Effect of attention focus on acquisition and retention of postural control following ankle sprain

Effects of External and Internal Focus of Attention Exercises in Chronic Low Back Pain: A Randomized Controlled Trial

AIM

Balance, physical performance, and functional parameters are adversely affected in individuals with chronic low back pain (CLBP). The focus of attention can affect balance and performance. Our aim is to compare the effects of focus of attention instructions given to dynamic balance exercises on balance, physical performance, and functional status in individuals with CLBP.

DESIGN

A randomized controlled trial.

METHODS

Of 53 individuals with CLBP, 44 individuals who met the inclusion criteria were divided into two groups: the external focus group (EFG) and the internal focus group (IFG). Traditional physiotherapy methods and dynamic balance exercises were applied to both groups. External focus (EF) instructions were given to the EFG, and internal focus (IF) instructions were given to the IFG during the dynamic balance exercises. Participants before and after the treatment were evaluated for pain, functional level, balance, physical performance, and posture.

RESULTS

The results of the study showed greater improvement in EFG on dynamic balance, fall risk, stability limits, physical performance, posture, spinal mobility, and postural endurance (p < .05).

CONCLUSIONS

This study showed that external focusing was more effective than internal focusing on balance, performance, and posture in individuals with CLBP.

Acquisition, Retention, and Transfer Effects of Landing Training to Increase Foot Progression Angle During Bilateral Drop Landings

Foot position during landing directly influences knee mechanics. Thus, the purpose of this study was to determine success in practicing, repeating, and transferring a desired foot progression angle (FPA) during landing, as well as changes in knee mechanics. Twenty females were randomly assigned to a control or verbal instruction group. On day 1, each group performed 40 drop landings. The verbal instruction group was instructed to "Land with 30 degrees of external rotation" before every trial. Feedback was provided on a terminal schedule in the form of knowledge of FPA error. On day 2, retention was assessed with 5 drop landings, while transfer was assessed during a 2-step stop-jump landing. Repeated-measures analyses of variance (2 × 4 [group × time]) were used to assess the influence of verbal instruction on knee mechanics. Participants who received verbal instruction exhibited increased FPA. They also demonstrated increased initial contact knee abduction during acquisition and retention. For all participants, initial contact knee flexion increased, while peak knee adduction moment decreased during acquisition. While the verbal instruction cue was effective in promoting an increase in FPA and reducing some ACL injury risk factors during practice and retention, this cue may only be effective to tasks similar to what was practiced.

Effects of dual-task training on chronic ankle instability: a systematic review and meta-analysis

BACKGROUND

Dual-task training has been a popular intervention for individuals with balance impairments. However, the effects of dual-task training on chronic ankle instability (CAI) have not been comprehensively analyzed and reliable clinical evidence is scarce. The purpose of this systematic review and meta-analysis is to evaluate the effectiveness of dual-task training on postural stability and functional ability in individuals with CAI.

METHODS

PubMed, Web of Science, EBSCO, Cochrane Library, Physiotherapy Evidence Database (PEDro), and China National Knowledge Infrastructure (CNKI) were researched from inception to November 2022. This study was conducted by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Two reviewers assessed the studies for inclusion and extracted data. The Cochrane Risk of Bias list was used to assess the risk of bias in included studies. Mean differences (MD) with a 95% confidence interval (CI) were calculated with the RevMan 5.3 software.

RESULTS

A total of 7 randomized controlled trials with 192 CAI met the inclusion criteria. The meta-analysis results showed that compared with the control group, dual-task training significantly improved the Y-balance test (MD = 1.60, 95% CI: -0.00 to 3.21, P = 0.050) and reduced COP-area (MD = - 0.94, 95% CI: -1.62 to - 0.26, P = 0.007) in individuals with CAI. However, there is no significant difference between dual-task training and the control group on COP-velocity (MD = - 0.26, 95% CI: -0.70 to 0.17, P = 0.240), hop test (MD = - 0.20, 95% CI: -0.66 to 0.26, P = 0.386) and BESS (MD = - 1.24, 95% CI: -2.95 to 0.48, P = 0.157) in individuals with CAI.

CONCLUSION

This meta-analysis showed that dual-task training may be effective in improving static and dynamic postural stability. However, more high-quality randomized controlled trials are needed to verify the short and long-term effectiveness of dual-task training on CAI.

Every story has two sides: evaluating information processing and ecological dynamics perspectives of focus of attention in skill acquisition

Directing our focus of attention appropriately during task execution can benefit outcome performance, cognitive efficiency, and physiological efficiency. For instance, individuals may benefit from adopting an external focus of attention (i.e., by focusing attention on the effects of one's movements on the environment) over an internal focus of attention (e.g., focusing on one's body movements). However, accounts concerning the theoretical functioning of such effects have primarily relied on hierarchical information processing perspectives; far less consideration has been given to potentially alternative explanations based on ecological dynamics, instances where an internal focus may be desirable over an external focus, and the associated applied implications. Within the present review, we: (a) outline the most recent developments in attentional focus research; (b) evaluate similarities and differences between information processing and ecological dynamics explanations of the focus of attention effect; (c) provide practical recommendations; and (d) discuss future research avenues. In doing so, a case is made for an "Ecological Dynamics Account of Attentional Focus" to act as an alternative to information processing-based hypotheses.

Protocol for double-blinded randomized trial to enhance postural control after anterior cruciate ligament reconstruction by balance training and concurrent cognitive demands or external focus of attention

Anterior cruciate ligament (ACL) injury is one of the most common injuries among athletes that lead to postural control disorders. The aim of this study is to compare the effects of balance training with and without cognitive task and external focus of attention on postural control in individuals with ACL reconstruction. Sixty participants with ACL reconstruction, between the ages of 18 and 47 will be randomly allocated to three group's including routine balance training, balance training with external focus of attention. Patients will be assessed at the baseline, after receiving eight weeks of intervention, and four weeks later. A double-blinded design will be used. Center of pressure data acquired from a forceplate will be used to assess amount and velocity of sway, local dynamical stability, and global stability of upright balance. Also, dynamic balance will be assessed using Star Excursion balance test. The results of this research will be used to establish effectiveness of treatment strategies for postural control in individuals with anterior cruciate ligament reconstruction. The suggested interventions would be clinically applicable in the athlete with ACL injury.

