Single-limb Stance Research Articles

The effect of simulated elbow contracture on temporal and distance gait parameters

BackgroundElbow contractures can be functionally debilitating. Extensive research has been published on treatments to restore elbow motion, but few have discussed clinical implications beyond the affected extremity. Reciprocal arm swing in normal gait has been shown to increase stability and reduce energy expenditure. The importance of arm swing has been clinically demonstrated in patients with cerebral palsy, stroke and Parkinson's disease. We hypothesized that elbow contractures would result in an abnormal spatio-temporal gait parameters. MethodsForty volunteer subjects walked on the Gaitmat II which provided real-time analysis of temporal and distance gait parameters. Five conditions were tested: no brace (control 1), elbow brace unlocked (control 2) and brace locked in 30°, 90° or 120° flexion (simulating fixed elbow contractures). Condition order was randomized for each subject. Each condition consisted of five walking trials. ResultsAll three fixed elbow conditions (120°, 90° and 30°) demonstrated significantly decreased gait velocity (1.37, 1.39 and 1.39m/s) and stride length (1.45, 1.46 and 1.46m) compared to the control condition (1.42m/s and 1.48m, respectively). Single limb stance and double support times were decreased and increased, respectively, compared to control. There was no significant difference in cadence or limb asymmetry in the three fixed elbow conditions. ConclusionsDespite well-established functional limitations in elbow contracture patients and importance of arm swing in normal gait, the impact of elbow contractures on gait is unknown. This study demonstrates that simulated elbow contracture results in significant differences in spatio-temporal gait parameters suggesting that elbow contractures have a broader functional impact beyond the affected extremity. Level of evidenceII.

Postural sway in single-limb and bilateral quiet standing after unilateral total knee arthroplasty

AimTo investigate whether total knee arthroplasty (TKA) was associated with stability in single-limb stance and whether reduced stability in single-limb stance was associated with increased postural sway in bilateral quiet standing. Methods3D kinematics for center of mass was used to assess postural sway in 23 subjects with TKA and 23 controls. Tests included bilateral quiet standing with and without vision and on a compliant surface, and single-limb stance. Results30% of the subjects in the TKA group were unable to maintain single-limb stance for 20s on any leg. Of the 70% in the TKA group able to stand on one leg, mean sway velocity in the medio-lateral direction was marginally higher for the prosthetic side (p=.02), but no differences were found between the TKA and the control group in single-limb stance. Performance in bilateral quiet standing was similar in TKA-subjects, able as well as unable to stand on one leg, and controls. Reduced quadriceps strength in the contralateral leg, higher BMI, and older age predicted failure to maintain single-limb stance. ConclusionIn subjects able to stand on one leg, performance was considered comparable between the prosthetic and contralateral side and between groups. Inability to stand on one leg did not affect postural sway in bilateral quiet standing. The results suggest that inability to maintain single-limb stance is explained by reduced physical capacity rather than the knee condition in itself. The present study emphasizes the importance of physical activity to improve strength and functional capacity.

Trunk–pelvis motion, joint loads, and muscle forces during walking with a transtibial amputation

People with unilateral, transtibial amputation (TTA) have an increased prevalence of chronic low back pain (LBP) relative to able-bodied people. However, a definitive cause of increased LBP susceptibility has not been determined. The purpose of this work was to compare dynamic trunk–pelvis biomechanics between people with (n=6) and without (n=6) unilateral TTA during walking using a computational modeling approach. A generic, muscle-actuated whole body model was scaled to each participant, and experimental walking data were used in a static optimization framework to calculate trunk–pelvis motion, L4L5 joint contact forces, and muscle forces within the trunk–pelvis region. Results included several significant between-group differences in trunk–pelvis biomechanics during different phases of the gait cycle. Most significant was greater lateral bending toward the residual side during residual single-limb stance (p<0.01), concurrent with an elevated L4L5 joint contact force (p=0.02) and greater muscle force from the intact-side obliques (p<0.01) in people with TTA relative to able-bodied people. During both double-limb support phases, people with TTA also had a greater range of axial trunk rotation away from the leading limb, concurrent with greater ranges of muscle forces in the erector spinae and obliques. In addition, a greater range of force (p=0.03) in residual-side psoas was found during early residual limb swing in people with TTA. Repeated exposure to atypical motion and joint/muscle loading in people with TTA may contribute to the development of secondary musculoskeletal disorders, including chronic, mechanical LBP.

