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BACKGROUND: It is important for clinicians and researchers to perform dynamic postural control evaluation for predicting musculoskeletal conditions, injury prevention, and rehabilitation. OBJECTIVE: The purpose of this study was to investigate the relationship (1) between the eccentric strength of the knee extensors and star excursion balance test (SEBT), and (2) between the knee proprioception and SEBT. METHODS: Forty healthy young adults participated in this study. The eccentric peak torque (EPT) of the knee extensors, joint position sense, and force sense were measured. The participants also performed SEBT. Pearson’s product-moment correlation and multiple linear regression analysis were used to determine the relationship between the variables and SEBT. RESULTS: The posteromedial direction of the SEBT was positively and strongly correlated with EPT (r= 0.74, P< 0.01). The anterior and posterolateral directions were positively and moderately correlated with EPT (r= 0.46, P< 0.01, and r= 0.69, P< 0.01, respectively.). However, knee proprioception was not correlated with all the directions of SEBT (P> 0.05). According to the results of multiple linear regression analysis, EPT of the knee extensors significantly predicted SEBT reach distances. CONCLUSION: The eccentric strength of the knee extensors seems to be an essential factor in dynamic postural control. However, the knee proprioception did not show a significant correlation with SEBT.

Background: Postural control deficit is a major characteristic in patients with chronic ankle instability (CAI). Elastic ankle tapings are commonly used to facilitate postural control in patients with CAI as well as prevent relapse of a lateral ankle sprain. However, equivocal evidence exists concerning the effect of elastic ankle taping on postural control. Objects: This study aimed to evaluate the effects of elastic ankle tapings using kinesio taping (KT) and dynamic taping (DT) on static and dynamic postural control in patients with CAI. Methods: Fifteen subjects with CAI were participated in this study. The participants performed tests under three conditions (barefoot, KT, and DT). Static postural control was evaluated using the one-leg standing test (OLST) and dynamic postural control using the modified Star Excursion Balance Test (mSEBT). One-way repeated-measures analysis of variance was used to compare center of pressure (CoP) data and normalized mSEBT reach distances among the three conditions (with α = 0.05). Results: The CoP parameters (path length, ellipse area, and mean velocity) of the OLST significantly decreased on applying KT and DT compared with those when barefoot. The normalized reach distances in the anteromedial (AM), medial (M), and posteromedial (PM) directions of the mSEBT significantly increased with DT compared to that in the control condition. Further, the higher reach distances with KT compared with those in the control condition were obtained in the M and PM directions of the mSEBT. No significant differences were identified in any of the OLST and SEBT parameters between the two different taping applications. Conclusion: KT and DT improved static postural control during the OLST compared with the control condition. Moreover, these tapes improved dynamic postural control during the mSEBT compared to the control. Therefore, elastic ankle tapings are useful prophylactic devices for the prevention and treatment of ankle sprain in people with CAI.

An empirical consensus of differences between chronic ankle instability (CAI) individuals and copers (individuals who sprained ankle once and without recurrent symptoms or injury) has not been reported. This study aimed to review the locomotion biomechanics and dynamic postural control between these two populations. Database of ScienceDirect, PubMed and Web of Science was used to search ('chronic ankle instability' OR 'ankle instability') AND ('ankle sprain' OR 'coper*') until 30 November 2020. Articles that made a comparison about changes in biomechanical parameters between Copers and CAI individuals during locomotor or functional tasks were included in this review. Twenty-three articles met the inclusion criteria. CAI individuals exhibited an increased hip flexion to maintain stability, suggesting the adopted hip strategy compared to copers during landing. Dorsiflexion angle and ankle frontal displacement increased considerably compared to copers, which might increase risks of lateral ankle sprain injury. CAI individuals reduced the ankle displacements in the sagittal plane and indicated worse performance of Star Excursion Balance Test in the posterior-lateral direction compared to copers. Identified motion deficits or altered motion strategies provide opportunities for targeted intervention and scheme after index sprain or in CAI individuals.

We investigated the influence of sex and age in postural sway during sit-to-stand (STS) in children and adolescents of 5-15 years. We evaluated sway during STS in 86 typical participants. STS was divided into three phases: preparation, rising, and stabilization. We calculated for each phase: area, anterior-posterior, and medial-lateral velocity of center-of-pressure sway. We applied a stepwise multiple linear regression model to determine if age and sex might be predictors of postural sway during STS. Only age was associated with sway, accounting for between 6.5% and 14.6% of the variability in sway during STS. The age of the subject influences postural sway during STS, but in a small amount. This variable should be taken into account as a variable of control in the assessment of dynamic postural control. Moreover, postural stability during STS was not associated with the sex of the participants.

The purpose of this study was to determine how the application of static stretching to ankle plantar flexors affects postural control during maximum forward leaning. Twenty-six volunteer males (age 21.4 ± 1.2 years) were randomly assigned to stretching and control conditions. Participants conducted 5-min stretching on a stretch board for the stretching condition and were kept standing for 6-min for the control condition. Before and after intervention, the range of motion (ROM) at ankle dorsiflexion and the center of pressure (COP) excursion during maximal forward leaning were determined. Mean anteroposterior COP position, COP velocity and COP areas were calculated to compare the change in postural control. After stretching, ROM was significantly increased. During maximal forward leaning after stretching, both COP position and velocity showed significant increases compared to before stretching. Moreover, COP position and velocity in the stretching condition were significantly higher than in the control condition after stretching. No significant differences were found in COP area before and after stretching. Five-minute stretching increased not only ROM but also the anterior limit of stability while maintaining posture and led to faster COP shift than before stretching. These results indicate that static stretching would improve dynamic postural control as well.

The purpose of this study was to investigate whether low-handicap elite golfers with chronic low back pain (CLBP) exhibit deficits in dynamic postural control and whether CLBP affects golfers in terms of their golf swing parameters. A total of fifteen Division 1 college golfers were recruited as participants. Of these, six of whom experienced CLBP, while the remaining participants were healthy. In this study, CLBP was defined as experiencing chronic pain symptoms for more than six months. The Star Excursion Balance Test (SEBT) was administered to examine dynamic posture control in both groups. The TrackMan Golf Launch Monitor Simulator was used to collect data on the performance parameters of the swing of the participants. The results for both feet in the medial, lateral, posterior, posteromedial, and posterolateral directions indicated that the CLBP group scored lower than the control group. However, the CLBP group scored higher for the right foot in the anterolateral direction. The parameters for the club speed and ball carry of the CLBP group were lower than those of the control group. Further, the CLBP group exhibited a more upright swing plane relative to the control group. Taken together, our findings suggest that SEBT may be feasible and highly accessible to assess golf swing performance of elite players with CLBP. Key points Elite golfers with CLBP exhibit poor performance for both feet in the M, L, P, PM, and PL directions but good performance for the back foot in the AL direction and are thus able to compensate for the influence of CLBP. Regarding swing performance, the CLBP group exhibited unsatisfactory club speed and ball carry. In addition, this group tended to produce a more upright swing plane. Our findings suggest that SEBT may be feasible and highly accessible to assess golf swing performance of elite players with CLBP.

