Balance measures for discriminating between functionally unstable and stable ankles

The Effects of Motor Imagery on Static and Dynamic Balance and on the Fear of Re-Injury in Professional Football Players with Grade II Ankle Sprains

Lateral ankle sprains are one of the most frequent athletic injuries in football, causing deficits in balance. Motor Imagery (MI) has been successively included in sports rehabilitation as a complementary therapeutic intervention. The aim of the present study was to explore the effects of MI on static and dynamic balance and on the fear of re-injury in professional football players with Grade II ankle sprains. Fifty-eight participants were randomly allocated into two groups: First-MI group (n = 29) and second-Placebo group (n = 29), and they each received six intervention sessions. The first MI group received MI guidance in addition to the balance training program, while the second Placebo group received only relaxation guidance. One-way ANOVA showed statistically significant results for all variables, both before and 4 weeks after the interventions for both groups. The t-test showed statistically significant differences between the two groups for static balance for the right lower extremity (t = 3.25, S (two-tailed) = 0.002, p < 0.05) and also for heart rate (final value) in all time phases. Further research is needed in order to establish MI interventions in sports trauma recovery using stronger MI treatments in combination with psychophysiological factors associated with sports rehabilitation.

Normative Standards for Isokinetic and Anthropometric Classifications of University-Level Netball Players

CONTEXT

The purpose of the study was to develop normative ranges and standards for knee and shoulder isokinetic and anthropometric values. These standards can be qualitatively interpreted and allow practitioners to classify isokinetic and anthropometric values more objectively for university-level netball players.

DESIGN

Posttest only observational study design. All players were only evaluated once during the in-season to generate normative ranges.

METHODS

A total of 51 female players volunteered. Participants were evaluated on an isokinetic dynamometer at 60° per second to obtain knee-extensor and knee-flexor values as well as shoulder-flexor and shoulder-extensor values. A total of 16 anthropometric variables were collected including stature, body mass, 8 skinfolds, and 6 circumferences. Between-group differences were calculated to determine whether playing level was a differentiating factor in data.

RESULTS

Normative standards were developed for isokinetic parameters associated with the knee and shoulder joints as well as skinfolds and circumference measures. No statistically significant between-group differences were evident (χ2Kruskal-Wallis[2] = 3.96, P = .140).

CONCLUSION

These standards can be used by coaches and practitioners to set attainable goals for individual players or those from secondary leagues, classify individual and team-based performances, and facilitate decision-making processes.

Accuracy to identify young adults with chronic ankle instability using a virtual reality - Balance error scoring system: A cross-sectional study

INTRODUCTION

The Balance Error Scoring System (BESS) assesses the ability to control postural stability by performing 3 different stances on two-type surfaces during closed eyes. Virtual reality technology combined with the BESS test (VR-BESS) may be used to disrupt visual inputs instead of closing the eyes, which may improve the sensitivity of diagnosing patients with chronic ankle instability (CAI).

OBJECTIVE

This study aimed to evaluate the accuracy to identify individuals with CAI of the VR-BESS test comparing with the original BESS test.

METHODS

The BESS and VR-BESS tests were administered to 68 young adults (34 participants with CAI and 34 without CAI). Frontal and lateral video views were used to measure the participant's performance errors. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve was computed to determine the diagnostic test's overall accuracy.

RESULTS

The total score of the BESS test and the VR-BESS test were statistically significant in comparison to the AUC of no discrimination at 0.5, with AUC values of 0.63 and 0.64, respectively. The cut-off scores for the BESS and VR-BESS tests were 12 and 15, respectively. There was no significant difference between the ROC curves of the BESS and the VR-BESS test for identifying individuals with CAI.

CONCLUSION

The BESS and VR-BESS tests may be utilized interchangeably to identify individuals with CAI.

Deficits in proprioception and strength may contribute to the impaired postural stability among individuals with functional ankle instability

Purpose: The correlations of postural stability with proprioception and strength may explain the recurrent sprains among individuals with functional ankle instability (FAI). This study aimed to compare anterior-posterior (AP) and medial-lateral (ML) postural stability, along with ankle proprioception and strength between individuals with and without FAI and investigated their correlations. Methods: Forty participants with FAI and another 40 without FAI were recruited. Their postural stability, represented by time to stabilization (TTS) in the AP (TTSAP) and ML (TTSML) directions, was calculated by the ground reaction force during jumping onto a force plate. Their ankle proprioception and strength during plantarflexion/dorsiflexion and inversion/eversion were measured using a proprioception device and a strength testing system, separately. Results: Individuals with FAI had longer TTSAP (p = 0.015) and TTSML (p = 0.006), larger ankle proprioception thresholds (p = 0.000-0.001), and less strength (p = 0.001-0.017) than those without FAI. Correlations between strength and TTSAP were detected among individuals with (ankle plantarflexion, r = -0.409, p = 0.009) and without FAI (ankle plantarflexion, r = -0.348, p = 0.028; ankle dorsiflexion, r = -0.473, p = 0.002). Correlations of proprioception (ankle inversion, r = 0.327, p = 0.040; ankle eversion, r = 0.354, p = 0.025) and strength (ankle eversion, r = -0.479, p = 0.002) with TTSML were detected among individuals without FAI but not among those with FAI. Conclusion: Individuals with FAI have worse postural stability and proprioception and less strength. Their proprioception and strength decreased to a point where they could not provide sufficient functional assistance to the ML postural stability. Improvements in proprioception and strength may be keys to prevent recurrent ankle sprains among individuals with FAI.

Postural Control Deficits During Static Single-leg Stance in Chronic Ankle Instability: A Systematic Review and Meta-Analysis

CONTEXT

Postural control deficits arising from injured ankles are central to chronic ankle instability (CAI) and its persistent symptoms. This is usually measured by recording the center of pressure (CoP) trajectory during static single-leg stance using a stable force plate. However, existing studies have produced conflicting results on whether this mode of measurement adequately reveals the postural deficits in CAI.

OBJECTIVE

To determine whether postural control during static single-leg stance is impaired in CAI patients when compared with uninjured healthy controls.

DATA SOURCES

Literature databases, PubMed, Embase, Web of Science, Cochrane Library, Scopus, CINAHL, and SPORTDiscus, were searched from inception to April 1, 2022, using ankle-, injury-, and posture-related terms.

STUDY SELECTION

Two authors independently performed the step-by-step screening of article titles, abstracts, and full texts to select peer-reviewed studies investigating CoP trajectory during static single-leg stance using a stable force plate in CAI patients and healthy controls. A total of 13,637 studies were reviewed, and 38 studies (0.003%) met the selection criteria.

STUDY DESIGN

Meta-analyses of descriptive epidemiological study.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

CoP parameters, sway directions, visual condition, and numerical data (means and standard deviations) were extracted.

RESULTS

The injured ankles of CAI patients had higher standard deviations of sway amplitude in both anterior-posterior and medial-lateral directions (standardized mean difference [SMD] = 0.36 and 0.31, respectively) under conditions of open eyes than controls. Higher mean sway velocity in anterior-posterior, medial-lateral, and total directions (SMD = 0.41, 0.37, and 0.45, respectively) with closed eyes was also found.

CONCLUSION

CAI patients had deficits of postural control during static single-leg stance, and these deficits were identified by the CoP trajectory. Further methodological explorations of CoP parameters and corresponding test conditions are required to enhance the sensitivity and reliability of postural deficit assessments in CAI using force plates.

Influence of quality of reduction using radiological criteria on kinematics and kinetics in ankle fractures with unstable syndesmotic injury

BACKGROUND

In ankle fractures with syndesmotic injury, the anatomic reduction of the ankle mortise is crucial for preventing osteoarthritis. Yet, no studies have analysed the effect of surgical reduction after unstable ankle fractures on patients' active functional outcome.

METHODS

The Intraoperative 3D imaging data of patients surgically treated between 2012 and 2019 for ankle fracture with concomitant syndesmotic injury were reviewed. 58 patients were allocated to two groups depending on whether the criteria for radiologically optimal reduction were met (39 patients) or not (19 patients). Criteria for optimal reduction were composed of objectively measured and subjectively rated data. After undertaking the Olerud/Molander ankle score, a gait analysis and several active function tests using 3D motion capture were performed in order to evaluate kinetic and kinematic differences between both groups.

FINDINGS

Patients showed deficits of range of motion and balance parameters on the injured ankle, however, there were no significant differences between both groups.