The Path to Translating Focus of Attention Research Into Canadian Physiotherapy, Part 1: Physiotherapists’ Self-Reported Focus of Attention Use Via a Study-Specific Questionnaire

The focus of attention literature has shown robust findings for the benefits of providing statements that focus on the movement effect or outcome (external focus of attention [EFOA]) as opposed to focusing on the movement kinematics (internal focus of attention). Observational studies, however, have revealed that physiotherapists use fewer EFOA statements than internal focus of attention statements in their practice. Most evidence in this regard has been from non-Canadian physiotherapists working in stroke rehabilitation; consequently, we sought to examine whether Canadian physiotherapists working with various rehabilitation populations also use EFOA statements to a lesser extent than internal focus of attention statements. The “Therapists’ Perceptions of Motor Learning Principles Questionnaire (TPMLPQ)” was thus designed and data from 121 Canadian physiotherapists showed low relative frequencies of EFOA use (31.3% ± 14%) averaged across six hypothetical scenarios. A higher EFOA was reported, however, for two of the six scenarios: a functional reaching scenario (55.5% ± 37.0%) and pelvic floor task (65.6% ±32.9%). This data suggest that the findings of EFOA benefits have not been widely translated into Canadian physiotherapy settings; furthermore, the findings of the scenario-dependency warrant future investigation into factors, such as task characteristics, that may influence physiotherapists’ FOA use.

[Attentional focus instructions for therapeutic exercise in people with musculoskeletal disorders. A scoping review]

Attentional focus instructions are verbal strategies that could maximize the effects of exercise. The objective of this review was to explore and synthesize the available evidence on the incorporation of attentional focus instruction in the exercise of people with musculoskeletal disorders. A search of 11 databases was carried out until October 2020. Of 4,227 studies identified in the searches, 15 were included. The studies showed deficiencies in the conceptualization and definition of attentional focus instructions. The available evidence indicates that external focus is effective in improving motor learning and function. However, methodological limitations, clinical heterogeneity, the small number of articles included, and new experimental studies challenge the conclusions of the systematic reviews available to date. Attentional focus instructions in musculoskeletal disorders is an emerging field and requires further research. This review is a guide for future studies.

Focus of Attention in Voice Training

OBJECTIVE

The vast majority of motor learning studies investigating focus of attention have found that an external focus of attention (focusing on the effect of a movement) results in enhanced performance and learning, compared to an internal focus of attention (focusing on the body movement itself). The present study attempts to determine if the high incidence of internal focus of attention instruction that has been reported in the realm of athletics is replicated in voice training.

METHODS

Two hundred and seventy-eight singers, who were at least 18 years old and taking voice lessons, were recruited to participate in an anonymous research survey entitled "Instructions given to singers in voice lessons." The main six questions asked singers to report phrases or instructions that their studio voice teachers gave them in regard to posture, breathing and/or support, tone clarity and/or onset of tone, space and/or resonance, articulation, and reducing tension.

RESULTS

Approximately 50.83% of the total responses were classified as inducing an external focus, 39.42% were classified as internal focus, 6.48% used a combination of both internal and external focus, and 3.27% were categorized as miscellaneous.

CONCLUSIONS

The results of this study indicate that voice teachers use both external and internal attentional focus directives in the voice studio. Given the robust body of literature supporting the use of external focus, it is noteworthy that the current study found that external focus is used more often than internal focus in voice training.

Dominance of Attention Focus and Its Electroencephalogram Activity in Standing Postural Control in Healthy Young Adults

Attention focus changes performance, and external focus (EF) improves performance compared to internal focus (IF). However, recently, the dominance of attention focus, rather than the effectiveness of unilateral EF, has been examined. Although the positive effects of EF on standing postural control have been reported, the dominance of attention focus has not yet been examined. Therefore, the purpose of this study was to examine the dominance of attention focus and its neural mechanism in standing postural control using electroencephalography (EEG). A standing postural control task under IF and EF conditions was performed on healthy young men. Gravity center sway and cortical activity simultaneously using a stabilometer and an EEG were measured. Participants were classified into IF-dominant and EF-dominant groups according to their index of postural stability. The EEG was analyzed, and cortical activity in the theta-wave band was compared between the IF-dominant and EF-dominant groups. Significant neural activity was observed in the left parietal lobe of the IF-dominant group in the IF condition, and in the left frontal lobe of the EF-dominant group in the EF condition (p < 0.05). Differences in EEG activity between IF-dominant and EF-dominant groups, in standing postural control, were detected. This contributes to the development of training methods that consider attentional focus dominance in postural control.

Empirical Evidence for the Functionality Hypothesis in Motor Learning: The Effect of an Attentional Focus Is Task Dependent

A large body of research suggests that during learning motor skills, focusing on environmental effects of the movement (external focus) generally leads to better performance than focusing on one’s own body (internal focus). The functionality hypothesis states, in contrast, that the superiority of any attentional focus is task dependent. The present study aimed to test the predictions of the latter and searched for underlying mechanisms and task characteristics for one or the other focus being more functional. In Experiment 1, we examined whether the internal focus is superior in a difficult body-oriented balance task. In Experiment 2, we added visual feedback and investigated whether this would enhance the functionality of the external focus. In both experiments, the participants stood one-legged on a balance board and had to shift their centre of pressure (COP) to predefined target points. Per instruction, they were asked to interpret their attentional focus on the COP as either internal (the sole of the foot) or external (the platform). In Experiment 1, the external focus was induced through a mental image. The internal focus group performed significantly better, thereby supporting the functionality hypothesis. In Experiment 2, the COP was dynamically visualized on a screen. The internal focus superiority vanished. We suggest that the internal focus is more functional in motor-learning situations that provide more effect information through body-internal senses than through body-external senses. In these cases, the external focus hampers learning because it is associated with additional cognitive load.

Effective Attentional Focus Strategies after Anterior Cruciate Ligament Reconstruction: A Commentary

Individuals after anterior cruciate ligament reconstruction (ACLR) have a high rate of reinjury upon return to competitive sports. Deficits in motor control may influence reinjury risk and can be addressed during rehabilitation with motor learning strategies. When instructing patients in performing motor tasks after ACLR, an external focus of attention directed to the intended movement effect has been shown to be more effective in reducing reinjury risk than an internal focus of attention on body movements. While this concept is mostly agreed upon, recent literature has made it clear that the interpretation and implementation of an external focus of attention within ACLR rehabilitation needs to be better described. The purpose of this commentary is to provide a clinical framework for the application of attentional focus strategies and guide clinicians towards effectively utilizing an external focus of attention in rehabilitation after ACLR.