Highlights • There was an association between eye tracking and clinical concussion symptoms. • The concussion group with eye tracking deficits had a worse overall total symptom severity compared to the normal eye tracking group and healthy controls. • Severity scores in each of the 5 symptom profiles were also higher in the concussion group with impaired eye tracking, but it does not appear that eye tracking deficits are influenced by one symptom domain in particular. • The abnormal eye tracking group walked with a slower single-task and dual-task gait speed, but the difference in gait speed was not statistically significant., Purpose The purpose of the study was to (1) examine the relationship between self-reported symptoms and concussion-related eye tracking impairments, and (2) compare gait performance between (a) adolescents with a concussion who have normal eye tracking, (b) adolescents with a concussion who have abnormal eye tracking, and (c) healthy controls. Methods A total of 30 concussed participants (age: 14.4 ± 2.2 years, mean ± SD, 50% female) and 30 controls (age: 14.2 ± 2.2 years, 47% female) completed eye tracking and gait assessments. The BOX score is a metric of pupillary disconjugacy, with scores, Graphical Abstract Image, graphical abstract

OBJECTIVE: To determine the value of a traditional (easy to implement) group-based intervention program on both static and dynamic postural control in children with Developmental Coordination Disorder (DCD). METHODS: Sway and stability indices were measured with the Clinical Test of Sensory Integration in Balance (CTSIB) and efficiency of goal-directed movement was measured during a Limits-of-Stability (LoS) task, before and after the intervention program. The intervention involved a total of 10 one-hour group sessions, administered once per week for 10 weeks. RESULTS: Results indicated significant group increases in dynamic postural control (p < .05). These results suggest it is possible to improve dynamic postural control in this population. This type of intervention does not require any expensive materials, it is feasible, and easy-to-implement to a group of children. CONCLUSION: We conclude that this simple form of intervention involving fun group activities can significantly improve dynamic postural control in children with DCD.

BACKGROUND Improving dynamic postural stability after lateral ankle sprain due to chronic ankle instability helps prevent recurrence, and changes in dynamic postural stability can be assessed with the Star Excursion Balance Test. To date, no studies have examined the change in Star Excursion Balance Test score after the end of a balance training program or whether chronic ankle instability affects the rate of change. To examine the effect of chronic ankle instability on changes in Star Excursion Balance Test. score over time after a balance training program. METHODS Fifteen collegiate soccer players with chronic ankle instability selected with the Cumberland Ankle Instability Tool and ultrasonography. Participants completed a 6-week balance training program. We assessed the Star Excursion Balance Test 5 times (before and immediately after the program and 2, 4, and 6 weeks later) and examined differences in the duration of training effects by a 2-way analysis of variance, with Bonferroni correction for post hoc comparisons to explain any significant interactions. The significance level for all analyses was set at P < .05. We performed statistical analyses with SPSS version 25. RESULTS Analysis of the posterolateral and posteromedial scores in Star Excursion Balance Test showed a significant effect of time. Post hoc analysis of the posterolateral score showed that for each leg, participants reached significantly farther after the program than before (P = .012). The posterolateral scores at 2, 4, and 6 weeks after the training program did not differ from before the program, but the posteromedial score was significantly improved immediately after the program (P = .008) and also 2 (P = .004) and 4 weeks later (P = .006). CONCLUSIONS A 6-week balance training program to improve dynamic postural control can improve posterolateral and posteromedial scores in people with chronic ankle instability, and the improvements in posteromedial are still present 4 weeks after program completion.

Autistic children and adults have known differences in motor performance, including postural instability and atypical gross motor control. Few studies have specifically tested dynamic postural control. This is the first study to quantify movement smoothness and its relationship to task performance during lateral dynamic postural control tasks in autism.We sought to test the hypothesis that autistic children would have less smooth movements to lateral static targets compared to neurotypical children, and that this difference would relate to specific movement strategies.We used camera-based motion-capture to measure spatiotemporal characteristics of lateral movement of a marker placed on the C7 vertebrae, and of markers comprising trunk and pelvis segments during a dynamic postural movements to near and far targets administered in an immersive virtual environment. We tested a sample of 15 autistic children and 11 age-matched neurotypical children. We quantified movement smoothness using log dimensionless jerk.Autistic children exhibited more medial-lateral pelvic position range of motion compared to neurotypical children, and used a stepping strategy more often compared to neurotypical children. Autistic children also had higher log dimensionless jerk than neurotypical children for motion of the C7 marker. All participants had higher log dimensionless jerk for far targets than for near targets. Autistic children had longer trial durations than neurotypical children, and younger children had longer trial durations than older children across diagnostic groups.The stepping strategy observed more often in the autistic group likely contributed to log dimensionless jerk and reduced movement smoothness. This strategy is indicative of either an attempt to prevent an impending loss of balance, or an attempt to compensate for and recover from a loss of balance once it is detected.

Background Evidence is scarce concerning the relationship of physical dysfunction of the trunk and lower extremities with elbow and shoulder pain in young baseball players. This study aimed to examine the association of joint flexibility of the trunk and lower extremities and dynamic postural control with elbow and shoulder pain among elite young baseball players. Methods We analyzed baseball players (aged 9-12 years) who participated in the National Junior Sports Clubs Baseball Festival. Range of motion in external rotation and internal rotation (IR) of the hip, as well as the finger-to-floor distance and heel-to-buttock distance, was measured. The straight-leg-raise test was also conducted. Dynamic postural control was evaluated using the Star Excursion Balance Test. Multivariable logistic regression analyses were conducted to examine the association of physical function with the elbow or shoulder pain incidence. Results Of 210 players surveyed, 177 without elbow or shoulder pain were included in the analysis. Of the participants, 16 (9.0%) reported having elbow or shoulder pain during the tournament. Participants with the incidence of elbow or shoulder pain had a significant restriction in hip IR of the stride leg compared with those without pain (35.8° vs. 43.7°, P = .022). There were no significant associations of other joint flexibilities and the Star Excursion Balance Test with elbow or shoulder pain. Conclusion Decreased hip IR range of motion of the stride leg was significantly associated with the elbow or shoulder pain incidence. Players, coaches, and clinicians should consider the physical function of the trunk and lower extremities for the prevention of elbow and shoulder pain.