INTERPRETATION

Although, the data did not show that radiological reduction criteria have a statistically significant effect on active functional outcome after a mean follow up time of 5.7 years, tendencies for a better outcome of patients that met the criteria could be seen. It also must be taken into consideration that results are limited by case number and allocation ratio, which made a sub-analysis of the separate reduction criteria unfeasible.

Effects of Attrition Shoes on Balance Control Ability and Postural Stability Following a Single-Leg Drop Jump Landing

The purpose of the study is to determine the influence of lateral-heel-worn shoes (LHWS) on balance control ability through the single-leg drop jump test. The results could be beneficial by preventing lower limb injuries. Eighteen healthy participants performed the single-leg drop jump test. Times to stabilization for ground reaction forces (TTSG) in the anterior/posterior, medial/lateral, and vertical directions were calculated to quantify dynamic balance control ability. Outcome variables of the center of pressure (COP) were used to examine the main effect of LHWS during the static phase. The postural control ability was assessed through time to stabilization for the center of mass (TTSC) in the three directions. TTSG and TTSC for the LHWS group were found to be longer than those for the new shoes (NS) group in the M/L direction (p < 0.05). An increase in the TTS revealed an increased risk of falls during physical activities. However, no significant effects for both TTSG and TTSC were found in the other two directions between LHWS and NS groups. A static phase was cropped using TTSG for each trial, which indicated a phase after participants obtained balance. Outcome measures derived from COP showed no significant effects in the static phase. In conclusion, LHWS weakened balance control ability and postural stability in the M/L direction when compared to the NS group. During the static phase, no significant differences were found between the LHWS group and the NS group in balance control ability and postural stability. Consequently, lateral-worn shoes might increase the risk of fall injuries. The results could serve as an evaluation of shoe degradation for individuals with the aim of avoiding the risk of falls.

Comparison of balance and function in the long term after all arthroscopic ATFL repair surgery

INTRODUCTION

We compared the balance, ROM, clinical scores, kinesiophobia and functional outcomes of patients after all-arthroscopic ATFL repair surgery with the non-operated side and healthy control group.

MATERIALS AND METHODS

Twenty-five patients with follow up time 37.32 ± 12.51 months and twenty-five healthy controls participated in the study. Postural stability was evaluated with the Biodex® balance system by measuring overall (OSI), anterior-posterior (API), and mediolateral (MLI) stability index. Dynamic balance and function were measured using the Y-balance test (YBT) and single-leg hop test (SLH). Limb symmetry index for SLH and contralateral comparisons (YBT, OSI, API, MLI) was performed. The AOFAS score and the Tampa Scale of Kinesiophobia (TSK) were applied. Two subgroups were created (with OLT and without OLT).

RESULTS

There was no statistically significant difference between subgroups. There was no statistically significant difference between bilateral OSI, API, MLI values and YBT anterior reach distances of all groups. Single leg OSI (0.78 ± 0.27/0.55 ± 0.12), API (0.55 ± 0.22/0.41 ± 0.10), and MLI (0.40 ± 0.16/ 0.26 ± 0.08) values were significantly worse and YBT posteromedial (73.88 ± 15.70/89.62 ± 12.25), posterolateral reach (78.03 ± 14.08/92.62 ± 8.25) and the SLH distance (117.14 ± 27.84/165.90 ± 20.91) were significantly lower on the patients than controls (p < 0.05), respectively. In contralateral comparisons, all reach distances on YBT were similar and SLH limb symmetry index of the operated side was 98.25%. AOFAS scores of the patients were 92.62 ± 11.13, TSK scores were 46.45 ± 11.32, and 21 patients (84%) had kinesiophobia.

CONCLUSION

AOFAS score, limb symmetry index, and bilateral balance of the patients were successful; however, there is single-leg postural stability insufficiency and kinesiophobia. Although the extremity symmetry index of the operated side of the patients was 98.25, the fact that these values are lower than those of the healthy control may have been caused by kinesiophobia. During the long-term rehabilitation, kinesiophobia should be considered and single-leg balance exercises should be monitored during the rehabilitation period.

LEVEL OF EVIDENCE

Level III.

Validity and Reliability of Kinvent Plates for Assessing Single Leg Static and Dynamic Balance in the Field

The objective of this study was to validate PLATES for assessing unipodal balance in the field, for example, to monitor ankle instabilities in athletes or patients. PLATES is a pair of lightweight, connected force platforms that measure only vertical forces. In 14 healthy women, we measured ground reaction forces during Single Leg Balance and Single Leg Landing tests, first under laboratory conditions (with PLATES and with a 6-DOF reference force platform), then during a second test session in the field (with PLATES). We found that for these simple unipodal balance tests, PLATES was reliable in the laboratory and in the field: PLATES gives results comparable with those of a reference force platform with 6-DOF for the key variables in the tests (i.e., Mean Velocity of the Center of Pressure and Time to Stabilization). We conclude that health professionals, physical trainers, and researchers can use PLATES to conduct Single Leg Balance and Single Leg Landing tests in the laboratory and in the field.

Effects of Plantar Flexor Stretching on Static and Dynamic Balance in Healthy Adults

Stretching can affect balance ability by generating biomechanical and physiological changes in the postural muscles. Stretching of the lower extremity muscles can greatly affect posture maintenance strategies and balance ability. However, the relationship between stretching and balance ability has not been clarified. Therefore, this study aimed to investigate the effect of plantar flexor stretching on balance ability. Forty-four healthy young adults were randomly assigned to four groups (static stretching, dynamic stretching, ballistic stretching, and control). Ankle joint range of motion, static balance ability, and dynamic balance ability were evaluated before, immediately after, and 20 min after stretching. Stretching did not affect balance ability in the open-eye condition. After stretching, the sway area was significantly reduced in the closed-eye condition (p < 0.05). After stretching, the reach distance of dynamic balance ability increased significantly (p < 0.05). The results show that plantar flexor stretching can positively affect balance ability. Therefore, plantar flexor stretching should be considered a rehabilitation method to improve balance.

Effects of fatigue on balance and ankle proprioception during drop landing among individuals with and without chronic ankle instability

This study aimed to explore the effects of fatigue on the balance and ankle proprioception during drop landing of individuals with chronic ankle instability (CAI). A total of 35 participants with unilateral CAI and 35 healthy participants participated in this study. A static balance test, dynamic balance test, and ankle proprioception test were conducted before and after fatigue. Fatigue was induced with turn back runs and vertical jumps protocol. Sway distance of the center of pressure (COP), root mean square of the COP (RMS), total excursions (TOTEX), mean velocity (MVELO), 95% confidence ellipse area of the COP movements (95% AREA), Normalise Reach Distance in the anterior (ANT), posteromedial (PM), and posterolateral (PL) directions, and the area under the curve (AUC) were calculated and analyzed. There were significant group by fatigue interactions for static balance variables, normalise reach distance in the PM and PL directions, and AUC. Fatigue reduced balance and ankle proprioception in individuals with CAI. After fatigue, static and dynamic balance and ankle proprioception during drop landing were significantly worse in the CAI group than in the control group. Fatigue had a significant negative effect on balance and ankle proprioception in CAI patients. Therefore, fatigue may be an important factor causing repeated ankle sprain in CAI patients.

The influence of local pain on balance control in patients with chronic ankle instability

Background

Local pain around the ankle joint is a common symptom in patients with chronic ankle instability (CAI). However, whether the local pain would impose any influence on the balance control performance of CAI patients is still unknown.

Methods

A total of twenty-six subjects were recruited and divided into the following two groups: pain-free CAI (group A) and pain-present CAI (group B). Subjects in both groups received two independent tests: the star excursion balance test and the single-leg stance test, in order to reflect their balance control ability more accurately.

Results

Compared with group A, the group B showed significantly more episodes of the history of sprains, decreased ankle maximum plantarflexion angle, and lower Cumberland scores (all p < 0.05). In the star excursion balance test, group B demonstrated a significantly reduced anterior reach distance than group A (p < 0.05). During the single leg stance test, group B showed a significant increase in the magnitude of electromyographic signals both in peroneus longus and soleus muscles than group A (each p < 0.05). Additionally, group B had a significantly more anterolaterally positioned plantar center of pressure than group A (p < 0.05).

Conclusion

CAI patients with local pain around the ankle joint had more episodes of sprains and lower functional scores when compared to those without pain. The balance control performance was also worse in the pain-present CAI patients than those without pain.