CSM 2015 Sports Physical Therapy Section Platform Presentations (Abstracts SPL1–SPL67)

CSM 2015 Sports Physical Therapy Section Platform Presentations (Abstracts SPL1–SPL67)

Effects of auditory feedback during gait training on hemiplegic patients' weight bearing and dynamic balance ability.

[Purpose] This study examined the effects of auditory feedback during gait on the weight bearing of patients with hemiplegia resulting from a stroke. [Subjects] Thirty hemiplegic patients participated in this experiment and they were randomly allocated to an experimental group and a control group. [Methods] Both groups received neuro-developmental treatment for four weeks and the experimental group additionally received auditory feedback during gait training. In order to examine auditory feedback effects on weight bearing during gait, a motion analysis system GAITRite was used to measure the duration of the stance phase and single limb stance phase of the subjects. [Results] The experimental group showed statistically significant improvements in the duration of the stance phase and single limb stance phase of the paretic side and the results of the Timed Up and Go Test after the training. [Conclusion] Auditory feedback during gait training significantly improved the duration of the stance phase and single limb stance phase of hemiplegic stroke patients.

The correlation between postural control and upper limb position sense in people with chronic ankle instability.

BackgroundChronic ankle instability (CAI) is attributed to functional instability driven by insufficient proprioception. However, it is not clear whether the deficits are related to global impaired performance or to specific decrease in ankle motor-control. The aim of this study was to assess the correlation between lower limb postural control and upper limb position sense among people with CAI, in order to further explore the function of the central neural control in people with CAI.MethodsFourteen participants (10 males, 4 females) with self-reported CAI and 14 age- and gender-matched, healthy controls participated in this study. Each participant completed single-limb stance postural control tests and shoulder position sense tests. The Overall Stability Index (OSI) was used as a measure of postural stability. The average of the absolute error score (AES) was calculated as a measure of shoulder position sense. Pearson correlations between the scores of the four body sites –lower limb postural stability (preferred/non-preferred), shoulder (preferred/non-preferred) were determined separately for each group.ResultsIn the control group, significant correlations were found between the OSI score of the right and left ankles (r = 0.887, p < 0.001), between the AES of the right and left shoulders (r = 0.656, p = 0.011), as well as between the OSI score and the AES of the non-preferred side (r = 0.649, p = 0.012). In the CAI group, significant correlation was found only between the OSI score at both ankles (r = 0.6, p = 0.002).ConclusionsIndividuals with CAI demonstrated lower limb postural control and upper limb position sense similar to those shown in healthy controls. However, correlations between the lower and upper limbs were observed only in the healthy controls. Clinicians can use this information and employ activities that focus on coordinating the upper and lower extremities when designing neuromuscular control training programs for people with CAI.

Body Weight–Supported Treadmill Training Is No Better Than Overground Training for Individuals with Chronic Stroke: A Randomized Controlled Trial