Thirty-two children with overweight or obesity were randomly divided into a neuromuscular training group (NTG) (n = 16) and a control group (CG) (n = 16). All individuals participated in the measurement of static postural control under two conditions: the double-leg stance with eyes open (EO) and eyes closed (EC). The center of pressure variables was obtained. mSEBT was used for dynamic postural control. Neuromuscular training was performed twice per week and lasted 4 weeks. The results of this study indicate that 4 weeks of neuromuscular training improve static and dynamic postural control in children with excess body weight.

Decreased proprioception and dynamic postural control (DPC) have been reported to be a contributing factor in anterior cruciate ligament (ACL) injuries in females. Understanding the relationship between proprioception and DPC during different phases of the menstrual cycle may provide a better understanding of gender-specific characteristics of ACL injury risk. The primary purpose of this study was to assess the relationship between DPC and both joint kinesthesia (JK) and joint position sense (JPS) in females during the ovulatory phase of the menstrual cycle. Nine moderate to highly active females. Subjects made two visits to the research facility over a two-month period. DPC, JK, and JPS were measured over two consecutive menstrual cycles during ovulatory phase (24-48 hours after LH surge detection). Joint position sense was tested using a starting angle of 90° when moving into extension, and 0° when moving into flexion. Target angles were 30°, 50°, and 70° moving into flexion, and 20°, 40°, and 60° moving into extension. Joint kinesthesia was tested moving into flexion and extension at both 15° and 45°. Moderate to high correlations were observed on six of 60 variables in the ovulatory phase of the first menstrual cycle evaluated. Although a few statistically significant correlations were identified, the clinicians may focus on those meaningful variables when they plan the rehabilitation program for prevent ACL injury. Also, while DPC deficits may increase risk of ACL injury, the data does not support that reduced DPC is due to menstrual phase-specific deficits in proprioception.

Background Voluntary movement such as lifting a foot in preparation to stepping acts as a self-initiated perturbation that disturbs postural equilibrium. To maintain and restore equilibrium, humans utilize early, anticipatory, and compensatory postural adjustments. Despite technological progress in accessible virtual reality (VR) devices, little is known on the usage of VR in control and maintenance of balance while standing. Research question How does VR modulate early, anticipatory, and compensatory postural adjustments during a dynamic task of leg lifting while avoiding an obstacle? Methods First, the postural adjustments in a single-leg obstacle avoidance were compared between real and VR settings, where a statistical reanalysis was performed with data subsets that minimize the difference of foot elevation speed. Second, the effect of simple foot elevation was examined to identify the fundamental nature of leg lifting motion as a self-initiated perturbation. Lastly, perceptual distortion in VR was assessed by evaluating how the spatial scale of the virtual scene used in the single-leg obstacle avoidance experiment was recognized by participants. Results The VR setting reduced the activities of lower leg muscles on the supporting side not only in the compensatory phase but also in the preparatory early and anticipatory phases. On the other hand, simple foot elevation resulted in a significant increase of muscle activities with lifting height only found in the compensatory phase. Furthermore, it is suggested that the VR induced perceptual distortion in estimating the sizes of the virtual objects. Significance The findings provide more definitive evidence that VR presentation modulates the components of postural adjustments for maintaining upright stance while being perturbed. One of the potential psychophysical factors is perceptual distortion in VR, and this provides critical information for further development of VR based training system.

Postural control during walking is maintained by the combination of various factors. Among these factors, adjustment of trunk movement is essential for maintaining postural control, and the response of muscles to unpredictable stimuli affects postural control. Loss of balance while walking increases the risk of accidents, the frequency of which depends on age and sex. In this study, we investigated whether there was a difference in the movement time of trunk muscles to sudden stimulation while walking according to age and sex. Fourteen healthy individuals aged 20–30 years (6 men, 8 women) and 12 individuals aged 50–70 years (4 men, 8 women) were included in the study. Movement time of bilateral erector spinae and rectus abdominis muscles in response to visual stimulation during walking was examined using surface electromyography. Movement time was calculated as the total muscle activation time excluding the reaction time. This study revealed no significant differences in movement time of the erector spinae muscles according to sex or age. The role of the rectus abdominis muscles in maintaining posture during walking was insignificant. In conclusion, the movement time of trunk muscles in response to sudden visual stimulation during walking did not differ by age or sex, and the difference in accident frequency may be associated with deterioration of other factors required to maintain posture.

Time to stabilisation (TTS) provides limited information to evaluate the dynamic postural control for individuals with functional ankle instability in single-leg landing task. More information is needed to understand TTS and evaluate the dynamic postural control better. The purpose is to develop a method estimating TTS, initial impact force (IIF) and landing leg stiffness (LLS) through fitting ground reaction force (GRF) decay in single leg landing with exponential vibration decay function (EVDF), and investigate effects of landing directions and GRF components on these parameters. Thirty-nine healthy participants were recruited. EVDF was used to fit GRF decays in different single-leg landings. TTS, IIF, and LLS were compared across landing directions and GRF components. The mean regression determinants of fitting GRF decays with EVDF were greater than 0.50. TTS was sensitive to GRF components (P = 0.041 females, P = 0.028 males). IIF was sensitive to GRF components (P = 0.001) for both genders. LLS was sensitive to GRF components (P = 0.023) for males. This method showed a moderate to strong feasibility for reporting GRF decay during landing, and provided movement characteristic information for better understanding of dynamic postural control together with TTS during landing.