Effects of 12 weeks of Tai Chi Chuan intervention on the postural stability and self-reported instability in subjects with functional ankle instability: Study protocol for a randomized controlled trial

Background

Tai Chi Chuan (TCC) is a physical activity modality that originated in China and is now widely popular around the world. Although there are a series of articles reporting that TCC can improve balance and other functional symptoms in a variety of populations, including the elderly, patients with stroke, and patients with Parkinson's disease, its efficiency has not been scientifically and methodically evaluated in subjects with functional ankle instability (FAI). Moreover, there is no literature directly comparing TCC and conventional balance training (CBT) interventions for FAI. The objective of this study is to investigate the comparative effects of TCC intervention and CBT protocols in improving postural balance and subjective instability feelings in patients with FAI.

Methods

This study will be a single-center, parallel group, randomized controlled trial. Sixty-eight patients with FAI will be included and randomly assigned in a 1:1 ratio to either an intervention group (n =34) or a control group (n = 34). The participants in the intervention group will complete 12 weeks of TCC intervention (40 min/time, 3 times/week for 12 weeks) on the basis of health education treatment. The control group will receive health education and 36 CBT sessions during a 12-week period. Outcome measures include postural stability and self-reported feelings of instability at baseline, after the end of the intervention, and 3-month follow-up. The postural stability assessment of patients with FAI will be detected by performing static and dynamic postural tests, which will be carried out through a specific balance platform (TecnoBody ProKin). Self-reported feelings of instability will be assessed by Cumberland Ankle Instability Tool (CAIT), American Orthopedics Foot and Ankle Society's Ankle–Hindfoot Evaluation Scale (AOFAS-AHES), and the MOS item Short Form Health Survey (SF-36).

Discussion

This trial will demonstrate whether a 12-week TCC intervention positively affects postural stability and self-reported outcomes in patients with FAI. At the same time, the superiority of its clinical efficacy will also be compared with that of CBT. This study may also help to redefine the value of traditional Chinese exercises in the treatment of chronic ankle instability.

Clinical trial registration

Chinese Clinical Trial Registry: ChiCTR2100041790. Registration date: 22 March 2021. http://www.chictr.org.cn/edit.aspx?pid=119501&htm=4.

Can stabilization analysis following a single leg drop jump be compared between young and middle-aged adults

We aimed to verify whether the computational approaches previously proposed to analyze stability after a single-leg drop-jump (SLDJ) could be applied to a population of middle-aged adults. Fifteen middle-aged (56.4 ± 4.6 years) and 15 young adults (26.7 ± 3.9 years) performed five SLDJs. Stabilization measurements included (1) time to stabilization (TTS) based on vertical ground reaction force (GRF) (TTSv) and a fixed stabilization threshold; (2) TTS based on medio-lateral GRF (TTSml) using five different methods to preprocess the signal and stabilization threshold; (3) early medio-lateral stabilization- the averaged absolute values of the GRF in 0.2-1.4 s post-landing; (4) late medio-lateral stabilization - the averaged absolute values of the GRF at 1 s-5 s after landing. TTSv showed longer TTS values in middle-aged participants. In addition, middle-aged adults showed greater sway in late stabilization. However, TTSml values varied considerably between calculation methods, and early stabilization showed no significant differences between groups except in the first 0.2 s after landing. The results of the current study suggest that TTS calculations are sensitive to signal and threshold selection, and to the processing method. Calculations based on a fixed threshold are more appropriate for studying dynamic postural stability in middle age. With appropriate method selection, a decreased stabilizing performance can be demonstrated in middle-aged adults compared to young adults.

Validity and reliability of smartphone-based application for chronic ankle instability

Background/aims

Ankle instability is one of the most common injuries that can occur during everyday life, sports and exercise. Recently, smartphone accelerometers have been used to measure single leg balance associated with ankle instability, because they are easy to use, inexpensive and can be used in small spaces. Thus, the purpose of this study was to introduce and investigate the intra- and inter-rater reliability of the smartphone accelerometer when assessing ankle instability.

Methods

A total of 26 individuals who had ankle instability were recruited. The single leg stance balance was measured using a smartphone accelerometer (Accelerometer application) and a force platform (I-Balance) for 5 seconds with their eyes open or their eyes closed.

Results

In the eyes open position, intra-rater reliability of the smartphone accelerometer was excellent for both raters (intraclass correlation coefficient: 0.87–0.90); and the inter-rater reliability was moderate (intraclass correlation coefficient: 0.71). In the eyes closed position, the intra-rater reliability of the smartphone accelerometer was excellent for both raters (intraclass correlation coefficient: 0.90–0.93); the inter-rater reliability was good (intraclass correlation coefficient: 0.82). Additionally, there were fair positive correlations between the smartphone accelerometer and the Cumberland Ankle Instability Tool, and between the smartphone accelerometer and I-Balance (r=0.33, 0.30 respectively).

Conclusions

The present study demonstrated excellent intra-rater reliabilities of two raters and moderate to good inter-rater reliabilities. The smartphone accelerometer offers several important advantages as a potential portable medical device to assess ankle instability accurately. Although there was a positive correlation, the relationships between the smartphone accelerometer and Cumberland Ankle Instability Tool and that between the smartphone accelerometer and I-Balance were fair. Future studies should investigate the validity of the smartphone accelerometer as a portable medical device for determining ankle instability.

The effects of visual feedback disruption on postural control with chronic ankle instability

OBJECTIVES

The purpose of this study was to identify the effects of reduced visual feedback via stroboscopic glasses on dynamic postural control among chronic ankle instability (CAI), lateral ankle sprain (LAS) coper and uninjured control participants.

DESIGN

Controlled trial in a laboratory setting.

METHODS

Twenty CAI patients, 20 copers, and 20 controls participated in this study. Each participant performed a single-leg hop stabilization test with eyes open (EO) and stroboscopic vision (SV). Two-way ANOVAs (group × condition) were used to examine the differences between group (CAI, coper, and control) and condition (EO and SV).

RESULTS

There was a significant group by condition interaction for DPSI scores. CAI patients displayed increased DPSI scores with SV compared to EO (p < 0.01), and CAI patients had increased DPSI scores only with SV when compared with controls. All participants displayed decreased dynamic postural control under the SV condition compared to the EO condition (p < 0.01) regardless of ankle group.

CONCLUSIONS

CAI patients rely more on visual feedback during dynamic postural control than copers and controls. However, they may not be as able to compensate for the disrupted visual feedback during a dynamic task. Regardless of ankle injury history, stroboscopic glasses could be cost-effective visual disruption devices during a dynamic balance task.

Altered Dynamic Postural Stability and Joint Position Sense Following British Army Foot-Drill

Impaired proprioceptive acuity negatively affects both joint position sense and postural control and is a risk factor for lower-extremity musculoskeletal injury in athletes and military personnel. British Army foot-drill is an occupational military activity involving cyclical high impact loading forces greater than those observed in athletes during high level plyometrics. Foot-drill may contribute to the high rates of lower-extremity overuse injuries observed in recruits during basic training. There is limited research investigating foot-drill specific injury risk factors in women, despite greater incidences of musculoskeletal injury reported in women (522 vs. 417 per 1,000 personnel, OR: 1.53) when compared to men during basic training. This study aimed to quantify changes in ankle joint proprioception and dynamic postural stability following a period of British Army foot-drill. Fourteen women of similar age to British Army female recruits underwent pre-post foot-drill measures of frontal plane ankle joint position sense (JPS) and dynamic postural stability using the dynamic postural stability index (DPSI). Passive ankle JPS was assessed from relative test angles of inversion 30% (IN30%) and eversion 30% (EV30%) and IN60% of participants range of motion using an isokinetic dynamometer. The DPSI and the individual stability indices (medio-lateral [MLSI], anterior-posterior [APSI], and vertical [VSI]) were calculated from lateral and forward jump-landing conditions using force plates. Foot-drill was conducted by a serving British Army drill instructor. Significantly greater absolute mean JPS error for IN30% and EV30% was observed post foot-drill (p ≤ 0.016, d ≥ 0.70). For both the lateral and forward jump-landing conditions, significantly greater stability index scores were observed for MLSI, APSI, and DPSI (p ≤ 0.017, d ≥ 0.52). Significantly greater JPS error and stability index scores are associated with the demands of British Army foot-drill. These results provide evidence that foot-drill negatively affects lower-extremity proprioceptive acuity in recruit age-matched women, which has implications for increased injury risk during subsequent military physical activity, occurring in a normal training cycle.