Background: Body weight-supported treadmill training (BWSTT) has produced mixed results compared with other therapeutic techniques. Objective: The purpose of this study was to determine whether an intensive intervention (intensive mobility training) including BWSTT provides superior gait, balance, and mobility outcomes compared with a similar intervention with overground gait training in place of BWSTT. Methods: Forty-three individuals with chronic stroke (mean [SD] age, 61.5 [13.5] years; mean [SD] time since stroke, 3.3 [3.8] years), were randomized to a treatment (BWSTT, n = 23) or control (overground gait training, n = 20) group. Treatment consisted of 1 hour of gait training; 1 hour of balance activities; and 1 hour of strength, range of motion, and coordination for 10 consecutive weekdays (30 hours). Assessments (step length differential, self-selected and fast walking speed, 6-minute walk test, Berg Balance Scale [BBS], Dynamic Gait Index [DGI], Activities-specific Balance Confidence [ABC] scale, single limb stance, Timed Up and Go [TUG], Fugl-Meyer [FM], and perceived recovery [PR]) were conducted before, immediately after, and 3 months after intervention. Results: No significant differences (α = 0.05) were found between groups after training or at follow-up; therefore, groups were combined for remaining analyses. Significant differences (α = 0.05) were found pretest to posttest for fast walking speed, BBS, DGI, ABC, TUG, FM, and PR. DGI, ABC, TUG, and PR results remained significant at follow-up. Effect sizes were small to moderate in the direction of improvement. Conclusions: Future studies should investigate the effectiveness of intensive interventions of durations greater than 10 days for improving gait, balance, and mobility in individuals with chronic stroke.

Characterization of Static Balance Abilities in Elite Soccer Players by Playing Position and Age

In this study, we investigated the static balance of adult and adolescent elite soccer players to understand how expertise and playing position influence postural control. Seventy-one national level players were tested using a force platform to acquire Center-of-Pressure (COP) data in uni- and bipedal stance and calculate sway area (SA), COP path length, velocity and displacements. The results show significant differences in postural sway related to age and playing position only for single-limb stance. In particular, midfielders exhibited significantly lower values of SA with respect to defenders (–48%, p = 0.001) and the under-15 players exhibited SA 42–64% higher than all the others (p = 0.001). In the light of planning training or rehabilitation programs specific for each player’s role and age, sway measurements may supply useful, objective and reliable information only for the unipedal test as the bipedal standing appears not challenging enough to let differences in balance abilities emerge.

Does a Single Session of High-Intensity Interval Training Provoke a Transient Elevated Risk of Falling in Seniors and Adults?

Background: Balance and strength training can reduce seniors' fall risk up to 50%. Available evidence suggests that acute bouts of neuromuscular and endurance exercise deteriorate postural control. High-intensity endurance training has been successfully applied in different populations. Thus, it seemed valuable to examine the acute effects of high-intensity interval training (HIIT) on neuromuscular performance in seniors and young adults. Objective: The acute impact of a HIIT session on balance performance and muscle activity after exercise cessation and during post-exercise recovery was examined in young and old adults. We intended to investigate whether a transient exercise-induced fall-risk may occur in both groups. Methods: 20 healthy seniors (age 70 (SD 4) years) and young adults (age 27 (SD 3) years) were examined on 3 days. After exhaustive ramp-like treadmill testing in order to determine maximal heart rate (HR_max) on the first day, either a 4 × 4 min HIIT at 90% of HR_max or a control condition (CON) was randomly performed on the second and third day, respectively. Balance performance (postural sway) was assessed during single limb stance with open eyes (SLEO) and double limb stance with closed eyes (DLEC). EMG was recorded for the soleus (SOL), anterior tibialis (TIB), gastrocnemius (GM) and peroneus longus (PL) muscles at the dominant leg. All measures were collected before, immediately as well as 10, 30 and 45 min after HIIT and CON, respectively. Results: Compared to CON, HIIT induced significant increases of postural sway immediately after exercise cessation during SLEO in both groups (adults: p < 0.001, Δ = +25% sway; seniors: p = 0.007, Δ = +15% sway). Increased sway during DLEC was only found for seniors immediately and 10 min after HIIT (post: p = 0.003, Δ = +14% sway, 10 min post: p = 0.004, Δ = +18% sway). Muscle activity was increased during SLEO for TIB until 10 min post in seniors (0.008 < p < 0.03) and immediately after HIIT in adults (p < 0.001). Conclusion: HIIT training may cause an acute ‘open-fall-window' with a transient impairment of balance performance for at least 10 min after exercise cessation in both groups. Occluded vision in seniors seems to prolong this period up to 30 min. Thus, the advantage of HIIT with regard to time efficiency seems debatable when considering transient HIIT-induced impairments of neuromuscular function.