Anthropometrics and sex influence balance performances, and visual information can change anthropometrics’ relation and the postural sway. Therefore, the aim of the present study was to evaluate the effect of anthropometric characteristics, sex, and visual biofeedback and/or their interaction on a computerized wobble board. Twenty-seven (14 females, 13 males) young adults performed three 30-s double leg stance trials on a wobble board during two conditions: with visual and without visual biofeedback. Visual biofeedback improved (p = 0.010) balance on a wobble board with respect to the condition without visual biofeedback. Regardless of sex, no differences between conditions were found (p = 0.088). When investigating the effect of anthropometrics variables, sex, and their interactions on conditions, a significant main effect of the lower limb/height ratio, sex, and their interaction on the condition without visual biofeedback was found (p = 0.0008, R2 = 0.57). For the visual biofeedback condition, significant effects for sex and body mass (p = 0.0012, R2 = 0.43) and sex and whole-body moment of inertia (p = 0.0030, R2 = 0.39) were found. Results from the present study showed (1) visual biofeedback improved wobble board balance performance, (2) a significant main effect of lower limb/height ratio, sex, and their interaction on the wobble board performances without visual biofeedback emerged, (3) significant effects were found for sex and body mass and sex and moment of inertia in the visual biofeedback condition. Findings from the present study could have an impact on training and evaluations protocols, especially when several populations such as children, athletes, older adults and people with balance disorders are involved.

Background Continuous oscillation of the support base requires anticipatory and reactive postural adjustments to maintain a stable balance. In this context, postural control flexibility or the ability to adjust balance mechanisms following the requirements of the environment is needed to counterbalance the predictable, continuous perturbation of body balance. Considering the inflexibility of postural responses in individuals with Parkinson's disease (PD), maintaining stability in the support base's continuous oscillations may be challenging. Varying the frequency of platform oscillation is an exciting approach to assess the interactions between reactive and anticipatory adjustments. Research question This study aimed to analyze postural responses of individuals with PD on an oscillatory support base across different frequencies. Methods Thirty participants with moderate PD diagnosis (M = 64.47 years, SD = 8.59; Hoehn and Yahr scale 3) and fifteen healthy age-matched controls (M = 65.8 years, SD = 4.2) were tested. Subjects maintained a dynamic balance on a platform oscillating in sinusoidal translations. Four oscillation frequencies were evaluated in different trials that ranged from 0.2 to 0.8 Hz in steps of 0.2 Hz. Results Analysis showed similar performance between PD and healthy participants, with modulation of amplitudes of head displacement, center of pressure, center of mass and feet-head coordination to platform oscillation frequency. Discussion Our findings suggest a preserved ability of individuals with PD to dynamically control body balance on a support base with predictable oscillatory translations.

Objective: Movement assymetry is considered a potential risk factor for musculoskeletal injury in sport. Sports such as volleyball are thought to cause movement assymetries due to specific sporting demands. Further, between limb comparisons are often used for return to sport decisions. Despite this, little information is available regarding the presence of assymetry in volleyball athletes. Therefore the purpose of this investigation was to determine the presence of assymetry in dorsiflexion range of motion (DFROM) and dynamic postural control variables, factors important in return to sport decisions, both the group and individual level in professional male volleyball players. Secondarly, we aimed to better understand the role of DFROM on the Star excursion balance test (SEBT), a measure of dynamic postural control. Method: Thirty-two Professional male volleyball players (age: 24.7±5.53 years, height: 190.6±7.63 cm., weight: 84.5±9.28 kg., BMI: 23.22±1.62 kg/m2) participated in this investigation. All participants reported for a single test session during which DFROM and the SEBT were assessed on both limbs. Results: There was a significant group difference (p

The aim of this study was to assess gait initiation (GI) performance longitudinally across clinical concussion recovery milestones through return to participation (RTP). We recruited 54 collegiate student-athletes, 27 with concussions and 27 matched controls (15 female and 12 male per group). Participants performed five trials of GI at baseline and again at five post-concussion clinical milestones: 1) Acute, the day clinical tests achieved baseline values on the 2) Balance Error Scoring System (BESS), 3) Immediate Post-Concussion Assessment and Cognitive Test ImPACT, 4) Asymptomatic, and 5) RTP Day. GI performance on six outcome measures (anterior/posterior and medial/lateral center of pressure displacements and velocities during the anticipatory postural adjustment [APA] phase and initial step length and velocity) with repeated-measures mixed model and pair-wise post hoc. A reliable change index (RCI) was calculated, and post-concussion participant's performance was compared to the RCI at milestones. There were significant interactions for APA posterior and lateral displacement, APA posterior velocity, step length, and step velocity. The post-hoc tests identified significant deficits across clinical milestones and at RTP for APA posterior and lateral displacement, step length, and step velocity. There were no post-hoc differences for any outcome measure in the control group. At RTP, 85.2-88.9% of concussion participants had at least one outcome measure which exceeded the 80% or 95% RCI. The primary finding of this study was persistent impairments in dynamic postural control, suggesting ongoing neurophysiological impairment despite clinical recovery. These results suggest that collegiate student-athletes may be RTP before neurophysiological recovery and potentially exposing themselves to elevated risk of recurrent concussion or subsequent musculoskeletal injury.

Background: Taekwondo is a technique of unarmed self-defense that involves skillful application of techniques which include punching, jumping, kicks, blocks and dodges. Beside speed, response to the opponent’s actions along with good balance appear to be key elements for victory. Hence a good balance is required for excellent performance with minimal injuries Method: A total of 60 players were selected based on inclusion and exclusion criteria. The aim and objectives of the study were explained to them and their written consent was taken. Balance was assessed using single legged stance test and community balance and mobility scale. The players were divided into two groups of 30 players each. A four week intervention program consisting of dynamic postural control activities was given to the players in group Athrice a week for four consecutive weeks and those in group B received conventional exercises including stretching and drilling. The pre and post values were recorded on 1st and 12th day respectively and the data obtained was statistically analyzed. Results:The average CBM scale score before intervention were 74/96 in group A and 72/96 in group B. These were improved to an average of 91.2/96 and 80.32/96 in group A and group B respectively after intervention showing a value of p