LEVEL OF EVIDENCE

5.

Does an Externally Focused Dual-task Mitigate Real-time Conscious Postural Control in Older Adults?

Objectives: This study first examined whether real-time conscious postural control (reinvestment) and postural sway increase with different postural difficulties on a compliant surface among older adults. The second objective was to investigate the effect of an externally focused dual-task on real-time reinvestment and postural sway under a relatively challenging standing position. Method: Thirty-two community-dwelling older adults (mean age = 72.09, SD = 4.18 years) were recruited. Participants performed balance tasks in four standing positions in a randomized order on a balance foam pad. The four positions included wide-based standing on foam (WBF), narrow-based standing on foam (NBF), tandem-based standing on foam (TBF) and tandem-based standing on foam with an externally focused dual-task (TBFE). Throughout all the balance tasks, participants' real-time reinvestment and body sway were indicated by the Alpha2 T3-Fz Electroencephalogram (EEG) coherence and the total sway length (TSL), respectively. Results and Discussion: Our results revealed no significant difference in real-time reinvestment among different standing positions while postural sway increased from WBF to NBF and reduced from NBF to TBF. We also demonstrated that when performing a relatively challenging standing task on a compliant surface, an externally focused dual-task (TBFE), compared to a baseline single task (TBF), can neither mitigate real-time reinvestment nor improve balance performance in community-dwelling older adults with good balance capability. Potential explanations and implications are discussed.

The autonomy and focus of attention strategies under distraction: Frequency and sample entropy analyses in a dynamic balance task

An external focus of attention has been shown to be effective in balance tasks. However, replication in applied settings is limited. The OPTIMAL theory proposes that a combination of autonomy and external focus increases focus to the task goal, and therefore more effective than external focus alone. However, research suggests that the combined effect is limited in discrete skills, and the increased focus effect is only reported by subjective assessment. The present study examined the effect of the combined strategy and its effect of "increased focus" compared to external focus and control groups under distraction. In experiment 1, participants (N = 60) practiced eight 35 s trials on a stabilometer followed by a 10 min-delayed retention test and an auditory distraction transfer test. The combined group chose a tape color to place on a stabilometer and was told to "keep the tapes parallel to the floor," the external focus group was yoked with the combined group, and the control group was told to "do your best". Performance was measured in Root Mean Square Error (RMSE). The increased focus effect was examined by both subjective (distraction score, a question about participants' perceptions) and objective (Mean Power Frequency, MPF, Sample entropy, SampEn) methods. Although participants improved significantly (p < .05), group differences were not observed during retention (p's > 0.05). An increased focus effect of the combined effect was not observed in any variables (p's > 0.05). In experiment 2, the practice duration was extended to replicate previous study designs (i.e., 90s trials; 2 days of practice; 24 h retention test; the number of participants). Consistent with experiment 1, group differences were not evident in RMSE, SampEn, and MPF (p's > 0.05). We suggest that autonomy may be required to be task-relevant, and simply telling to do best may be as useful as external focus or combined strategies in a continuous balance task. Further, the analysis showed that SampEn increased on Day 1 but decreased on Day 2, and MPF decreased within a session, but the average MPF increased by the day. Potential explanations and future directions when utilizing these metrics are discussed.

Effects of Nonelastic Taping and Dual Task on Kinematics and Kinetics of the Ankle Joint

Objectives

The purpose of this experimental study was to investigate the effects of nonelastic taping and dual task on ankle kinematics and kinetics in gait analysis of healthy adults.

Methods

A total of 21 healthy adults completed trials of gait analysis using a Vicon system combining ground walking with different cognitive task conditions (none, modified Stroop color/character naming, and serial-7 subtraction), with or without nonelastic taping. Ankle kinematics and kinetics including speed, ankle plantarflexion and inversion angle, ground reaction force (GRF), and stride time variability (STV) under all conditions of taping (YES or NO) and cognitive task (none, naming, and subtraction) were characterized and analyzed with repeated-measures ANOVA.

Results

As regards cognitive performance, the serial-7 subtraction performance under walking conditions with and without taping was significantly poorer than simple sitting condition (P < 0.001). For kinematics and kinetics, STV showed statistically significant decrease (P=0.02) when subjects underwent taping application. Vertical GRF was significantly greater under taping than barefoot (P=0.001). Ankle plantarflexion at initial contact (IC) under the dual-task walking was significantly more than under simple walking (P=0.008).

Conclusions

Applications of nonelastic taping and dual task may lead to the STV, vertical GRF, ankle plantarflexion, and speed alterations because of restricted joint range of motion and changed sensorimotor neural circuit. When healthy adults performed dual-task walking, central neural resources allocation was disturbed, leading to weakened performance in both motor and cognitive tasks.

Effects of an external focus of attention and target occlusion on performance in virtual reality

The use of virtual reality as a training mechanism continues to gain popularity as equipment becomes more readily available. It is important to not only understand the relationship between virtual reality training and motor learning, but to understand the extent to which practice manipulations enhance performance in virtual reality. One common practice manipulation is adopting an external focus of attention, which has been shown to facilitate motor learning in a variety tasks. The purposes of the present study were to investigate the effectiveness of an external focus of attention and the effects of target occlusion times in virtual reality. Fifty-six participants performed a single-leg long jump during baseline, training, and retention and were randomly assigned to either an external or control group. During baseline and retention, all participants performed the task in both a virtual reality (VR) and real world (RW) environments. Training was all done in VR where participants were provided an external focus cue or no cue. Results revealed that individuals jumped significantly further in RW than VR in both baseline and retention (p < .001). During training, the external group jumped significantly further than control (p < .05). These results suggest that the adoption of an external focus improves performance during training. However, we did not see a benefit of an external focus in retention. These findings should be taken into consideration when using virtual reality as a training tool when performance must be transferred to a real world environment.