Effect of Novel Remodeled Bicycle Pedal Training on Balance Performance in Athletes With Functional Ankle Instability

Context

Appropriate training without risk of injury is a critical concern for athletes. Remodeled bicycle pedal training with multi-directional challenges may be effective in improving the balance performance of athletes with functional ankle instability (FAI).

Objective

To evaluate the effects of 6-week modified bicycle pedal training on the balance ability and proprioception of athletes with FAI.

Design

Randomized controlled trial.

Setting

University motion analysis laboratory.

Participants

Fourteen healthy athletes (healthy group) and twenty-six athletes with FAI and an age of 18 to 30 years old. The participants with FAI were randomly distributed to two groups, designated as the training group (AI-T group) and non-training group (AI-NT group), respectively. The athletes in the AI-T group received 6-week remodeled bicycle pedal training, while those in the AI-NT group received no intervention at all.

Intervention

A 6-week training using modified bicycle pedal capable of moving freely during loading cycle vs no intervention.

Main Outcome Measures

The passive ankle joint position sense (JPS) in four angles and the center of pressure (COP) parameters were analyzed during single-leg standing with and without vision, respectively.

Results

A 6-week remodeled pedal training: (1) significantly improved the passive JPS of ankle in all directions (P < 0.05); (2) reduced the excursion of the COP in the medial-lateral (ML) direction (p < 0.05), the velocity of the COP in the ML direction (p < 0.05), and the RMS of the COP in the ML direction (P < 0.05) during single-leg standing both with and without vision.

Conclusion

The remodeled bicycle pedal training improved the passive JPS and reduced the postural sway in single-leg standing both with and without vision. Therefore, remodeled bicycle pedal training can be considered for inclusion in rehabilitation programs for athletes with FAI to restore the proprioception and balance ability.

Single leg hopping in children with fetal alcohol spectrum disorder: Dynamic postural stability and kinematics

BACKGROUND

This study compared dynamic postural stability (DPS) and lower limb kinematics during single leg hopping (SLH) performed by typically-developed children from urban and rural settings and children with Fetal Alcohol Spectrum Disorder (FASD) from a rural setting.

METHODS

Typically-developed nine-year-old children from an urban (n = 27) and rural setting (n = 14) (controls), and nine-year-old children with FASD from a rural setting (n = 14) (cases) performed SLH and landing on a pressure mat. Motion analysis systems described 1) Spatiotemporal and centre of pressure parameters (COP) and lower limb sagittal plane kinematics. Descriptive results are presented in median and ranges and differences between groups were determined by Kruskal-Wallis and Mann-Whitney U statistical tests. The level of significance was p < 0.05.

RESULTS

During hopping, the urban controls had longer stance and swing times (p < 0.001) than the rural groups. The urban controls remained in greater hip flexion compared to the case group (p = 0.02). The urban controls landed in more plantarflexion at initial foot contact (IFC) than the cases (p < 0.001) and the rural controls (p = 0.03). The rural groups landed with greater knee extension at IFC than the urban controls (cases p = 0.04; rural controls p < 0.001). During the landing motion, the urban controls moved into more hip flexion compared to the cases (p = 0.015) and the rural controls (p = 0.026). The cases displayed greater COP anteroposterior values during landing compared to both control groups, but the case group displayed the fastest time to stability.

CONCLUSION

The different hopping strategies observed provides an indication of the movement capabilities of these groups.

Identification of Ankle Injury Risk Factors in Professional Soccer Players Through a Preseason Functional Assessment

Background

Etiologically, the risk of an ankle injury depends on extrinsic and intrinsic factors, such as muscle strength asymmetry, decreased flexibility, and decreased proprioception, as well as patient age and history of injuries.

Purpose/Hypothesis

The purpose of this study was to identify risk factors present in the preseason assessment that may predispose professional soccer players to ankle injuries. We hypothesized that analysis of these parameters could relate the incidence of injuries to the deficits found during the preseason period, enabling the identification of risk factors to predict the occurrence of injuries.

Study Design

Cohort study; Level of evidence, 2.

Methods

A total of 89 professional soccer athletes were evaluated in the preseason period; the evaluation included athlete history and anthropometric data collection, an isokinetic ankle evaluation, and functional tests: the Dorsiflexion Lunge Test and Y-Balance Test (YBT). The athletes were monitored during the competitive period, and the incidence of injuries was surveyed. The association of quantitative variables and injury outcomes was analyzed using the Student t test for independent samples, with P < .05. For the association of categorical variables and injury outcomes, the chi-square test was performed, with P < .05.

Results

A higher incidence of ankle injuries was associated with lower YBT scores in the dominant (P = .04) and nondominant (P = .01) limbs. A higher body mass index was also associated with a higher injury occurrence (P = .01).

Conclusion

Functional tests, such as the YBT, are indicated tools for assessing the physical capacities and possible risks of ankle sprains, as they can evaluate the ankle functional capacity in a complex way, identifying athletes more prone to ankle injuries. Athletes' body mass index should also be taken into account to prevent such injuries.

Comparison of Static and Dynamic Balance in Male Football and Basketball Players

Introduction. The aim of the present study was to compare static and dynamic balance among professional athletes in football and basketball. Methods. In this cross-sectional study, 47 professional, male football and basketball players from Pro League in Iran participated. They were divided into 3 groups. Group 1 included 16 participants with history of grade 1 or 2 single ankle sprain within the past 6 months. Group 2 included 17 participants with recurrent ankle sprain. Group 3 included 14 participants without history of ankle sprain. Static and dynamic balance were measured by the Balance Error Scoring System (BESS) and modified Star Excursion Balance Test (SEBT), respectively. Results. For the single-leg stance on a firm surface, group 2 scored errors with a high mean value of 3.94 compared with the other 2 groups, and the difference was statistically significant (P = .03). Significant differences in BESS scores are observed on both surfaces across the tandem limb between groups 2 and 3. Conclusion. The measures from the SEBTs may not reflect the balance performance especially in well-trained athletes who have a better balance when performing sport-related skills. However, BESS includes static postures, and it may reflect postural deficits better than dynamic tests in the more experienced athlete. Level of Evidence: Diagnostic, Level IV.

Individuals with recurrent ankle sprain demonstrate postural instability and neuromuscular control deficits in unaffected side

PURPOSE

To compare proprioception, postural stability, and neuromuscular control between patients with mechanical laxity and recurrent ankle sprain.

METHODS

Among 86 patients with ankle instability, 45 patients had mechanical laxity (mean age 27.2 ± 7.0 years) and 41 had recurrent ankle sprain (mean age 25.1 ± 9.2 years). Both the affected and unaffected ankles of each patient were evaluated. Proprioception and neuromuscular control tests were conducted using an isokinetic machine, and postural stability was tested using a postural stabilometry system.

RESULTS

Proprioception was not significantly different between the unaffected or affected ankles of the mechanical laxity group compared with those of the recurrent ankle sprain group (n.s). Static and dynamic postural stability and neuromuscular control were similar in the affected ankles between the two groups (n.s). However, postural stability (static, overall: p = 0.009, anterior-posterior: p = 0.028, medial-lateral: p = 0.022; dynamic, overall: p = 0.012, anterior-posterior: p = 0.004, medial-lateral: p = 0.001) and neuromuscular control (inversion: p = 0.031, eversion: p = 0.039, dorsiflexion: p = 0.029, plantarflexion: p = 0.035) were significantly decreased in the unaffected ankles of the recurrent ankle sprain group compared with those of the mechanical laxity group.

CONCLUSION

The unaffected ankles of the recurrent ankle sprain group showed significant decreases in both postural stability and neuromuscular control compared with the mechanical laxity group. Clinicians and therapists should consider unaffected ankle rehabilitation in patients with recurrent ankle sprain to prevent future sprain events.

LEVEL OF EVIDENCE

Case-control study, III.

The assessment of single-leg drop jump landing performance by means of ground reaction forces: A methodological study

BACKGROUND

Time to stabilization (TTS) and dynamic postural stability index (DPSI) are outcome measures based on ground reaction force (GRF) that are often used to quantify dynamic postural stability performance following a drop jump landing. However, their interrelations, as well as the overlap with other dynamic measures and static single-leg postural sway, are unknown.

RESEARCH QUESTION

What is the relation among TTS and DPSI, how are they related to impact forces and dynamic postural sway, and how are all these dynamic measures related to static postural sway?