Aims To compare the static and dynamic postural control of people with Parkinson's disease and community old adults. Methods Thirty-five people were in the Parkinson's disease group (PDG; 12 women, 62.4 ± 11.0 years, 77.9 ± 15.6 kg, 166.5 ± 11.0 cm, 27.9 ± 3.8 kg/m2 , 1.9 ± 0.5 Hoehn & Yahr) and 32 were in the old adults group (OAG; 13 women, 69.5 ± 6.0 years, 74.2 ± 12.3 kg, 165.0 ± 8.3 cm, 27.2 ± 4.0 kg/m2 ). The static balance was measured on a force platform, three 30-s trials in four conditions: feet side-by-side (FSBS) and semi-tandem stance (ST) positioning, eyes open (EO) and eyes closed (EC). The total sway path length (SPL), sway area (SA), anterior-posterior (APSR) and medial-lateral (MLSR) sway range of the centre of pressure were obtained. Dynamic balance was assessed using the timed-up-and-go test (TUG). For comparison between groups and repeated-measures, a mixed-design ANOVA was carried out and the Mann-Whitney U test to compare TUG between groups. The significance level was set at p ≤ .05. Results Between groups, PDG presented higher mean values for SPL, APSR and SA in feet side-by-side eyes open compared to the OAG, for SPL in feet side-by-side eyes closed, for SPL and SA in STEO. For repeated-measures, both groups had higher mean values in the EC condition compared to EO and MLSR compared to APSR. No significant difference was found between groups for TUG. Conclusion Balance disorders are found early in people with Parkinson's disease compared to healthy older adults. Thus, Parkinson's disease seems to advance the process of alterations in the postural control system.

PURPOSE: The purpose of this study was to assess the effect of repetitive head impacts experienced by football players compared to non-contact athletes on dynamic postural control during both Single Task (ST) and Dual Task (DT) conditions. METHODS: Thirty four football players wearing accelerometer instrumented helmets and 13 cheerleaders performed a dynamic postural control battery, consisting of ST and DT gait initiation, gait, and gait termination, both prior to and following the football season. A 2 (group) x 2 (time) repeated measures ANOVA compared performance across 32 dynamic postural outcomes. A linear regression was performed on postural control change scores with common head impact kinematics serving as the independent variables. RESULTS: The football players experienced a mean of 538.1 ± 409.1 head impacts in the season with a mean linear acceleration of 27.8 ± 3.2 g’s. There were no significant interactions for any of the ST or DT dynamic postural control tasks. There was a significant relationship between head impact kinematics and the lateral center of pressure displacement during the anticipatory postural adjustment phase (r(2) = 0.26, p=0.010) and transitional phase (r(2) = 0.511, p=0.042) during ST gait initiation. For both measures, the number of impacts exceeding 98 g’s was the only significant predictor of decreased center of pressure displacement. CONCLUSIONS: A single competitive football season did not adversely affect dynamic postural control when comparing football players to cheerleaders who do not experience repetitive head impacts. Furthermore, there were limited relationships with head impact kinematics suggesting that a single season of football does not adversely affect most outcome measures of instrumented dynamic postural control. These findings are consistent with most studies which fail to identify clinical differences related to repetitive head impacts.

Background: Visual impairments are common following concussion, and vision tests are recommended as part of a comprehensive clinical concussion evaluation. Persistent symptoms from vision disturbances can delay recovery and earlier detection may reduce symptom burden. Further, while gait-related deficits were reported among adolescents with abnormal near point of convergence following concussion, further research is needed to understand gait performance among those with impaired eye tracking abilities. Hypothesis/Purpose: Our purposes were to: 1) examine the relationship between self-reported symptoms and concussion-related visual impairments; and 2) compare single-task and dual-task gait speed between concussed adolescents with and without abnormal visual tracking abilities, to healthy controls. Methods: Thirty concussed participants and thirty healthy controls (Table 1) completed an eye tracking assessment during which they watched a brief (220s) video clip. The video clip moved in a clockwise direction around the screen while pupil positions were measured with an objective eye tracker to create a box trajectory of each eye movement. The eye tracking dependent variable (BOX score) was a binary classifier with

Purpose The purpose of this study was to investigate the effects of a functional fatigue protocol on lower extremity dynamic and static postural control. Methods A total of 20 physically active collegiate students participated in this study (ten males, ten females; age 22.5±2.7 years; mass 67.0±13.0 kg; height 168.0±8.9 cm). A unilateral stance with eyes closed for 10 seconds was performed to test static postural control using a balance force plate and single-leg drop landing on 30cm box was performed as a dynamic postural control test and captured using VICON motion analysis system. Results The results of this study showed an average heart rate of 176.3 beats/minute, an 18 rating on the perceived exertion scale, significant differences in blood lactate, and a static postural control deficit after fatigue as compared with before fatigue(p

In Parkour activity, the aim is to move from one place to another as quickly and efficiently as possible by running, climbing, swinging, vaulting, rolling, crawling and jumping on tiny obstacles … . Performing these actions places a great demand on the postural control system. The purpose of the present study was to investigate postural control of Parkour practitioners - called Traceurs - compared to recreationally active (RA) subjects in different postural conditions after manipulating the visual and/or proprioceptive sensory inputs. Ten Traceurs (mean experience 5.9 ± 0.9 years;5 hours per week) and 10 RA subjects participated in this study. We measured the centre of pressure area (CoP

The relationship between falls and static and dynamic postural control has not been established in Parkinson's disease (PD). The purpose was to compare the compensatory postural strategies among fallers and non-fallers with PD as well as older adults during static and dynamic movements.Twenty-five individuals with PD (11 fallers) and 17 older adults were outfitted with 6 accelerometers on the wrists, ankles, lumbar spine, and sternum, stood quietly for 30 s on a force platform, and walked back and forth for 30 s along a 15 m walkway. Root-mean-square displacement amplitude of the center of pressure (COP), COP velocity, gait spatial-temporal characteristics, trunk range of motion (ROM), and peak trunk velocities were obtained.COP velocity in anterior-posterior was larger in older adults than those with PD (p 0.05). Trunk frontal ROM and velocity were smaller in fallers and non-fallers with PD compared to older adults (p 0.05). Trunk anterior-posterior ROM and velocity were smaller in fallers than non-fallers with PD and older adults (p 0.05). In fallers with PD, negative correlations were shown between the sagittal trunk velocity and the COP velocity in the anterior-posterior direction as well as between trunk frontal velocity and COP velocity in both directions (p 0.05). In non-fallers with PD, horizontal trunk ROM and velocity were positively correlated with COP ROM and velocity in the medial-lateral direction (p 0.01).Dynamic postural control revealed better discrimination between groups than static. Fallers and non-fallers with PD and older adults adopted different compensatory strategies during static and dynamic movements; thereby providing important information for falls-risk assessment.