The Effect of Trial Duration on Single-Limb Stance Postural Control Measures

Context:Currently, there are limited guidelines for the trial duration of quiet single-limb postural control tests. However, trial duration may influence the results of postural control assessments.Objective:To examine the effect of trial duration on instrumented measures of postural control in healthy adults.Design:Cross-sectional.Setting:Laboratory.Patients or Other Participants:Ten healthy adults (eight females, two males; age = 22.1 ± 1.5 years; 167.4 ± 9.3 cm; 67.4 ± 12.3 kg).Interventions:Static postural control was assessed using quiet single-limb stance on a force plate. With eyes open and closed, participants stood barefoot on one limb. Instructions were stand with hands on hips and remain as motionless as possible. A practice trial was performed before the collection of three 10 s trials on each limb for each visual condition. The data collected during each trial were analyzed as the initial 2.5 s, the initial 5 s, and 10 s.Main outcome Measures:The independent variables included vision, limb, and trial duration. The dependent variables included postural control examined using time-to-boundary (TTB) variables: mean of TTB minima (TTB-M) and the standard deviation of TTB minima (TTB-SD) in the anterior-posterior (AP) and medial-lateral (ML) directions.Results:No significant 3-way or 2-way interactions or limb main effects were identified. Main effects were identified for vision and trial duration in all TTB variables. Post hoc analysis revealed significant differences between all trial durations in all TTB variables.conclusions:Greater TTB values were exhibited during the 10 s trial durations compared with 5 s and 2.5 s, and 5 s trial durations compared with 2.5 s, indicating postural control improved with longer trial durations. This suggests differing aspects of postural control may be examined with different trial durations.

내리막 보행시 발 전족부 부착형 아웃솔의 각도 변화가 척추기립근과 하지근의 근활성도에 미치는 영향

The purpose of this study was to evaluate the effect of angle change of forefoot`s adhesive outsole on the electromyographic activity (EMG) of the erector spinae and selected lower limbs muscle during downhill walking over ramp. Thirteen male university students (age: yrs, height: cm, weight: N) who have no musculoskeletal disorder were recruited as the subjects. To assess the myoelectric activities of selected muscles, six of surface EMG electrodes with on-site pre-amplification circuitry were attached to erector spinae (ES), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), lateral gastrocnemius (LG), and medial gastrocnemius (MG). To obtain maximum EMG levels of the selected muscles for normalization, five maximum effort isometric contraction were performed before the experimental trials. Each subject walked over and ramp with three different forefeet`s EVA outsole (0, 10, ) in random order at a speed of m/s. For each trial being analyzed, five critical instants and four phases were identified from the recording. The results of this study showed that the average muscle activities of MG and LG decreased in shoes compared to and ones in the initial double limb stance (IDLS). In initial single limb stance (ISLS) phase, the average muscle activities of ES increased with the angle of forefoot`s adhesive outsole, indicating that the increment of shoes` angle induce upper body to flex anteriorly in order to maintain balance of trunk. In terminal double limb stance (TDLS) phase, average muscle activities of TA significantly increased in outsole compared to and ones. There was no external forces acting on the right foot other than the gravity during terminal single limb stance (TSLS) phase, all muscles maintained moderate levels of activity.

Reproducibility of and sex differences in common orthopaedic ankle and foot tests in runners.