METHODS

A sample of 190 elite soccer players performed four single-leg drop jump landings. TTS in three directions (vertical, anteroposterior, and mediolateral), and DPSI were intercorrelated (Pearson's r), and related to impact forces and the magnitude of horizontal GRF (HGRF) from 0.4 to 2.4 s and 3.0-5.0 s following landing. All these measures were also correlated to HGRF in the static phase (i.e., 5.3-11.7 s).

RESULTS

The TTS measures were significantly interrelated (r = 0.28-0.53), but were not significantly correlated to DPSI. TTS was more strongly related to HGRF0.4-2.4 s (r = 0.54-0.75) than to HGRF3.0-5.0 s (r = 0.32-0.54) or impact forces (r=-0.28-0.36). Vertical TTS was not significantly related to impact forces. The DPSI was most strongly related to the vertical peak force (r = 0.85), and was not significantly related to HGRF of the dynamic periods. Furthermore, TTS and dynamic HGRF were significantly related to static HGRF (r = 0.34-0.80), while DPSI and impact forces were not.

SIGNIFICANCE

TTS and DPSI do not represent similar aspects of single-leg jump landing performance. The ability to stabilize posture seems to be represented by TTS and dynamic postural sway, which partly overlaps with static postural sway. In contrast, DPSI and vertical peak force mainly reflect the kinetic energy absorption during impact. The findings can help to better understand the meaning of the outcome measures, and to translate results to rehabilitation or prevention programs.

Effect of Single-Leg Squat Speed and Depth on Dynamic Postural Control Under Single-Task and Dual-Task Paradigms

Although single-leg squats are a common dynamic balance clinical assessment, little is known about the relationship between parameters that influence squat movement and postural control performance. The objective of this study was to determine the relationships between squat parameters (speed and depth) and postural control under single task and dual task. A total of 30 healthy college students performed single-leg squats under single task and dual task with Stroop. Random-intercepts generalized linear mixed models determined the effect of squat parameters on center of pressure (CoP) parameters. For each 1-cm·s^-1 increase in squat speed, sway range (mediolateral: β = -0.03; anteroposterior: β = -0.05) and area (β = -0.25) decreased, whereas sway speed (mediolateral: β = 0.05; anteroposterior: β = 0.29; total: β = 0.29) increased. For each 1-cm increase in squat depth, sway range (mediolateral: β = 0.05; anteroposterior: β = 0.20) and area (β = 0.72) increased, whereas sway speed (anteroposterior: β = -0.14; total: β = -0.14) decreased. Compared with single task, the association between total and anteroposterior sway speed and squat speed was stronger under dual task. Clinicians and researchers should consider monitoring squat speed and depth when assessing dynamic balance during single-leg squats, as these parameters influence postural control, especially under dual task.

Comparison of the Effect of the Combined Mechanism Ankle Support on Static and Dynamic Postural Control of Chronic Ankle Instability Patients

BACKGROUND

Chronic ankle instability (CAI) is associated with postural control impairment. Orthotic devices are routinely used to improve postural control of CAI patients and prevent recurrence of ankle sprain. This study aimed to evaluate and compare the effect of combined mechanism ankle support (CMAS) with soft ankle support (SAS) and custom-molded foot orthosis (CFO) on static and dynamic postural control in patients with CAI.

METHODS

Twenty-two patients with CAI and 22 matched healthy subjects were recruited. The participants were evaluated in four orthotic conditions (without orthosis and with the CMAS, SAS, and CFO). Static balance was investigated in single-limb stance on the force platform, and dynamic balance was assessed using the Star Excursion Balance Test (SEBT).

RESULTS

Statistically significant differences were found for the main effects of the groups in all center of pressure (COP) parameters and reach distances in medial (M), anteromedial (AM), and posteromedial (PM) directions of the SEBT ( P < .05). The main effect of the orthotics for all evaluated parameters, except reach distance in the PM direction, was statistically different. All COP parameters were significantly lower with the CMAS compared with other orthotic conditions in CAI patients. Also, the higher reach distances with the CMAS were obtained in the AM and M directions of the SEBT.

CONCLUSION

The CMAS improved impaired postural control in static and dynamic stability tests, but no similar effect was found for SAS and CFO. This result may have implications for the best bracing for CAI.

LEVEL OF EVIDENCE

Level II, comparative study.

A Review of Field-Based Assessments of Neuromuscular Control and Their Utility in Male Youth Soccer Players

Read, PJ, Oliver, JL, Croix, MS, Myer, GD, and Lloyd, RS. A review of field-based assessments of neuromuscular control and their utility in male youth soccer players. J Strength Cond Res 33(1): 283-299, 2019-Lower-extremity injuries in male youth soccer are common and equate to a substantial time loss from training and competitions during the course of a season. Extended periods of absence will impact player involvement in skill and physical development activities, as well as participation in competitive match play. Neuromuscular risk factors for lower-extremity injury in male youth soccer players can be categorized into quadriceps dominance, leg dominance, ligament dominance, trunk dominance, and reduced dynamic stability. Valid screening methods to identify risk factors that are practically viable are needed for youth athletes who may be at a greater risk of injury in soccer. Although field-based tests of neuromuscular control provide a reliable option for the assessment of injury risk in adults and females, less data are available in male youth soccer players, and further research is required to examine their ability to predict injury risk. This article provides a review of the current literature pertaining to field-based screening tests and critically appraises their suitability for use with male youth soccer players. Currently, the only method that has been validated in male youth soccer players is the landing error scoring system. Asymmetrical anterior reach measured during the Y-Balance test may also be considered because of its strong predictive ability in male youth basketball players; however, further research is required to fully support its use with soccer players.

The effects of total ankle arthroplasty on postural stability and loading symmetry in quiet stance

Ankle osteoarthritis is a debilitating condition affecting about 1% of the population with approximately 50,000 new instances annually. One treatment is total ankle arthroplasty (TAA), however, its effects on balance are not well understood. This study analyzed balance over a two-year period following TAA. 408 subjects (177 left, 231 right ankles) diagnosed with end-stage ankle osteoarthritis performed quiet standing trials while center of pressure (COP) data were collected. Data were compared across three time points (pre-op, 1-year, and 2-years post-op) and between surgical and non-surgical limbs using a linear mixed model with significance set at P = 0.05. COP excursions in the feet-together condition were not significantly different between limbs after 2 years in anteroposterior or mediolateral directions (P = 0.06, 0.08) after being significantly different between limbs in the anteroposterior (P = 0.014) and mediolateral direction (P < 0.001) pre-op. The vertical ground reaction force significantly decreased across time in the non-surgical limb, while reciprocally increasing in the surgical limb (P < 0.001). After 2 years, no significant difference in vertical ground reaction force between limbs existed (P = 0.20). Limb asymmetry indices decreased at each time point in both conditions (all P < 0.001) and were not significantly different from zero after 2 years in the feet-together condition (P = 0.290). In conclusion, surgical limb balance improved compared to pre-op, resulting in increased symmetry between limbs after 2 years. Vertical ground reaction forces on both limbs converge and limb asymmetry indices approach zero two years post-op. Differences in the COP excursion-loading symmetry relationship between limbs could be useful for identifying instability in other pathologies.

Effects of Peroneal Muscles Fatigue on Dynamic Stability Following Lateral Hop Landing: Time to Stabilization Versus Dynamic Postural Stability Index

CONTEXT

Dynamic stability is a necessary requirement in many sports competitions. Muscle fatigue, which can impair stability, may be occurred in many sports competitions in which lateral movements and landing repeated frequently.

OBJECTIVE

To assess the effects of peroneal muscles fatigue on dynamic stability following lateral hop landing through measuring time to stabilization (TTS) and dynamic postural stability index (DPSI).

DESIGN

Quasi-experimental.

SETTING

Laboratory study.

PARTICIPANTS

A total of 20 recreationally active, healthy males with no lower-extremity injury during the previous 6 months participated in this study.

INTERVENTION

Participants performed a lateral hop on a force plate before and immediately after a fatigue intervention using a Biodex dynamometer. For inducing fatigue, the participant made a prolonged eversion effort with 40% of the maximal voluntary contraction. Fatigue was met when the eversion torque declined by 50% of the initial value. TTS and DPSI were calculated using sequential averaging method and relevant formulas, respectively.

MAIN OUTCOME MEASURES

Premeasures and postmeasures of TTS in the anteroposterior, mediolateral and vertical directions, resultant vector of TTS, stability indices in the anteroposterior, mediolateral and vertical directions, and DPSI.