Attentional focus influences sample entropy in a balancing task

An external focus of attention has consistently been associated with improved balance (Wulf, 2013). Recent work has considered whether changes in postural control entropy, a measure of repeated movement patterns, could be a factor influencing this benefit. Rheaet al. (2019) reported that during quiet standing sample entropy when using an external focus was increased relative to baseline, whereas an internal focus did not differ from baseline. External and internal focus conditions did not differ from each other, but the authors speculated this difference may emerge with more complex balance tasks. The purpose of the present study was to determine if sample entropy and standard deviation of angular displacement differed when balancing on a stability platform while using an external, internal, or holistic focus. Young healthy adults (N = 36) completed three familiarization trials on the stability platform, followed by three trials each using an external focus (focus on keeping markers level), an internal focus (focus on keeping feet level), and a holistic focus (focus on feeling calm and stable). All trials lasted 20 s, and focus condition order was counterbalanced. Angular displacement of the platform was recorded at a frequency of 25 Hz, and sample entropy and standard deviation of angular displacement were calculated using a custom MATLAB code. Separate mixed ANOVAs for each dependent variable were used to assess differences due to focus and condition order, and Sidak post-hoc tests were used for pairwise comparisons. Results indicated an external focus led to higher sample entropy than a holistic focus (p = .001) and internal focus (p = .031). Standard deviation trended toward lower values with an external focus, but was influenced by a Focus x Order interaction. These results suggest that an external focus may promote more adaptive movement adjustments relative to a holistic focus and an internal focus.

Principles of Motor Learning to Support Neuroplasticity After ACL Injury: Implications for Optimizing Performance and Reducing Risk of Second ACL Injury

Athletes who wish to resume high-level activities after an injury to the anterior cruciate ligament (ACL) are often advised to undergo surgical reconstruction. Nevertheless, ACL reconstruction (ACLR) does not equate to normal function of the knee or reduced risk of subsequent injuries. In fact, recent evidence has shown that only around half of post-ACLR patients can expect to return to competitive level of sports. A rising concern is the high rate of second ACL injuries, particularly in young athletes, with up to 20% of those returning to sport in the first year from surgery experiencing a second ACL rupture. Aside from the increased risk of second injury, patients after ACLR have an increased risk of developing early onset of osteoarthritis. Given the recent findings, it is imperative that rehabilitation after ACLR is scrutinized so the second injury preventative strategies can be optimized. Unfortunately, current ACLR rehabilitation programs may not be optimally effective in addressing deficits related to the initial injury and the subsequent surgical intervention. Motor learning to (re-)acquire motor skills and neuroplastic capacities are not sufficiently incorporated during traditional rehabilitation, attesting to the high re-injury rates. The purpose of this article is to present novel clinically integrated motor learning principles to support neuroplasticity that can improve patient functional performance and reduce the risk of second ACL injury. The following key concepts to enhance rehabilitation and prepare the patient for re-integration to sports after an ACL injury that is as safe as possible are presented: (1) external focus of attention, (2) implicit learning, (3) differential learning, (4) self-controlled learning and contextual interference. The novel motor learning principles presented in this manuscript may optimize future rehabilitation programs to reduce second ACL injury risk and early development of osteoarthritis by targeting changes in neural networks.

Motor Behavior Concepts in the Study of Balance: A Scoping Review

Previous research suggests that using Fitts' law; attentional focus or challenge point framework (CPF) is beneficial in balance control studies. A scoping review was conducted to examine studies that utilized these motor behavior concepts during balance control tasks. An extensive literature search was performed up to January 2018. Two independent reviewers conducted a study selection process followed by data extraction of the search results. Forty-six studies were identified, with 2 studies related to CPF, 12 studies related to Fitts' law and 32 studies related to focus of attention. The CPF appears to be a useful method for designing a progressive therapeutic program. Fitts' law can be used as a tool for controlling the difficulty of motor tasks. Focus of attention studies indicate that adopting an external focus of attention improves task performance. Overall, studies included in this review report benefit when using the selected motor behavior concepts. However, the majority (>80%) of studies included in the review involved healthy populations, with only three clinical trials. In order to ascertain the benefits of the selected motor behavior concepts in clinical settings, future research should focus on using these concepts for clinical trials to examine balance control among people with balance impairments.

Changing one's focus of attention alters the structure of movement variability

Substantial evidence supports the beneficial effect of an external (vs. internal) focus of attention on task performance during goal-directed movements. Counter-intuitively, an external focus has also been shown to increase joint-level movement variability.

OBJECTIVE

To determine whether shifting attentional focus can alter the structure of movement variability, thereby offering a probable mechanistic explanation for how adopting an external focus of attention might confer its benefits.

METHODS

Thirty-five healthy adults (age 23-55) performed unipedal hopping under three different attentional foci: natural (no directed focus), internal focus, and external focus. Uncontrolled manifold analysis was used to examine the structure of movement variability with respect to stabilization of leg orientation and vertical leg length during hopping. Takeoff/landing event bin and stance phase integrals of performance-irrelevant and performance-destabilizing variability were compared across focus conditions.

RESULTS

Accuracy of hopping in place improved with both external and internal foci compared to the natural condition (.004 ≤ p ≤ .035). External focus, to a greater degree than internal focus, destabilized leg orientation at takeoff and landing compared to the natural condition (.001 ≤ p ≤ .038). External focus increased - but internal focus decreased - leg length stabilization throughout stance compared to the natural condition (p < .001).

CONCLUSION

External focus was superior to internal and natural focus conditions in terms of increasing flexibility within the system to orient the leg differently at takeoff and landing to compensate for unintentional drift during hopping. An external focus increased leg length stabilization in stance by preferentially increasing the subset of variability that explores multiple successful performance options. These results provide an understanding of the mechanism underlying external focus benefits - improving movement variability/coordination.

Effect of Attentional Focus Instructions on Motor Learning and Performance of Patients with Central Nervous System and Musculoskeletal Disorders: a Systematic Review

Exercise is one of the main rehabilitative interventions, commonly used to improve performance and motor learning. During the application of attentional focus strategies, External Focus of Attention (EFA) aiming at the movement effect has been reported to have more efficacy than Internal Focus of Attention (IFA) aiming at movement characteristics in healthy subjects. There are not many studies that compare the EFA and IFA instructions in people with Musculoskeletal (MSK) and Central Nervous System disorders (CNS). The purpose of this systematic review is to determine if IFA or EFA, in patients with CNS or MSK, may improve performance and have some effects on motor learning. Databases used for research: PubMed, CINAHL, Cochrane Library, PEDro, PsycINFO, SCOPUS. Inclusion criteria: Randomized Controlled Trial, quasi-Randomized Controlled Trial, enrolled subjects with CNS or with MSK and compared the efficacy of EFA and IFA. The studies suggest that the EFA is better than IFA in affecting the movement execution in patients with MSK, while conflicted findings emerge in presence of CNS disorders. Studies included in the qualitative analysis showed heterogeneous methodological features in study design and conductance, so results must be interpreted with caution.