BackgroundFor future etiologic cohort studies in runners it is important to identify whether (hyper)pronation of the foot, decreased ankle joint dorsiflexion (AJD) and the degree of the extension of the first Metatarsophalangeal joint (MTP1) are risk factors for running injuries and to determine possible sex differences.These parameters are frequently determined with the navicular drop test (NDT) Stance and Single Limb-Stance, the Ankle Joint Dorsiflexion-test, and the extension MTP1-test in a healthy population. The aim of this clinimetric study was to determine the reproducibility of these three orthopaedic tests in runners, using minimal equipment in order to make them applicable in large cohort studies. Furthermore, we aimed to determine possible sex differences of these tests.MethodsThe three orthopaedic tests were administered by two sports physiotherapists in a group of 42 (22 male and 20 female) recreational runners. The intra-class correlation (ICC) for interrater and intrarater reliability and the standard error of measurement (SEM) were calculated. Bland and Altman plots were used to determine the 95% limits of agreements (LOAs). Furthermore, the difference between female and male runners was determined.ResultsThe ICC’s of the NDT were in the range of 0.37 to 0.45, with a SEM in the range of 2.5 to 5 mm. The AJD-test had an ICC of 0.88 and 0.86 (SEM 2.4° and 8.7°), with a 95% LOA of -6.0° to 6.3° and -5.3° to 7.9°, and the MTP1-test had an ICC of 0.42 and 0.62 (SEM 34.4° and 9.9°), with a 95% LOA of -30.9° to 20.7° and -20° to 17.8° for the interrater and intrarater reproducibility, respectively.Females had a significantly (p < 0.05) lower navicular drop score and higher range of motion in extension of the MTP1, but no sex differences were found for ankle dorsiflexion (p ≥ 0.05).ConclusionThe reproducibility for the AJD test in runners is good, whereas that of the NDT and extension MTP1 was moderate or low. We found a difference in NDT and MTP1 mobility between female and male runners, however this needs to be established in a larger study with more reliable test procedures.

Effects of Age and Gender on Dynamic Stability During Stair Descent

ObjectiveTo determine the effects of age and sex and their interaction effects on dynamic postural stability during stair descent. DesignCross sectional. SettingLaboratory. ParticipantsHealthy younger adults (N=28) and healthy older adults (N=21). InterventionsNot applicable. Main Outcome MeasuresSpatiotemporal gait parameters, displacement of center of mass (COM), instantaneous velocity of the COM, divergence between vertical projection of the COM, and center of pressure (COP). ResultsInteraction effects of age and sex were found in stride duration, COM displacement, and instantaneous velocity of the COM in the mediolateral direction. Older adults demonstrated longer stride duration with shorter double-limb stance and longer single-limb stance during stair descent. Women have significantly longer stride duration than men. The effects of sex and age were significant in the data normalized by height. Older adults and women demonstrated larger peak-to-peak COM displacement, peak instantaneous velocity of the COM, and COM-COP divergence than the younger individuals and men, respectively. Peak instantaneous velocity of the COM was significant different in most pairwise comparisons, but the COM-COP divergence was significantly different in several comparisons. ConclusionsThis study examined the COM and COP parameters to quantify dynamic stability during stair descent across sex and age. Although older women descended stairs successfully, they demonstrated differences in control of instantaneous velocity of the COM compared with the other participants. Dynamic instability could be detected by examining the control of instantaneous velocity of the COM. In developing a better understanding of the balance control of stair descent in healthy older adults, aging patients with various pathologies can be better assessed, appropriately treated, and provided with proper assistive devices.

Quantification and reliability of center of pressure movement during balance tasks of varying difficulty

Postural control is often assessed by quantifying the magnitude of the center of pressure (COP) movement. However, these measures usually focus on the gross amount of movement and ignore the temporal structure of the COP signal. A novel non-linear analysis technique was recently developed to characterize the temporal structure of the COP signal with an output termed the entropic half-life [E(1/2)]. The E(1/2) reflects how much of the previous postural position is used to determine the current postural control strategy (memory effect). The purpose of this study was to quantify the E(1/2) and four COP movement magnitude measurements (medio-lateral and anterior–posterior excursion, path length, 95% ellipse area) for balance tasks increasing in sensory difficulty, as well as the test–retest reliability of each measure. Twenty-seven healthy young adults completed single limb stance tasks varying in sensory difficulty (rigid surface eyes open, rigid surface eyes closed, foam surface eyes open) on two separate occasions. Relative reliability was assessed using an intraclass correlation coefficient (ICC3,3). Absolute reliability was assessed using the standard error of the measurement (SEM) and the sensitivity of the measurement to true changes was assessed using the minimal detectable change (MDC95). The E(1/2) was found to have excellent reliability for all tasks tested (ICC range 0.82–0.91, SEM range 3.5–14.1mm, MCD95 range 9.7–39.2mm). The high reliability of the E(1/2) was comparable to that of movement magnitude measurements. This may be used in order to better understand the underlying motor control system.