RESULTS

Means of the DPSI or its components did not change significantly due to fatigue (P > .05). Means of the TTS in the anteroposterior and mediolateral directions, and the mean of the resultant vector of the TTS increased significantly after fatigue (P < .05).

CONCLUSIONS

The question that the dynamic stability is affected or not affected by fatigue depends on which of the TTS or DPSI is used for analysis. The TTS may be a sensitive measure to detect subtle changes in postural stability due to fatigue. But, the DPSI which may be changed after a more strenuous fatigue may be related to actual fatiguing situations.

Responsiveness of a Persian version of Knee Injury and Osteoarthritis Outcome Score and Tegner activity scale in athletes with anterior cruciate ligament reconstruction following physiotherapy treatment

PURPOSE

To evaluate the responsiveness and determine the minimal clinically important changes (MCICs), anchored by the patient response to a 7-point global rating scale, for Knee Injury and Osteoarthritis Outcome Score (KOOS), and Tegner activity scale in athletes undergoing physiotherapy treatment after anterior cruciate ligament reconstruction (ACL-R). Methods: Fifty-four patients undergoing physiotherapy completed the Persian versions of KOOS and Tegner scales at weeks 6 and 10 post ACL-R. The 7-point global rating of change was also completed at week 10. Responsiveness was calculated via receiver operating characteristic curve and correlation analysis. Results: Acceptable responsiveness was reached by the KOOS sports and recreation subscale (Sport/Rec) (area under the curve (AUC) = 0.72; Gamma = 0.37) and Tegner scale (AUC = 0.75; Gamma = 0.59). The MCIC scores of KOOS subscales and Tegner scale were reported. Conclusion: Our findings demonstrated that the KOOS Sport/Rec subscale and Tegner scale have adequate responsiveness between weeks 6 and 10 of physiotherapy. Therefore, these scales should be used to evaluate the effects of physiotherapy treatment and the changes in activity levels in this population. The MCIC scores of the KOOS and Tegner scale can be used to detect changes significant to the patient while avoiding limitations of other methods.

Nonlinear Dynamic Measures for Evaluating Postural Control in Individuals With and Without Chronic Ankle Instability

This study aimed to compare time-to-boundary and sample entropy during a single-leg balance task between individuals with chronic ankle instability (CAI), lateral ankle sprain copers, and healthy controls. Twenty-two participants with CAI, 20 lateral ankle sprain copers, and 24 healthy controls performed a single-leg balance task during an eyes-closed condition. Participants with CAI exhibited lower time-to-boundary values compared with lateral ankle sprain copers and healthy controls. However, we did not find differences in sample entropy variables between cohorts. A decrease in time-to-boundary values in participants with CAI indicated that CAI may constrain the ability of the sensorimotor system to maintain the center of pressure within the boundaries of the base of support. However, the regularity of the center of pressure velocity time series appears not to be altered in the CAI cohort in this study.

Comparative Effectiveness of Plantar-Massage Techniques on Postural Control in Those With Chronic Ankle Instability

CONTEXT

  One of the major concerns after an acute lateral ankle sprain is the potential for development of chronic ankle instability (CAI). The existing research has determined that clinician-delivered plantar massage improves postural control in those with CAI. However, the effectiveness of self-administered treatments and the underlying cause of any improvements remain unclear.

OBJECTIVES

  To determine (1) the effectiveness of a self-administered plantar-massage treatment in those with CAI and (2) whether the postural-control improvements were due to the stimulation of the plantar cutaneous receptors.

DESIGN

  Crossover study.

SETTING

  University setting.

PATIENTS OR OTHER PARTICIPANTS

  A total of 20 physically active individuals (6 men and 14 women) with self-reported CAI.

INTERVENTION(S)

  All participants completed 3 test sessions involving 3 treatments: a clinician-delivered manual plantar massage, a patient-delivered self-massage with a ball, and a clinician-delivered sensory brush massage.

MAIN OUTCOME MEASURE(S)

  Postural control was assessed using single-legged balance with eyes open and the Star Excursion Balance Test.

RESULTS

  Static postural control improved (P ≤ .014) after each of the interventions. However, no changes in dynamic postural control after any of the interventions were observed (P > .05). No differences were observed between a clinician-delivered manual plantar massage and either a patient-delivered self-massage with a ball or a clinician-delivered sensory brush massage in any postural-control outcome.

CONCLUSIONS

  In those with CAI, single 5-minute sessions of traditional plantar massage, self-administered massage, and sensory brush massage each resulted in comparable static postural-control improvements. The results also provide empirical evidence suggesting that the mechanism for the postural-control improvements is the stimulation of the plantar cutaneous receptors.

Advanced conservative treatment of complete acute rupture of the lateral ankle ligaments: Verifying by stabilometry

BACKGROUND

The aim of this study was to investigate the result of the specific conservative treatment of acute lateral ankle ligaments rupture and verify the effect of this therapy by stabilometry.

METHODS

17 young athletes were examined after acute lateral ankle sprain (grade III). Diagnosis was based on musculoskeletal ultrasound examinations. Pressure plate evaluated postural stability after conservative treatment at regular intervals during 1year.

RESULTS

There were no significant differences in postural stability in double-leg stance between limbs. In single-leg stance, COP confidence ellipse (p=0,011) and COP excursion in sagittal plane (p=0,000) were significantly higher for the injured leg when compared with the uninjured leg only one week after removing the cast.

CONCLUSIONS

After conservative treatment of grade III injuries with STABHA, immobilization with full weight bearing on the injured leg for 6 weeks and rehabilitation, stabilometry results showed that none of the patients had impaired postural stability or were at risk of functional ankle instability in the monitored period.

Landing Kinematics and Kinetics at the Knee During Different Landing Tasks

CONTEXT

  Several tasks have been used to examine landing biomechanics for evaluation and rehabilitation, especially as related to anterior cruciate ligament injuries. However, comparing results among studies in which different tasks were used can be difficult, and it is unclear which task may be most appropriate.

OBJECTIVE

  To compare lower extremity biomechanics across 5 commonly used landing tasks.

DESIGN

  Descriptive laboratory study.

SETTING

  University-operated US Air Force Special Operations Forces human performance research laboratory.

PATIENTS OR OTHER PARTICIPANTS

  A total of 65 US Air Force Special Tactics Operators (age = 27.7 ± 5.0 years, height = 176.5 ± 5.7 cm, mass = 83.1 ± 9.1 kg).

INTERVENTION(S)

  Kinematic and kinetic analysis of double- and single-legged drop landing, double- and single-legged stop jump, and forward jump to single-legged landing.

MAIN OUTCOME MEASURE(S)

  Hip-, knee-, and ankle-joint kinematics; knee-joint forces and moments; and ground reaction forces (GRFs) were the dependent measures. We used repeated-measures analyses of variance or Friedman tests, as appropriate, to assess within-subject differences across tasks.

RESULTS

  Peak vertical GRF and peak knee-flexion angle were different among all tasks ( P < .001). Single-legged landings generated higher vertical GRF (χ² = 244.68, P < .001) and lower peak knee-flexion values ( F_4,64 = 209.33, P < .001) except for forward jump to single-legged landing, which had the second highest peak vertical GRF and the lowest peak knee-flexion value. The single-legged drop landing generated the highest vertical (χ² = 244.68, P < .001) and posterior (χ² = 164.46, P < .001) GRFs. Peak knee-valgus moment was higher during the double-legged drop landing (χ² = 239.63, P < .001) but similar for all others.

CONCLUSIONS

  Different landing tasks elicited different biomechanical responses; no single task was best for assessing a wide range of biomechanical variables related to anterior cruciate ligament injuries. Therefore, depending on the goals of the study, using multiple assessment tasks should be considered.

Test-retest reliability of a balance testing protocol with external perturbations in young healthy adults

External perturbations are utilized to challenge balance and mimic realistic balance threats in patient populations. The reliability of such protocols has not been established. The purpose was to examine test-retest reliability of balance testing with external perturbations. Healthy adults (n=34; mean age 23 years) underwent balance testing over two visits. Participants completed ten balance conditions in which the following parameters were combined: perturbation or non-perturbation, single or double leg, and eyes open or closed. Three trials were collected for each condition. Data were collected on a force plate and external perturbations were applied by translating the plate. Force plate center of pressure (CoP) data were summarized using 13 different CoP measures. Test-retest reliability was examined using intraclass correlation coefficients (ICC) and Bland-Altman plots. CoP measures of total speed and excursion in both anterior-posterior and medial-lateral directions generally had acceptable ICC values for perturbation conditions (ICC=0.46 to 0.87); however, many other CoP measures (e.g. range, area of ellipse) had unacceptable test-retest reliability (ICC<0.70). Improved CoP measures were present on the second visit indicating a potential learning effect. Non-perturbation conditions generally produced more reliable CoP measures than perturbation conditions during double leg standing, but not single leg standing. Therefore, changes to balance testing protocols that include external perturbations should be made to improve test-retest reliability and diminish learning including more extensive participant training and increasing the number of trials. CoP measures that consider all data points (e.g. total speed) are more reliable than those that only consider a few data points.