Surgical management of chronic lateral ankle instability: a meta-analysis

Background

A key point to surgical treatment of chronic lateral ankle instability is choosing a suitable surgical procedure. The purpose of this meta-analysis was to compare different surgical techniques for management of chronic lateral ankle instability.

Methods

We searched the Cochrane Library, MEDLINE, and EMBASE. All identified randomized and quasi-randomized controlled trials of operative treatment for chronic lateral ankle instability were included. Two review authors independently extracted data from each study and assessed risk of bias. Where appropriate, results of comparable studies were pooled.

Results

Seven randomized controlled trials were included for analysis. They fell in five clearly distinct groups.

One study comparing two different kinds of non-anatomic reconstruction procedures (dynamic and static tenodesis) found two clinical outcomes favoring static tenodesis: better clinical satisfaction and fewer subsequent sprains.

Two studies compared non-anatomic reconstruction versus anatomic repairment. In one study, nerve damage was more frequent in non-anatomic reconstruction group; the other one reported that radiological measurement of ankle laxity showed that non-anatomic reconstruction provided higher reduction of talar tilt angle.

Two studies comparing two anatomic repairment surgical techniques (transosseous suture versus imbrication) showed no significant difference in any clinical outcome at the follow-up except operation time.

One study compared two different anatomic repairment techniques. They found that the double anchor technique was superior with respect to the reduction of talar tilt than single anchor technique.

One study compared an anatomic reconstruction procedure with a modified Brostrom technique. Primary reconstruction combined with ligament advanced reinforcement system results in better patient-scored clinical outcome, at 2 years post-surgery, than the modified Brostrom procedure.

Conclusions

There is limited evidence to support any one surgical technique over another surgical technique for chronic lateral ankle instability, but based on the evidence, we could still get some conclusions: (1) There are limitations to the use of dynamic tenodesis, which obtained poor clinical satisfaction and more subsequent sprains. (2) Non-anatomic reconstruction abnormally increased inversion stiffness at the subtalar level as compare with anatomic repairment. (3) Multiple types of modified Brostrom procedures could acquire good clinical results. (4) Anatomic reconstruction is a better procedure for some specific patients.

Electronic supplementary material

The online version of this article (10.1186/s13018-018-0870-6) contains supplementary material, which is available to authorized users.

The Influence of Attentional Focus on Balance Control over Seven Days of Training

This study examined the training effect of attentional focus (external focus, internal focus, or no focus instructions) on a dynamic balance task. Participants completed baseline balance testing, seven consecutive days of dynamic balance board training, and retention testing 24 hours after the last session. The novel finding of this study was the presence of a training effect on balance control when adopting an external focus relative to an internal focus or no focus instructions. Further, we report the unique observation that more patterned behavior was adopted regardless of the focus instructions. These findings provide insight into how instructions can be altered to enhance human balance control and complement the constrained-action hypothesis.

Implicit video feedback produces positive changes in landing mechanics

BACKGROUND

Implicit (IF) and explicit (EF) feedback are two motor learning strategies demonstrated to alter movement patterns. There is conflicting evidence on which strategy produces better outcomes. The purpose of this study was to examine the effects of reduced IF and EF video feedback on lower extremity landing mechanics.

METHODS

Thirty participants (24 ± 2 years, 1.7 ± 0.1 m, 70 ± 11 kg) were randomly assigned to three groups: IF (n = 10), EF (n = 10), and control (CG) (n = 10). They performed twelve box-drop jumps three times a week on the training sessions for six weeks. Only IF and EF groups received video feedback on the training sessions. IF was cued to focus their attention on the overall jump, while EF was cued to focus on position of their knees. 3D lower extremity biomechanics were tested on testing sessions with no feedback. All sessions were at least 24 h apart from another. Testing sessions included baseline testing (pretest), testing after 3 training sessions with 100% feedback (pst1), testing after 6 training sessions with 33.3% feedback (pst2), testing after 6 training sessions with 16.6% feedback (Pst3), and testing 1 month after with no feedback (retention - ret). ANOVA compared differences between groups and time at initial contact and peak for hip flexion (HF, °) and abduction angle (HA, °), hip abduction moment (HAM, Nm/kgm), knee flexion (KF, °) and abduction angle (KA, °), knee abduction moment (KAM, Nm/kgm) and VGRF (N) (p < 0.05).

RESULTS

A significant main effect for group was found between IF and EF groups for HA (IF = - 6.7 ± 4; EF = - 9.4 ± 4.1) and KAM (IF = 0.05 ± 0.2; EF = - 0.07 ± 0.2) at initial contact, and peaks HA (IF = - 3.5 ± 4.5; EF = - 7.9 ± 4.7) and HAM (IF = 1.1 ± 0.6; EF = 0.9 ± 0.4). A significant main effect for time at initial contact for HF (pre = 32.4 ± 3.2; pst2 = 36.9 ± 3.2; pst3 = 37.9 ± 3.7; ret. = 34.1 ± 3.7), HAM (pre = 0.1 ± 0.1; pst1 = 0.04 ± 0.1; pst3 = 0.1 ± 0.01), KA (pre = 0.7 ± 1.1; pst1 = 0.2 ± 1.2; pst3 = 1.7 ± 1), and KAM (pre = 0.003 ± 0.1; pst3 = 0.01 ± 0.1) was found.

DISCUSSION/CONCLUSION

We found that implicit feedback produced positive changes in landing mechanics while explicit feedback degraded motor learning. Our results indicate that implicit feedback should be used in programs to lower the ACL injury risk. We suggest that implicit feedback should be frequent in the beginning and not be reduced as much following the acquisition phase.

Verbal augmented feedback in the rehabilitation of lower extremity musculoskeletal dysfunctions: a systematic review

Background

Verbal augmented feedback (VAF) is commonly used in physiotherapy rehabilitation of individuals with lower extremity musculoskeletal dysfunction or to induce motor learning for injury prevention. Its effectiveness for acquisition, retention and transfer of learning of new skills in this population is unknown.

Objectives

First, to investigate the effect of VAF for rehabilitation and prevention of lower extremity musculoskeletal dysfunction. Second, to determine its effect on motor learning and the stages of acquisition, retention and transfer in this population.

Design

Systematic review designed in accordance with the Centre for Reviews and Dissemination and reported in line with Preferred Reporting Items for Systematic Review and Meta-analysis.