Postural control strategies during single limb stance following acute lateral ankle sprain

BackgroundSingle-limb stance is maintained via the integration of visual, vestibular and somatosensory afferents. Musculoskeletal injury challenges the somatosensory system to reweight distorted sensory afferents. This investigation supplements kinetic analysis of eyes-open and eyes-closed single-limb stance tasks with a kinematic profile of lower limb postural orientation in an acute lateral ankle sprain group to assess the adaptive capacity of the sensorimotor system to injury. MethodsSixty-six participants with first-time acute lateral ankle sprain completed a 20second eyes-open single-limb stance task on their injured and non-injured limbs (task 1). Twenty-three of these participants successfully completed the same 20second single-limb stance task with their eyes closed (task 2). A non-injured control group of 19 participants completed task 1, with 16 completing task 2. 3-dimensional kinematics of the hip, knee and ankle joints, as well as associated fractal dimension of the center-of-pressure path were determined for each limb during these tasks. FindingsBetween trial analyses revealed significant differences in stance limb kinematics and fractal dimension of the center-of-pressure path for task 2 only. The control group bilaterally assumed a position of greater hip flexion compared to injured participants on their side-matched “involved”(7.41 [6.1°] vs 1.44 [4.8]°; η2=.34) and “uninvolved” (9.59 [8.5°] vs 2.16 [5.6°]; η2=.31) limbs, with a greater fractal dimension of the center-of-pressure path (involved limb=1.39 [0.16°] vs 1.25 [0.14°]; uninvolved limb=1.37 [0.21°] vs 1.23 [0.14°]). InterpretationBilateral impairment in postural control strategies present following a first time acute lateral ankle sprain.

Reliability and Validity of Kinect RGB-D Sensor for Assessing Standing Balance

Microsoft Kinect uses a built-in RGB-D sensor and the skeleton tracking algorithm to capture 3-D movements of the human body. It also has the potential for assessing postural stability, which is fundamental for most motor activities. The aim of this paper was to investigate whether standing balance can be evaluated reliably and validly by this low-cost device. Nine healthy subjects were required to maintain balance during three standing positions (double limb stance with feet apart, double limb stance with feet together and single limb stance). The center of mass (COM) was calculated from the body's kinematic data acquired by the Kinect system and Optotrak Certus motion capture system. The position variability and average velocity of the COM in the horizontal plane were calculated and used to evaluate the subject's balance. These COM parameters from the two systems showed excellent and comparable test-retest reliability (intraclass correlation coefficient ). In addition, although the average velocity of the COM calculated from Kinect was significantly lower, each COM parameter showed excellent concurrent validity and a significant linear relationship existed between the two systems, which meant that biases may be corrected using linear calibration equations. Therefore, Kinect may be a valid, reliable, and convenient device for assessing standing balance when its measured COM parameters are properly calibrated.