Functional donor site morbidity longer than one year after fibula free flap: A prospective biomechanical analysis

OBJECTIVES

The fibula free flap is the workhorse procedure for osseous reconstruction. The objective of this study was to investigate long-term functional outcomes of the harvesting site.

PATIENTS AND METHODS

About 19 patients (10 male, 9 female, mean age 58.1 years) were available for the long-term analysis 13-51 months after surgery. Jumping mechanography and balance testing on a ground force reaction plate (Leonardo Mechanograph GFRP) were performed before and surgery. The Esslinger Fitness Index (EFI, maximum peak power in W/kg normalized for age and gender) was considered as primary endpoint. Secondary outcomes were maximum force, range of motion in the ankle joint, sensory limitations, the American Orthopedic Foot and Ankle Society Score (AOFAS-Score), and subjective perceptions.

RESULTS

We found no significant difference between pre- and postoperative EFI (70.4% versus 66.0%, P = 0.07) and body sway (1.72 cm² versus 2.60 cm² , P = 0.093). The AOFAS-Score was reduced by 8.8 points (99.1 points versus 90.3 points, P < 0.001). Dorsal extenstion (31.6° versus 24.1°, P < 0.001) and flexion (32.3 versus 25.6° flexion, P = 0.011) were significantly reduced and 6 patients had chronic pain.

CONCLUSIONS

Reduced peak power and balance ability seem to be reversible short-term effects after fibula harvesting. We recommend preoperative patient education and standardized protocols for physiotherapy.

Comparison of jump-landing protocols with Biodex Balance System as measures of dynamic postural stability in athletes

The objective of the study was to determine whether a relationship exists between the two common methods for assessing postural stability in athletes: the time-to-stabilisation (TTS) via force-plate and the Biodex Balance System (BBS). The conditions under which these measurements assess dynamic postural control may not provide sufficient feedback to practitioners. Fourty-four amateur soccer players with no history of musculoskeletal disorders volunteered for the study. Pearson correlation was used to compare the anterior-posterior (AP), medio-lateral (ML), and the overall stability indexes measured by BBS, with the corresponding parameters of TTS assessed via force plate. There was no significant correlation between any parameters of dynamic stability measured by force-plate and the stability indexes. However, there was a significant correlation between the resulting vectors and the AP component of TTS for each jump protocol. Furthermore, forward drop landing exhibited shortest TTS in AP direction, while lateral drop landing resulted in longer ML TTS relative to both forward jumps (p < 0.001). These results demonstrate that the TTS and BBS stability indexes should be used as distinct measures of dynamic postural stability. TTS protocols may be modified to target a specific training conditions or athletic population.

Comparison Between Single and Combined Clinical Postural Stability Tests in Individuals With and Without Chronic Ankle Instability

OBJECTIVE

To determine if a single or/and combined clinical tests match group membership based on self-reported ankle function.

DESIGN

Cross-sectional.

SETTING

Biomechanics Laboratory.

PARTICIPANTS

From participants, 58 meeting inclusion/exclusion criteria were divided into a chronic ankle instability (CAI) group (n = 25) who reported ≤25 on the Cumberland Ankle Instability Tool (CAIT) and a history of moderate-severe ankle sprain(s) and a control group (n = 33) who reported ≥29 on the CAIT and no history of ankle sprain(s).

INTERVENTIONS

Participants completed the following clinical tests: Foot Lift Test (FLT), the Star Excursion Balance Test (SEBT), the Single-Leg Hop Test (SLHT), and the Time in Balance Test (TIB) in a randomized order. A linear regression model was applied to determine measures that matched ankle group membership.

MAIN OUTCOME MEASURES

The mean of SEBT reach distance was normalized to percentage leg length. The mean of number of errors in the FLT was recorded. The SLHT and TIB were reported as time in seconds, and the means were calculated.

RESULTS

The most parsimonious combination of tests (SLHT and SEBT) resulted in correctly matching 70.69% (41/58) of participants into groups, which was significantly better than chance. The multiple correlation coefficients (R value) for combining the SLHT and SEBT was 0.39.

CONCLUSIONS

Using SLHT and SEBT resulted in improved recognition of participants designated into the CAI or control groups. Self-report perception of ankle function provides limited information for clinicians and researchers. Using multiple clinical function tests may be more helpful in determining deficits and intervention effectiveness.

Attention is associated with postural control in those with chronic ankle instability

Chronic ankle instability (CAI) is often debilitating and may be affected by a number of intrinsic and environmental factors. Alterations in neurocognitive function and attention may contribute to repetitive injury in those with CAI and influence postural control strategies. Thus, the purpose of this study was to determine if there was a difference in attentional functioning and static postural control among groups of Comparison, Coper and CAI participants and assess the relationship between them within each of the groups. Recruited participants performed single-limb balance trials and completed the CNS Vital Signs (CNSVS) computer-based assessment to assess their attentional function. Center of pressure (COP) velocity (COPv) and maximum range (COPr), in both the anteroposterior (AP) and mediolateral (ML) directions were calculated from force plate data. Simple attention (SA), which measures self-regulation and attention control was extracted from the CNSVS. Data from 45 participants (15 in each group, 27=female, 18=male) was analyzed for this study. No significant differences were observed between attention or COP variables among each of the groups. However, significant relationships were present between attention and COP variables within the CAI group. CAI participants displayed significant moderate to large correlations between SA and AP COPr (r=-0.59, p=0.010), AP COPv (r=-0.48, p=0.038) and ML COPr (r=-0.47, p=0.034). The results suggest a linear relationship of stability and attention in the CAI group. Attentional self-regulation may moderate how those with CAI control postural stability. Incorporating neurocognitive training focused on attentional control may improve outcomes in those with CAI.

Effect of cognitive task on postural control of the patients with chronic ankle instability during single and double leg standing

OBJECTIVE

The aim of this study was to investigate the effect of a cognitive task on standing postural control of the injured and non-injured leg of athletes with chronic ankle instability.

METHODS

Postural stability was measured by center of pressure parameters while chronic ankle instability patients (n = 8) randomly performed single and double leg standing in isolation or concurrently with a digit-backward cognitive task.

RESULTS

After performing a concurrent cognitive task, anteroposterior sway significantly decreased in injured leg (P < 0.05) and area significantly decreased in both injured and non-injured legs (P < 0.05). There was no significant difference in all center of pressure parameters between injured and non-injured legs.

CONCLUSION

The findings confirm the effect of a concurrent digit-backwards memory task on single leg standing balance in chronic ankle instability patients but the response to cognitive loading was not significantly different between the injured and non-injured legs.

Evidence of a different landing strategy in subjects with chronic ankle instability

The purpose of the study is to evaluate the discriminative validity of the multiple hop test (MHT) for chronic ankle instability (CAI). The dynamic postural control of 51 CAI subjects and 52 uninjured controls was assessed using the MHT. To evaluate dynamic postural control, the type and number of balance errors were analysed and the time to complete the MHT was measured. Between-group differences of time scores and balance errors, identified as being change-in-support strategy errors (CSS) or fixed-support strategy errors (FSS), were assessed. The area under curve of the outcomes was determined and likelihood ratios (LRs) were calculated based upon their most optimal cut off point. When compared to uninjured controls, CAI subjects needed significantly more time to perform the test (p<0.001) and made significantly more CSS errors (p<0.001). When 1 positive outcome (time score or CSS errors) was considered as a criterion, the LR⁺ was 2 and the LR^- 0.08. In the case of 2 positive outcomes (time score and CSS errors), the LR⁺ was 7.1 and the LR^- 0.49. CAI subjects have an impaired dynamic postural control and rely on a different postural strategy to restore balance. The MHT has good discriminative validity for CAI.