Method

MEDLINE, Embase, PubMed and five additional databases were searched to identify primary studies with a focus on VAF for prevention and rehabilitation of lower extremity musculoskeletal dysfunction. One reviewer screened the titles and abstracts. Two reviewers retrieved full text articles for final inclusion. The first reviewer extracted data, whereas the second reviewer audited. Two reviewers independently assessed risk of bias and quality of evidence using Cochrane Collaboration’s tool and Grading of Recommendations Assessment, Development and Evaluation, respectively.

Results

Six studies were included, with a total sample of 304 participants. Participants included patients with lateral ankle sprain (n=76), postoperative ACL reconstruction (n=16) and healthy individuals in injury prevention (n=212). All six studies included acquisition, whereas retention was found in five studies. Only one study examined transfer of the achieved motor learning (n=36). VAF was found to be effective for improving lower extremity biomechanics and postural control with moderate evidence from five studies.

Conclusion

VAF should be considered in the rehabilitation of lower extremity musculoskeletal dysfunctions. However, it cannot be unequivocally confirmed that VAF is effective in this population, owing to study heterogeneity and a lack of high-quality evidence. Nevertheless, positive effects on lower extremity biomechanics and postural control have been identified. This suggests that further research into this topic is warranted where an investigation of long-term effects of interventions is required. All stages (acquisition, retention and transfer) should be evaluated.

Extrinsic visual feedback and additional cognitive/physical demands affect single-limb balance control in individuals with ankle instability

AIM

To investigate the impact of extrinsic visual feedback and additional cognitive/physical demands on single-limb balance in individuals with ankle instability.

METHODS

Sixteen subjects with ankle instability participated in the study. Ankle instability was identified using the Cumberland Ankle Instability Tool (CAIT). The subject’s unstable ankle was examined using the Athletic Single Leg Stability Test of the Biodex Balance System with 4 different protocols: (1) default setting with extrinsic visual feedback from the monitor; (2) no extrinsic visual feedback; (3) no extrinsic visual feedback with cognitive demands; and (4) no extrinsic visual feedback with physical demands. For the protocol with added cognitive demands, subjects were asked to continue subtracting 7 from a given number while performing the same test without extrinsic visual feedback. For the protocol with added physical demands, subjects were asked to pass and catch a basketball to and from the examiner while performing the same modified test.

RESULTS

The subject’s single-limb postural control varied significantly among different testing protocols (F = 103; P = 0.000). Subjects’ postural control was the worst with added physical demands and the best with the default condition with extrinsic visual feedback. Pairwise comparison shows subjects performed significantly worse in all modified protocols (P < 0.01 in all comparisons) compared to the default protocol. Results from all 4 protocols are significantly different from each other (P < 0.01) except for the comparison between the “no extrinsic visual feedback” and “no extrinsic visual feedback with cognitive demands” protocols. Comparing conditions without extrinsic visual feedback, adding a cognitive demand did not significantly compromise single-limb balance control but adding a physical demand did. Scores from the default protocol are significantly correlated with the results from all 3 modified protocols: No extrinsic visual feedback (r = 0.782; P = 0.000); no extrinsic visual feedback with cognitive demands (r = 0.569; P = 0.022); no extrinsic visual feedback with physical demands (r = 0.683; P = 0.004). However, the CAIT score is not significantly correlated with the single-limb balance control from any of the 4 protocols: Default with extrinsic visual feedback (r = -0.210; P = 0.434); no extrinsic visual feedback (r = -0.450; P = 0.081); no extrinsic visual feedback with cognitive demands (r = -0.406; P = 0.118); no extrinsic visual feedback with physical demands (r = -0.351; P = 0.182).

CONCLUSION

Single-limb balance control is worse without extrinsic visual feedback and/or with cognitive/physical demands. The balance test may not be a valid tool to examine ankle instability.

Treatment and prevention of acute and recurrent ankle sprain: an overview of systematic reviews with meta-analysis

BACKGROUND

Ankle sprains are highly prevalent with high risk of recurrence. Consequently, there are a significant number of research reports examining strategies for treating and preventing acute and recurrent sprains (otherwise known as chronic ankle instability (CAI)), with a coinciding proliferation of review articles summarising these reports.

OBJECTIVE

To provide a systematic overview of the systematic reviews evaluating treatment strategies for acute ankle sprain and CAI.

DESIGN

Overview of intervention systematic reviews.

PARTICIPANTS

Individuals with acute ankle sprain/CAI.

MAIN OUTCOME MEASUREMENTS

The primary outcomes were injury/reinjury incidence and function.

RESULTS

46 papers were included in this systematic review. The reviews had a mean score of 6.5/11 on the AMSTAR quality assessment tool. There was strong evidence for bracing and moderate evidence for neuromuscular training in preventing recurrence of an ankle sprain. For the combined outcomes of pain, swelling and function after an acute sprain, there was strong evidence for non-steroidal anti-inflammatory drugs and early mobilisation, with moderate evidence supporting exercise and manual therapy techniques. There was conflicting evidence regarding the efficacy of surgery and acupuncture for the treatment of acute ankle sprains. There was insufficient evidence to support the use of ultrasound in the treatment of acute ankle sprains.

CONCLUSIONS

For the treatment of acute ankle sprain, there is strong evidence for non-steroidal anti-inflammatory drugs and early mobilisation, with moderate evidence supporting exercise and manual therapy techniques, for pain, swelling and function. Exercise therapy and bracing are supported in the prevention of CAI.

Effects of external focus of attention on balance: a short review

[Purpose] The present study reviewed studies that examined the effects of attentional focus on balance. [Methods] Keywords such as “attentional”, “focus”, and “balance” were used to find relevant research papers in PubMed (www.ncbi.nlm.nih.gov/pubmed). Forty-five papers were found, and 18 of them were used for this study, excluding review papers and papers irrelevant to the topic of this study. [Results] Among the papers used for the review, the number of papers in which external focus produced effective outcomes was 15 (83.3%). The number of papers in which both external and internal focus produced effective outcomes was 2 (11.1%). The number of paper in which no instruction about attentional focus was effective was 1 (5.5%), and the number of papers in which internal focus was effective was zero. [Conclusion] This short review suggests clinical implications about how physical therapists can use attentional focus for balance rehabilitation of patients. Instructions about external focus of attention can generally be useful as a method to improve posture and balance control. Furthermore, the present reviews indicates that external focus of attention would be more useful in a rehabilitation stage in which the difficulty level of balance performance is gradually increased.