Effects of a Knee Varus Brace on Nonoperative Lateral Compartment Osteoarthritis

The aim of this study was to evaluate the effectiveness of the OAdjuster® (dj Orthopedics, Vista, CA, USA) brace on lateral compartment osteoarthritis (OA). The OAdjuster knee brace will effectively control joint angles in the frontal plane throughout the stance phase of the gait cycle. Two patients with valgus knee deformity diagnosed with lateral compartment OA in the right knee were included in this study. Both patients have been fitted with the OAdjuster knee brace in the treatment of OA. A subjective history was taken of each patient through a personal interview. Objective tests and measures were taken to rule out any other joint pathology. Each patient ambulated with and without the unloading brace and was filmed with two digital cameras. Analysis of joint angles and gait parameters was performed with the Ariel Performance Analysis System® (APAS) (Ariel Dynamics, Inc, San Diego, CA, USA). In case 1, the knee valgus angle at midstance decreased from 4.4° of valgus to 1.7° of valgus with the use of the brace. The hyperextension angle in the sagittal plane also decreased during single-limb stance on the braced limb from 12.1° to a neutral alignment. Other gait parameters in case 1 showed very little change with the use of the OAdjuster brace. Case 2 exhibited a decrease in valgus angle during midstance from 8.4° to 7.0°. The hyperextension angle during single-limb stance also decreased from 11.2° to 4.4°. Gait parameters also showed an improvement in case 2 with the use of the unloading brace. The OAdjuster brace may become a viable option for patients with lateral compartment OA and who are unable to undergo surgical procedures because of other comorbidities. The OAdjuster brace effectively controlled joint angles in the frontal and the sagittal plane throughout the stance phase of the gait cycle.

Balance failure in single limb stance due to ankle sprain injury: An analysis of center of pressure using the fractal dimension method

Instrumented postural control analysis plays an important role in evaluating the effects of injury on dynamic stability during balance tasks, and is often conveyed with measures based on the displacement of the center-of-pressure (COP) assessed with a force platform. However, the desired outcome of the task is frequently characterized by a loss of dynamic stability, secondary to injury. Typically, these failed trials are discarded during research investigations, with the potential loss of informative data pertaining to task success. The novelty of the present study is that COP characteristics of failed trials in injured participants are compared to successful trial data in another injured group, and a control group of participants, using the fractal dimension (FD) method. Three groups of participants attempted a task of eyes closed single limb stance (SLS): twenty-nine participants with acute ankle sprain successfully completed the task on their non-injured limb (successful injury group); twenty eight participants with acute ankle sprain failed their attempt on their injured limb (failed injury group); sixteen participants with no current injury successfully completed the task on their non-dominant limb (successful non-injured group). Between trial analyses of these groups revealed significant differences in COP trajectory FD (successful injury group: 1.58±0.06; failed injury group: 1.54±0.07; successful non-injured group: 1.64±0.06) with a large effect size (0.27). These findings demonstrate that successful eyes-closed SLS is characterized by a larger FD of the COP path when compared to failed trials, and that injury causes a decrease in COP path FD.

Postural control in children with and without neurofibromatosis type 1

Previous research has evaluated the motor proficiency of children with neurofibromatosis type 1 (NF1) and found delays on the balance subtest. However the balance subtest was found to have low sensitivity for identifying balance impairments. This study examines the differences in postural control between children with NF1 and peers with typical development using a force plate. A single limb stance test on a force plate was completed for all participants. The force plate variables, center of pressure maximum distance in the anterior/posterior direction (COPmax A/P) and center of pressure velocity (COPvel A/P) were compared between groups. The NF1 group’s performance was significantly poorer than the control group in both COPmax A/P (p=.01) and COPvel A/P (p=.01). When separated into specific age ranges, only the children in the NF1 group between 5 and 12years of age demonstrated statistically significant differences in the COP variables. The COP variables for the 13- to 18-year-old group were not significantly different. These results indicate that young children with NF1 have poor postural control. However, postural control appears to improve with maturation.

BALANCE FAILURE IN SINGLE LIMB STANCE DUE TO ANKLE SPRAIN INJURY: AN ANALYSIS OF CENTRE OF PRESSURE USING THE FRACTAL DIMENSION METHOD

BackgroundDynamic stability is ubiquitous to fulfilling daily living activities. Instrumented postural control analysis plays an important role in evaluating the effects of injury on dynamic stability during balance tasks, and...