigorous, external peer review in international, scientific journals. The varied intervention periods in the 4 studies included in the meta-analysis might have had some impacts on the overall effects of the respective lower-limb stimulation strategies.
The findings of this review suggest three possible areas for future research. First, this review suggests that WGSS, TMSS and SRSS applications could be extended to the study of older adults, people with lower-limb injuries, as well as with elite and developing athletes, since many sports require attunement to information from the lower limbs for successful performance. Second, task performance difficulty levels need to be included in future analyses of experimental effects, such as the use of unstable surfaces in an eyes-closed condition and walking on uneven surfaces to measure the effectiveness of the lower-limb stimulation strategies. Third, at a later stage, there is a need to study effects of integrating two lower-limb stimulation strategies such as wearing textured and compression materials (or analysing the relative influence of different compression levels [clinical and non-clinical levels]) on the somatosensory system function in sports and clinical settings, particularly for developing athletes and in people with significant sensory function disorders.
A review of current evidence in published literature indicates that an SRSS has produced the most effective results in postural regulation, compared to implementing interventions with wearable garments and textured materials. An SRSS achieved moderate to high effect size in all the populations and task constraints studied—healthy young and older adults, single-leg and double-limbs standing balance tasks and eyes open condition. Regardless of these differences, the costs of the organising specific interventions also need to be considered. The review revealed that the WGSS was effective in studies of patients with lower-limb injuries, and TMSS was found to be beneficial in young and healthy population in a double-leg standing task. Future research can consider to investigate the effects of textured materials in populations with lower limb injuries during performance on a single- leg standing task. The usage of SRSS and WGSS could be extended out to neuropathy patients and elderly population respectively. Furthermore, researchers could use at least two of the currently used stimulation strategies in combination as an intervention treatment for people with significant sensory function disorders, or for the enhancement of skill and expertise in elite and developing athletes. The combination of two stimulation strategies might yield better results by enhancing the sensorimotor signals to the nervous system to support performance.
(DOC)
(DOCX)