© 2018 IOS Press and the authors. BACKGROUND: The Star Excursion Balance Test (SEBT) is a common clinical test that can provide information about dynamic movement, but does not reflect movement quality or postural-control strategies, and does not report kinematics of the lower limb. PURPOSE: To assess the dynamic postural control of healthy subjects using inertial measurement units (IMUs) and clinical SEBT scores to determine the effect of knee bracing and taping. METHODS: Twenty-four healthy individuals performed the SEBT under three randomised conditions (patellar bracing, patellar taping, and control condition (no intervention). Clinical SEBT scores were recorded and normalised to leg length and angular velocities were measured using IMUs during SEBT. Composite scores were calculated as the sum of clinical scores in each direction divided by three. Descriptive statistics (mean±sd) were calculated for each variable and repeated measures ANOVA were used to identify differences between limb (dominant, non-dominant) and condition. MAIN RESULTS: Compared to the control condition, bracing and taping significantly improved dynamic postural control in the sagittal plane by 6% (1.5-10.5%) P = 0.011 and 8% (2.9-13%) P = 0.004 respectively. Bracing significantly improved coronal plane stability compared to the control condition by 9% (3.8-14.1%) P = 0.002, and taping by 7% (1.6-12.6%) P = 0.013. SEBT scores revealed small but statistically significant differences (P < 0.05) between conditions in the anterior, posteromedial and composite scores, all showing a difference of between 1-2%. PRINCIPAL CONCLUSIONS: Patellar soft bracing and taping can improve dynamic postural stability during SEBT. It is possible to detect clinically important changes in lower limb stability from angular velocity using IMUs.

Study Design Cross-sectional. Background Hip pain is associated with reduced muscle strength and range of movement (ROM). These impairments may contribute to decreased postural stability and balance. The Star Excursion Balance Test (SEBT) is a reliable and valid method to measure dynamic postural control. Objectives To evaluate the association between SEBT performance and hip strength, hip ROM, trunk endurance, and group characteristics in individuals with hip pain. Methods One hundred eleven individuals with hip pain, scheduled for arthroscopic hip surgery, were matched with 62 healthy controls. Hip ROM and muscle strength, trunk endurance, and SEBT reach were measured prior to surgery. Data were analyzed for between-group differences using t tests, and associations between SEBT reach and hip strength, hip ROM, and population characteristics were evaluated with Pearson correlation coefficients and stepwise backward regression analyses. Results Star Excursion Balance Test performance (P.01), hip strength (P.01), and hip ROM (P.05) were lower in the presurgery group compared to controls. In the presurgery group, when adjusted for height and weight, hip flexion strength and internal rotation ROM accounted for 44% of the variance in anteromedial SEBT reach. In the posteromedial direction, hip adduction strength and sex accounted for 53% of the variance. For the posterolateral direction, hip adduction and internal rotation strength accounted for 46% of reach variance. Conclusion The individuals who were scheduled for arthroscopic hip surgery were significantly weaker, had less hip mobility, and had reduced dynamic balance compared to controls. In this population, dynamic balance performance was associated with various hip strength and ROM measurements in a direction-specific manner. J Orthop Sports Phys Ther 2018;48(4):280-288. doi:10.2519/jospt.2018.7946.

Considering the high recurrent injury rates, athletes may receive clearance for return-to-play (RTP) from a lateral ankle sprain (LAS) before impairments and activity limitations are resolved. The purpose of this study was to examine residual structural and functional impairments and activity limitations at RTP in athletes with a LAS. We found that athletes demonstrated increased ankle ligamentous laxity and reduced self-reported function, dorsiflexion ROM, and dynamic postural control at RTP. Athletes with a LAS likely require more extensive care to resolve impairments and activity limitation before RTP.

Digital games controlled by body movements (exergames) have been proposed as a way to improve postural control among older adults. Exergames are meant to be played at home in an unsupervised way. However, only few studies have investigated the effect of unsupervised home-exergaming on postural control. Moreover, suitable methods to dynamically assess postural control during exergaming are still scarce. Dynamic postural control (DPC) assessment could be used to provide both meaningful feedback and automatic adjustment of exergame difficulty. These features could potentially foster unsupervised exergaming at home and improve the effectiveness of exergames as tools to improve balance control. The main aim of this study is to investigate the effect of six weeks of unsupervised home-exergaming on DPC as assessed by a recently developed probabilistic model. High probability values suggest ‘deteriorated’ postural control, whereas low probability values suggest ‘good’ postural control. In a pilot study, ten healthy older adults (average 77.9, SD 7.2 years) played an ice-skating exergame at home half an hour per day, three times a week during six weeks. The intervention effect on DPC was assessed using exergaming trials recorded by Kinect at baseline and every other week. Visualization of the results suggests that the probabilistic model is suitable for real-time DPC assessment. Moreover, linear mixed model analysis and parametric bootstrapping suggest a significant intervention effect on DPC. In conclusion, these results suggest that unsupervised exergaming for improving DPC among older adults is indeed feasible and that probabilistic models could be a new approach to assess DPC.

Background: The Functional Movement Screen (FMS) is used to evaluate key movement patterns, functional symmetry, and identify individuals that are at elevated risk of injury. The purpose of this study was to assess whether dynamic postural control is a significant component of the composite FMS score by comparing it with Y-Balance Test (YBT) reach distances. Methods: Seventy-eight participants (including 40 males) performed the standardized FMS protocol followed by the YBT. The YBT reach distances were normalized to leg length and averaged between sides and trials. The individual reach directions were evaluated, and were also summed to form an aggregate YBT distance (TotalY). Results: We observed weak correlations between the composite FMS score and normalized posterolateral reach, normalized posteromedial reach, and the TotalY (r=0.36, 0.37, and 0.36, respectively; all p< 0.05). There was no correlation between the composite FMS score and normalized anterior reach (r=0.22; p=0.053). Together these findings demonstrate partial correspondence between the two tests. Conclusion: This indicates that dynamic postural control is a small component of the aggregate FMS score.