Optimization of the anterior cruciate ligament injury prevention paradigm: novel feedback techniques to enhance motor learning and reduce injury risk

Primary anterior cruciate ligament (ACL) injury prevention programs effectively reduce ACL injury risk in the short term. Despite these programs, ACL injury incidence is still high, making it imperative to continue to improve current prevention strategies. A potential limitation of current ACL injury prevention training may be a deficit in the transfer of conscious, optimal movement strategies rehearsed during training sessions to automatic movements required for athletic activities and unanticipated events on the field. Instructional strategies with an internal focus of attention have traditionally been utilized, but may not be optimal for the acquisition of the control of complex motor skills required for sports. Conversely, external-focus instructional strategies may enhance skill acquisition more efficiently and increase the transfer of improved motor skills to sports activities. The current article will present insights gained from the motor-learning domain that may enhance neuromuscular training programs via improved skill development and increased retention and transfer to sports activities, which may reduce ACL injury incidence in the long term.

The effects of attentional focus on jump performance and knee joint kinematics in patients after ACL reconstruction

OBJECTIVES

The purpose of this study was to determine the effect of an internal and external attentional focus on single leg hop jump distance and knee kinematics in patients after ACL reconstruction (ACLR).

DESIGN

Experimental.

SETTING

Outpatient physical therapy facility.

PARTICIPANTS

Sixteen patients after ACLR.

MAIN OUTCOME MEASURES

Patients received either an instruction with an internal focus or an external focus before performing a single leg hop jump. The jump distance, knee valgus angle at initial contact, peak knee valgus angle, knee flexion angle at initial contact, peak knee flexion angle, total ROM and time to peak angles for the injured and non-injured legs were recorded. A repeated measures MANOVA was used to determine significance between the experimental conditions with the primary outcome measures as dependent variables.

RESULTS

The external focus group had significant larger knee flexion angles at initial contact, peak knee flexion, total ROM and time to peak knee flexion for the injured legs.

CONCLUSIONS

This study demonstrates the applicability of using an external focus during rehabilitation of patients after ACLR to enhance safer movement patterns compared to an internal focus of attention and subsequently may help to reduce second ACL injury risk.

Feedback techniques to target functional deficits following anterior cruciate ligament reconstruction: implications for motor control and reduction of second injury risk

Primary anterior cruciate ligament (ACL) injury prevention training has been shown to reduce the risk of injury. Less is known about the effect of prevention on second injury after ACL reconstruction (ACLR). Given recent findings that second injury rates exceed 20 % in only the first year following the return to sport, it is imperative that rehabilitation after ACLR is scrutinized so that second injury preventative strategies can be optimized. A potential limitation of current rehabilitative processes following ACLR could be a deficiency in the transition from conscious awareness achieved during rehabilitation sessions to unexpected and automatic movements required for athletic activities on the field. Learning strategies with an internally directed focus have traditionally been utilized but may be less suitable for acquisition of control of complex motor skills required for sport reintegration. Conversely, an externally focused rehabilitation strategy may enhance skill acquisition more efficiently and increase the potential to transfer to competitive sport. This article presents new insights gained from the motor learning domain that may improve neuromuscular training programmes via increased retention from improved techniques and may ultimately reduce the incidence of second ACL injuries.

Novel methods of instruction in ACL injury prevention programs, a systematic review

Anterior cruciate ligament (ACL) injury prevention programs have been successful in the short term. Motor learning strategies with an internal focus (IF) to body movements have traditionally been utilized, but may be less suitable than an external focus (EF) for the acquisition and control of complex motor skills required for sport. To investigate the available literature and provide an overview of the effect of IF and EF instructions on jump landing technique. Systematic searches were conducted in PubMed (1966 to May 2014), CINAHL (1981 to May 2014) and PsycInfo (1989 to May 2014). A priori defined inclusion criteria were: (i) full text; (ii) published in English, German or Dutch; (iii) healthy adult subjects (mean age ≥18 years); (iv) jump and landing performance tested and (v) study used comparison between an EF and IF. Performance (jump height and distance) and technique (kinematics and kinetics) were the primary outcome variables of interest. Nine papers were included. Significant better motor performance and movement technique was found with an EF compared to an IF. Considering the beneficial results in the included studies when utilizing an EF, it is suggested to implement these strategies into ACL injury prevention programs.

Thinking about muscles: the neuromuscular effects of attentional focus on accuracy and fatigue

Although the effects of attention on movement execution are well documented behaviorally, much less research has been done on the neurophysiological changes that underlie attentional focus effects. This study presents two experiments exploring effects of attention during an isometric plantar-flexion task using surface electromyography (sEMG). Participants' attention was directed either externally (towards the force plate they were pushing against) or internally (towards their own leg, specifically the agonist muscle). Experiment 1 tested the effects of attention on accuracy and efficiency of force produced at three target forces (30, 60, and 100% of the maximum voluntary contraction; MVC). An internal focus of attention reduced the accuracy of force being produced and increased cocontraction of the antagonist muscle. Error on a given trial was positively correlated with the magnitude of cocontraction on that trial. Experiment 2 tested the effects of attention on muscular fatigue at 30, 60 and 100%MVC. An internal focus of attention led to less efficient intermuscular coordination, especially early in the contraction. These results suggest that an internal focus of attention disrupts efficient motor control in force production resulting in increased cocontraction, which potentially explains other neuromechanical findings (e.g. reduced functional variability with an internal focus).

The effect of balance confidence and context on functional reach ability in healthy older adults

OBJECTIVE

To assess functional reach (FR) ability in 4 contexts in older adults (≥ 60 years) with high balance confidence (HBC) and low balance confidence (LBC).

DESIGN

A repeated-measures design was used to compare 2 groups in 4 reaching contexts.

SETTING

Community setting.

SUBJECTS

Twenty-four healthy older adults with HBC and 27 healthy older adults with LBC.

METHODS

FR distance was assessed in 4 contexts presented in random order: (1) traditional FR (TFR); (2) functional reach on foam (FRF); (3) object present functional reach (OPFR); and (4) object present functional reach on foam (OPFRF). For TFR and FRF, 3 trials were performed for each task, and the average reach distance across 3 trials was calculated. During the OPFR and OPFRF contexts, the object was moved toward or away from the participant in 1.3-cm increments until maximal reach distance to the object was obtained.