Consistency of Field-Based Measures of Neuromuscular Control Using Force-Plate Diagnostics in Elite Male Youth Soccer Players

Read, P, Oliver, JL, Croix, MD, Myer, GD, and Lloyd, RS. Consistency of field-based measures of neuromuscular control using force-plate diagnostics in elite male youth soccer players. J Strength Cond Res 30(12): 3304-3311, 2016-Deficits in neuromuscular control during movement patterns such as landing are suggested pathomechanics that underlie sport-related injury. A common mode of assessment is measurement of landing forces during jumping tasks; however, these measures have been used less frequently in male youth soccer players, and reliability data are sparse. The aim of this study was to examine the reliability of a field-based neuromuscular control screening battery using force-plate diagnostics in this cohort. Twenty-six pre-peak height velocity (PHV) and 25 post-PHV elite male youth soccer players completed a drop vertical jump (DVJ), single-leg 75% horizontal hop and stick (75%HOP), and single-leg countermovement jump (SLCMJ). Measures of peak landing vertical ground reaction force (pVGRF), time to stabilization, time to pVGRF, and pVGRF asymmetry were recorded. A test-retest design was used, and reliability statistics included change in mean, intraclass correlation coefficient, and coefficient of variation (CV). No significant differences in mean score were reported for any of the assessed variables between test sessions. In both groups, pVGRF and asymmetry during the 75%HOP and SLCMJ demonstrated largely acceptable reliability (CV ≤ 10%). Greater variability was evident in DVJ pVGRF and all other assessed variables, across the 3 protocols (CV range = 13.8-49.7%). Intraclass correlation coefficient values ranged from small to large and were generally higher in the post-PHV players. The results of this study suggest that pVGRF and asymmetry can be reliably assessed using a 75%HOP and SLCMJ in this cohort. These measures could be used to support a screening battery for elite male youth soccer players and for test-retest comparison.

Time series of ground reaction forces following a single leg drop jump landing in elite youth soccer players consist of four distinct phases

The single leg drop jump landing test may assess dynamic and static balance abilities in different phases of the landing. However objective definitions of different phases following landing and associated reliability are lacking. Therefore, we determined the existence of possible distinct phases of single leg drop jump landing on a force plate in 82 elite youth soccer players. Three outcome measures were calculated over moving windows of five sizes: center of pressure (COP) speed, COP sway and horizontal ground reaction force (GRF). Per outcome measure, a Factor Analysis was employed with all windows as input variables. It showed that four factors (patterns of variance) largely (>75%) explained the variance across subjects/trials along the 12s time series. Each factor was highly associated with a distinct phase of the time series signal: dynamic (0.4-2.7s), late dynamic (2.5-5.0s), static 1 (5.0-8.3s) and static 2 (8.1-11.7s). Intra-class correlations (ICC) between trials were lower for the dynamic phases (0.45-0.68) than for the static phases (0.60-0.86). The COP speed showed higher ICC's (0.63-0.86) than COP sway (0.45-0.61) and GRF (0.57-0.71) for all four phases. In conclusion, following a drop jump landing unique information is available in four distinct phases. The COP speed is most reliable, with higher reliability in the static phases compared to the dynamic phases. Future studies should assess the sensitivity of information from dynamic, late dynamic and static phases.

Changes in Postural Control After a Ball-Kicking Balance Exercise in Individuals With Chronic Ankle Instability

CONTEXT

Rehabilitation programs for patients with chronic ankle instability (CAI) generally involve balance-perturbation training (BPT). Anticipatory postural adjustments (APAs) and compensatory postural adjustments (CPAs) are the primary strategies used to maintain equilibrium during body perturbations. Little is known, however, about how APAs and CPAs are modified to promote better postural control for individuals with CAI after BPT.

OBJECTIVE

To investigate the effect of BPT that involves kicking a ball on postural-control strategies in individuals with CAI.

DESIGN

Randomized controlled clinical trial.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

We randomly assigned 44 volunteers with CAI to either a training group (TG; 11 women, 11 men; age = 24 ± 4 years, height = 173.0 ± 9.8 cm, mass = 72.64 ± 11.98 kg) or control group (CG; 11 women, 11 men; age = 22 ± 3 years, height = 171.0 ± 9.7 cm, mass = 70.00 ± 11.03 kg).

INTERVENTION(S)

The TG performed a single 30-minute training session that involved kicking a ball while standing on 1 foot. The CG received no intervention.

MAIN OUTCOME MEASURE(S)

The primary outcome was the sum of the integrated electromyographic activity (∑∫EMG) of the lower extremity muscles in the supporting limb that were calculated during typical intervals for APAs and CPAs. A secondary outcome was center-of-pressure displacement during similar intervals.

RESULTS

In the TG after training, the ∑∫EMG decreased in both dorsal and ventral muscles during compensatory adjustment (ie, the time interval that followed lower limb movement). During this interval, muscle activity (∑∫EMG) was less in the TG than in the CG. Consequently, center-of-pressure displacement increased during the task after training.

CONCLUSIONS

A single session of ball-kicking BPT promoted changes in postural-control strategies in individuals with CAI. These results should stimulate new and more comprehensive studies to investigate the effect of this and other BPT techniques on postural control in patients with CAI.

PERONEUS LONGUS ACTIVITY IN DIFFERENT TYPES OF TAPING: ATHLETES WITH ANKLE INSTABILITY

ABSTRACT Introduction: Participation in sport among university athletes in Malaysia has progressed right up to Olympic level. However, some of these athletes are prevented from competing due to injuries. Ankle injuries, in particular, are among the common types of injury. Even so, there is still lack of local data and research describing the incidence of ankle injuries. Objectives: To determine peroneus longus muscle activity in different taped ankles and positions among subjects with functional ankle instability (FAI). Methods: Twenty-three subjects with ankle instability (AJFAT score > 26) volunteered to take part in the study. The subjects were tested under three conditions; 1) no tape (NT), 2) Kinesio(r) tape (KT), and 3) rigid tape (RT). The subjects completed two postural stability tests, followed by a sudden inversion perturbation test with EMG, recording throughout the procedures. The EMG data were analyzed, filtered, full-wave rectified and normalized. The data were analyzed by analysis of variance (Independent T-test and ANOVA) to evaluate differences in peak muscle activation (mV) and peroneal latency (ms). Results: Peak muscle activation of the peroneus was activated more in the RT group during both the Static and Dynamic Stability Tests. Apart from that, there were no statistically significant differences. During sudden inversion perturbation, the RT group was the one that was most activated (p=0.001). Peroneal latency was even delayed in KT and RT during the three tests, and shorter in the NT group. There were significant differences during the Dynamic Stability Test, between the NT and KT groups (p=0.001) and between the NT, RT and KT groups (p=0.001). Conclusion: RT tape may enhance the peroneus longus response by maintaining a higher level of muscle activation, especially during dynamic movements and sudden inversion of the ankle, and may selectively benefit individuals with FAI. The KT ankle did not show superior effect to the NT ankle, and demonstrated minimal benefit when used in FAI. Also, its use may be more likely to cause reinjury to the ankle.

The Hemi-Castaing ligamentoplasty for chronic lateral ankle instability does not modify proprioceptive, muscular and posturographic parameters

PURPOSE

The Hemi-Castaing ligamentoplasty uses a powerful dynamic stabilizer of the ankle which is the peroneus brevis tendon. To our knowledge, there is no study available evaluating the effects of this type of surgery on proprioceptive, muscular and posturographic parameters.

METHODS

This case-control study included 39 subjects divided into two groups: the operated (n = 24) and the control group (n = 15). All subjects underwent a clinical, proprioceptive and isokinetic assessment using a CON-TREX dynamometer, and a postural evaluation using the Win-Posturo force platform.

RESULTS

At a mean period of 23 (SD 5.4) post-operative months, the Karlsson ankle functional score was 84.2 (SD 23.8) and the AOFAS score was 88.1 (SD 16.2). The mean ankle joint position error for operated ankles was from 1.9° (SD 0.9) at 10° of inversion range of motion to 2.5° (SD 1.7) at 20°. It was similar to that achieved in the control group ranging from 2.2° (SD 1) at 10° to 2.3° (SD 1.3) at 20°. No significant loss of ankle eversion strength could be observed after ligamentoplasty. Ankle eversion/inversion ratio when tested under all velocities and contraction modes failed to reveal any statistical difference between the operated and healthy ankles in the patient group, neither between the patient and control groups.

CONCLUSIONS

This surgical technique achieved excellent functional outcomes. It did not impair the agonist/antagonist balance of ankle muscles, and use of half the peroneus brevis tendon did not lessen the eversion strength.

LEVEL OF EVIDENCE

Case-control study, Level III.