Background Agonist and antagonist muscle co-contractions during motor tasks are greater in the elderly than in young adults. During normal walking, muscle co-contraction increases with gait speed in young adults, but not in elderly adults. However, no study has compared the effects of speed on muscle co-contraction of the ankle joint during dynamic postural control in young and elderly adults. We compared muscle co-contractions of the ankle joint between young and elderly subjects during a functional stability boundary test at different speeds. Methods Fifteen young adults and 16 community-dwelling elderly adults participated in this study. The task was functional stability boundary tests at different speeds (preferred and fast). Electromyographic evaluations of the tibialis anterior and soleus were recorded. The muscle co-contraction was evaluated using the co-contraction index (CI). Results There were no statistically significant differences in the postural sway parameters between the two age groups. Elderly subjects showed larger CI in both speed conditions than did the young subjects. CI was higher in the fast speed condition than in the preferred speed condition in the young subjects, but there was no difference in the elderly subjects. Moreover, after dividing the analytical range into phases (acceleration and deceleration phases), the CI was larger in the deceleration phase than in the acceleration phase in both groups, except for the young subjects in the fast speed conditions. Conclusions Our results showed a greater muscle co-contraction of the ankle joint during dynamic postural control in elderly subjects than in young subjects not only in the preferred speed condition but also in the fast speed condition. In addition, the young subjects showed increased muscle co-contraction in the fast speed condition compared with that in the preferred speed condition; however, the elderly subjects showed no significant difference in muscle co-contraction between the two speed conditions. This indicates that fast movements cause different influences on dynamic postural control in elderly people, particularly from the point of view of muscle activation. These findings highlight the differences in the speed effects on muscle co-contraction of the ankle joint during dynamic postural control between the two age groups.

Background: Surfing is a high skill sport that requires a considerable amount of time in a variety of ocean conditions to help develop the fundamental techniques. Objective: The purpose of this study was to investigate the effect of four weeks of detraining on strength, power, and sensorimotor ability in adolescent surfers. Methods: Nineteen adolescent surfers (13.8 A 1.7 y, 53.6 A 10.8 kg and 165.1 A 8.9 cm) participated in four weeks of detraining (surfing participation maintained but resistance training ceased) following seven weeks of periodized resistance training. Maximal isometric strength, power, and sensorimotor ability pre-test results were determined from the conclusion (post-test) of the first seven-week training block while post-test results were measured at the start (pre-test) of a second seven-week training block. Results: Four weeks of detraining significantly decreased the following variables: Vertical jump height by -5.26%, (p=0.037, d= 0.40), vertical jump peak velocity by -3.73% (p=0.001, d= 0.51), isometric strength by -5.5%, (p=0.012, d= 0.22), and relative isometric strength by -7.27% (p=0.003, d= 0.47). Furthermore, sensorimotor ability worsened, with a significant increase of 61.36% (p=0.004, d= 1.01), indicating that athletes took longer to stabilize from a dynamic landing task. Conclusions: This demonstrates that surfing, in the absence of resistance training, is not a sufficient training stimulus to maintain physical characteristics. Adolescent surfers with a relatively low training age should avoid cessation of resistance training and strive to maintain consistent resistance training in conjunction with surf training in order to avoid negative decrements in physical characteristics that are associated with surfing performance.

Ankle ligaments injury is a common trauma in athletes, when proprioception, sensomotor control, muscle strength and balance are disturbed. Possibility to have trauma remains high, thus, trauma prevention plays a very important role. The aim of the study was to evaluate dynamic postural control and possibility to have ankle injury before and after spine stability exercise. Basketball players’ dynamic postural control was assessed using the modified Star Excursion Balance test and risk to experience ankle trauma – the calculation of the combined result. Before applying spine stability exercise basketball players who had not had degree II ankle sprain had better dynamic postural control in all directions than basketball players who had had degree II ankle sprain. After eight weeks of applying spine stability exercise dynamic postural control of basketball players who had had degree II ankle sprain improved significantly (p < 0.05) in all directions, dynamic postural control of but basketball players who not had degree II ankle sprain improved, but insignificantly (p > 0.05). Before applying spine stability exercise, 78% of basketball players who had had degree II ankle sprain and 22% basketball players who not had degree II ankle sprain had higher possibility to experience ankle trauma, but after eight weeks of spine stability exercise 11% of basketball players in both groups had higher possibility to experience ankle trauma. Spine stability exercise had positive effect on dynamic postural control and reduced possibility to experience ankle injury.Keywords: dynamic postural control, ankle injury, spine stability, modified Star Excursion Balance test.

The aim of the study was to assess the effects of multidirectional plyometric training (MPT) on vertical jump height, change of direction performance (CODP), and dynamic postural control (DPC) in young soccer players. Twenty-eight young male soccer players were randomly assigned to an experimental group (EG, n = 14; age: 11.8 ± 0.4 years) and a control group (CG, n = 14; age: 11.6 ± 0.5 years). The EG introduced 8-week MPT, two days per week into their in-season training, while CG continued training without change. Measurements of vertical jump height, CODP, and DPC were completed at the beginning and end of the 8-week MPT. A significant group × time interaction was observed for Squat-Jump (p < 0.05), for Counter-Movement Jump (p < 0.05), and for CODP test (p < 0.05). In addition, a significant group × time interaction was observed for DPC in seven axes for the dominant- (anterior, lateral, postero-lateral, posterior, postero-medial, medial, and antero-medial; p < 0.05 for all) and in seven axes for the non-dominant- (anterior, antero-lateral, lateral, posterior, postero-medial, medial and antero-medial; p < 0.05 for all) legs. The rest of the axes of both legs did not show any significant group × time interaction (p > 0.05). In conclusion, incorporating MPT into the in-season regimen of young male soccer players improved performance of various indices related to soccer activity (i.e., vertical jump height, CODP, and DPC). MPT has the potential to be appealing to coaches, as it requires little time while yielding valuable results in the physical preparation of young soccer players.

Context: The Y-Balance Test (YBT) and Star Excursion Balance Test (SEBT) are commonly used to detect deficits in dynamic postural control. There is a lack of literature on the differences in reach distances and efficiency of the tests. Objective: To compare the reach distances of the YBT and SEBT. An additional aim was to compare the time necessary to administer the 2 tests and utilize a discrete event simulation to determine the number of participants who could be screened within different scenarios. Design: Cross-sectional. Laboratory Patients: Twenty-four physically active individuals between the ages of 18–35 years volunteered to participate in this study (M/F: 11/13; age 22.78 [2.63] y, height 68.22 [4.32] cm, mass 173.27 [10.96] kg). Intervention: The participants reported to the laboratory on one occasion and performed the YBT and SEBT. The anterior, posteromedial, and posterolateral reach distances were recorded for each test. In addition, the time to administer each test was recorded in seconds. Main Outcome Measures: The average reach distances and time for each test were used for analysis. Paired t tests were utilized to compare the reach distances and time to administer the 2 tests. A discrete event simulation was used to determine how many participants could be screened using each test. Results: The anterior reach for the SEBT (64.52% [6.07%]) was significantly greater than the YBT (61.66% [6.37%]; P P Conclusion: Scores on the anterior reach of the SEBT are larger when compared with the YBT. The discrete event simulation can successfully be used to determine how many participants could be screened with a certain amount of resources given the use of a specific test.