MAIN OUTCOME MEASURE

Maximal reach distance in each of the 4 FR contexts.

RESULTS

Participants in the HBC group scored significantly higher than did participants in the LBC group regardless of reaching contexts (P =.004). For both balance confidence groups, reaching distance increased significantly from FRF to TFR to OPFRF to OPFR (P < .001).

CONCLUSION

The results of this study highlight the beneficial effect of an external target on balance performance, even with the added challenge of an unstable surface. These findings suggest that although balance performance is greater for persons with HBC, the same pattern of reaching ability in differing FR contexts is found regardless of whether balance confidence is high or low. The clinical utility of these findings pertain to the importance of the use of task objects during FR balance assessment to determine an individual's balance capacity. Future research is needed to assess the effectiveness of context-oriented reaching tasks in balance training programs.

Ankle sprain: pathophysiology, predisposing factors, and management strategies

With the high percentage (up to 75%) of initial lateral ankle sprains (LAS) leading to repetitive sprains and chronic symptoms, it is imperative to better understand how best to treat and rehabilitate LAS events. The purpose of this paper is to review LAS pathophysiology, predisposing factors, and the current evidence regarding therapeutic modalities and exercises used in the treatment of LAS. Functional rehabilitation, early mobilization with support, is the current standard of care for LAS. However, the high percentage of reinjury occurrence and development of chronic symptoms (up to 75%) after a LAS, suggests the current standard of care may not be effective. Recent evidence has shown the need for more stringent immobilization to facilitate ligament healing and restoration of joint stability and function after a LAS. Additionally, the importance of adding adjunctive therapies, specifically joint mobilizations and balance training have been shown to improve function and decrease the incidence of reinjury after a LAS. Modifying current rehabilitation protocols to include protecting the ankle joint with stringent immobilization, and including joint mobilizations and balance training may be the first step to decreasing the incidence of short and long term ankle joint dysfunction.

Bilateral balance impairments after lateral ankle trauma: a systematic review and meta-analysis

Research indicates that balance is impaired in the involved limb following an ankle injury. However, bilateral balance impairments are a viable reason for previous non-significant findings between involved and uninvolved limbs. The purpose of this investigation was to conduct a meta-analysis on studies reporting the effects of lateral ankle trauma on balance of the involved and uninvolved limb after acute ankle injury and chronic ankle instability. Twelve studies qualified for inclusion and assessed static balance for both the involved and uninvolved limbs post-injury and a control group. Meta-analyses calculated standardized mean difference effects and explored moderating variables for the involved and uninvolved limbs relative to controls. A significant cumulative effect size (ES=0.448, p<0.00001) indicated that balance of the involved limb is impaired after a history of ankle injury. Moderator variable analysis revealed that both acute (ES=0.529, p<0.0002) and chronic (ES=0.338, p<0.001) lateral ankle trauma negatively affected balance. Analysis of the uninvolved limb also revealed postural stability impairments (ES=0.275, p<0.003). Additional, moderator analysis showed a significant acute effect (ES=0.564, p<0.0001), but failed to find significance for individuals with chronic ankle instability (ES=0.070, p=0.552). These findings provide strong evidence that balance is bilaterally impaired after an acute lateral ankle sprain. However, these findings suggest that bilateral balance deficits are not present in patients with chronic ankle instability. Based on these findings, the uninvolved limb should not be used as a reference for "normal balance" following an acute lateral ankle sprain. Further, patients with acute lateral ankle sprains should undergo balance training on both limbs.

Attentional demands and postural control in athletes with and without functional ankle instability

STUDY DESIGN

Case-control study.

OBJECTIVE

To compare the effect of dual-tasking on postural and cognitive performance between subjects with functional ankle instability (FAI) and a matched control group without FAI.

BACKGROUND

Deficit and expertise in sensorimotor functions have been proposed as factors that can modify the interference between postural control and cognition. To the authors' knowledge, no study has investigated the posture-cognition interaction in individuals with recurrent ankle sprain, an orthopaedic condition with documented sensorimotor deficits.

METHODS

Single-limb postural stability was assessed in 15 recreational athletes with FAI and 15 matched healthy athletes without FAI. Each athlete stood on a Biodex Stability System at platform stabilities of 7 and 5, while they performed or did not perform a digits-backward cognitive task. Overall stability index (OSI), anteroposterior stability index (APSI), and mediolateral stability index (MLSI) were used as measures of postural performance.

RESULTS

At stability level 5, the individuals in the FAI group had poorer postural stability compared to those in the group without FAI (OSI, P<.01; MLSI, P<.01). A significant increase in OSI (P<.01) and MLSI (P = .02) was also demonstrated by the individuals in the FAI group during dual-task performance compared to the single-task performance.

CONCLUSION

Subjects with FAI demonstrated poorer postural stability when tested at level 5 on the Biodex Stability System, but not at level 7. Also, the results indicate that concurrent performance of a cognitive task decreased postural stability in the subjects with FAI, suggesting an increased dependency on attentional demands for maintenance of balance in that group. Such findings highlight the need for the assessment of postural control in patients with ankle sprain to include cognitive loading.

Influence of knee position on the postural stability index registered by the Biodex Stability System

The importance of knee position for bodily stability is described by some authors, however Biodex Stability System (BSS) trials have not been used to assess the reliability and effects of different knee positions. The purposes of this study were to test the reliability of BSS indices using two knee positions in the measurement protocol (either permitting slight knee flexion or maintaining them locked in total extension) and to compare the BSS indices between these two knee positions. The measurements were taken of the Overall Stability Index (OSI), Anterior-Posterior Stability Index (APSI) and Medial-Lateral Stability Index (MLSI) during a 30s protocol which gradually and automatically increased in difficulty among 21 healthy female subjects (22.8+/-1.0 years old). The subjects performed four trials which, without visual feedback, permitted knee flexion as well as four trials which did not, in a randomized order. The first two trials in each set were used for familiarization only. Permitting slight flexion yielded better reliability results (OSI Intra-class Correlation Coefficient [ICC]=0.93, APSI ICC=0.90, MLSI ICC=0.89) than maintaining the knee in total extension (OSI ICC=0.88, APSI ICC=0.87, MLSI ICC=0.79), with good agreement in the Bland and Altman test. Moreover, permitted knee flexion in BSS presented better balance stability values for OSI (P=0.001) and APSI (P=0.024), however the MLSI did not present significant difference between positions (P=0.345).