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−1increase 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.

Objective To conduct a systematic review with meta-analysis assessing the effectiveness of joint mobilizations for improving dorsiflexion range of motion (DFROM) and dynamic postural control in individuals with chronic ankle instability. Data Sources Electronic databases (PubMed, MEDLINE, CINAHL, and SPORTDiscus) were searched from inception to January 2017. Study Selection Included studies examined the isolated effects of joint mobilizations to enhance DFROM and dynamic postural control in individuals with chronic ankle instability and provided adequate data to calculate effect sizes (ESs) and 95% confidence intervals (CIs). Data Extraction Two investigators independently assessed the methodologic quality, level of evidence, and strength of recommendation using the Physiotherapy Evidence Database scale and the Strength of Recommendation Taxonomy. We extracted the sample sizes, means, and standard deviations for DFROM and dynamic postural control and filtered the data based on control-to-intervention and preintervention-to-postintervention (pre-post) comparisons. Data Synthesis We included 7 level 1 and 3 level 2 studies that had a median Physiotherapy Evidence Database score of 60% (range = 40%–80%). The magnitudes of control-to-intervention and pre-post differences were examined using bias-corrected Hedges g ESs. Random-effects meta-analyses were conducted for each outcome measure and comparison. Positive ESs indicated better outcome scores in the intervention group than in the control group and at postintervention than at preintervention. The α level was set at .05. Meta-analysis revealed weak and moderate ESs for overall control-to-intervention (ES = 0.41; 95% CI = 0.14, 0.68; P = .003) and pre-post (ES = 0.34; 95% CI = 0.20, 0.48; P < .001) DFROM analyses. Overall, dynamic postural control meta-analysis revealed moderate control-to-intervention (ES = 0.42; 95% CI = −0.14, 0.98; P = .14) and weak and moderate ESs for pre-post (ES = 0.37; 95% CI = −0.12, 0.87; P = .14) analyses. Conclusions We observed grade A evidence that joint mobilizations can mildly improve DFROM among individuals with chronic ankle instability compared with controls and preintervention. We observed grade B evidence that indicated conflicting effects of joint mobilizations on dynamic postural control compared with controls and preintervention.

Introduction: Muscular fatigue is a common phenomenon in daily sports activities and is worsening motor performance. The aim of this study was to determine the effect of neck muscular fatigue on static and dynamic postural control in elite male volleyball players. Correspondence: Maryam Mazidi, MSc. Department of Sport Injuries & Corrective Exercises, Hormozgan University. Bandar Abbas, Iran Tel:+98 09381787230 Email: m.mazidi100@gmail.com Methods: For this study, 30 elite male athletes with mean age of 23.3p3.5 years old, height of 184.1p7.7 cm, and weight of 76.6p3.1 kg were selected in the available form and divided randomly into control and experimental groups. Fatigue protocol was induced on both sides via maximal exhausting protocol by instructing the subjects in experimental group to perform a lDumbbell Shrug Trap Exerciser commonly used in fitness training to specifically involve Levator Scapulae and Trapezius superior muscles. The subjectsr dynamic and static postural control immediately after fatigue were assessed by Biodex System (level 4 and 3). For statistical analysis paired and sample t-test (al0.05) were used. Results: The results of this study showed that in the level 4 of Biodex system there were significant differences in Ant-Post (P=0.030), Med-Lat (P=0.020), Limit of stability (P=0.012) and dynamic balance (P=0.011). In the level 8 of Biodex system there were significant differences in Ant-Post (P=0.022), Med-Lat (P=0.020), Limit of stability (P=0.011) and dynamic balance (P=0.021). With respect to study results, there were significant differences in static balance(P=0.012) in experimental group but there were not significant differences in control group (P=0.214). Conclusion: Based on this study results, we concluded that neck muscle fatigue affects stability indexes, static and dynamic postural control so it seems that increasing the endurance of neck muscles to prevent early time fatigue, should be considered.

Baghbani, F, Woodhouse, LJ, and Gaeini, AA. Dynamic postural control in female athletes and nonathletes after a whole-body fatigue protocol. J Strength Cond Res 30(7): 1942-1947, 2016-Postural control is a crucial element in regular training of athletes, development of complex technical movement, and injury prevention; however, distributing factor of the postural control such as fatigue has been neglected by athletic trainers in novice and inexperienced athletes. The objective of this study was to compare changes in dynamic postural control of young female athletes and nonathletes after a fatigue protocol. Thirty females (15 athletes and 15 nonathletes) with no orthopedic problems were recruited to participate in this study. All participants completed the pre-SEBT (star excursion balance test) in 8 directions at baseline; then, they performed a 20-minute fatigue protocol after which post-SEBT was measured. Rating of perceived exertion was measured using the Borg scale immediately before, mid-way through (i.e., after the third station), and after performing the fatigue protocol (i.e., immediately before the post-SEBT). Female nonathlete groups had significant differences in dynamic balance performance after fatigue in the medial, posteromedial, and posterior directions (p < 0.01) measured by SEBT. Athletes, however, showed no significant changes after the fatigue protocol. Our results indicates the importance of evaluation and monitoring of dynamic postural control of the novice with progressing the exercise time. Our findings could also help coaches to develop trainings focused on the 3 directions of medial, posteromedial, and posterior directions and aimed at exercises increasing fatigue resistance.

Purpose: Postural control preserves organs and body parts in a proper biomechanical stance which exists in two forms: static and dynamic. Fatigue is one of the factors that affects postural control. This study aimed to compare the electromyography (EMG) activity of the lower extremity muscles before and after fatigue. Methods: This study was descriptive correlational and based on the research type a field study. Study sample comprised 20 male students majored in physical education; they were purposefully selected by non-accidental all-accounted method. Surface EMG activities of lower extremity muscles before and after fatigue were evaluated by electromyogram. To create fatigue in lower extremity muscles, we used fatigue protocol by the Biodex system. Data analysis was carried out by using SPSS 21. The paired t test was used for statistical analysis with a significance level of P