Search Results (87)

Background/Objectives: This study aimed to assess the impact of a physio-feedback exercise program (PEER) on the static balance of community-dwelling older adults. Methods: A clustered randomized controlled trial involving community-dwelling older adults (≥60 years of age) in the Central Florida area was conducted. Participants were randomized by research site into either (1) an 8-week exercise intervention program consisting of group-based and at-home exercises, along with a discussion with a researcher regarding their physiological health before and after the intervention period, or (2) a control group. Static balance outcomes included anterior–posterior root mean square (AP RMS), medial-lateral RMS (ML RMS), sway speed variability, and sway area measured using the Balance Tracking System (BTrackS) at baseline (T1), post-intervention (T2), one-month post-intervention (T3), and three months post-intervention (T4). Results: Among 373 community-dwelling older adults (mean age = 74.3 ± 7.1 years), a trend towards short-term improvement of sway area was observed for the intervention group, as seen through a small, marginally significant reduction in sway area at T2 (standardized β = −0.07; p = 0.050). However, the trend dissipated during post-intervention follow-up periods (T3 and T4). Sway speed variability significantly increased for the intervention group at T4 (standardized β = 0.10; p = 0.014). Conclusions: The PEER intervention may need to increase the total duration of the intervention, the frequency of the weekly exercise sessions, and the amount of standing stance exercises during the group-based and at-home exercise sessions to elicit improvements in static balance among older community-dwelling adults. Full article

This paper develops accurate three-dimensional trajectory tracking and anti-sway control strategies for offshore container cranes operating in an open-sea environment. A 5-DOF nonlinear dynamic model is developed that simultaneously accounts for the crane’s structural motion, trolley movement, spreader hoisting with variable rope length, and both lateral and longitudinal payload sway. The model further incorporates external disturbances induced by wave-excited ship motions. To ensure smooth, efficient, and accurate load transportation from the initial to the target position, an effective trajectory-planning scheme is proposed using a quintic polynomial trajectory refined by a ZVD shaper to suppress residual oscillations. A sliding mode control method is then designed to achieve accurate trajectory tracking and load-sway suppression under external disturbances. Numerical simulations demonstrate that the proposed trajectory planning method effectively reduces the residual oscillations and verifies the effectiveness and robustness of the proposed sliding mode control strategy. Full article

Background/Objective: Postural control differs between individuals with lower limb amputation and the general population. Although previous studies examined the effects of unexpected surface perturbations on postural control in individuals with transtibial amputation (TTA) and individuals with transfemoral amputation (TFA), their impact on lower limb muscle activation remains unclear. This study aimed to assess postural control on a stable surface and to evaluate the effects of unexpected surface perturbations on lower limb muscle activation in unilateral TTAs, TFAs, and in a healthy control group (CG). Methods: The study included 10 TTAs, 9 TFAs, and 10 healthy controls. Postural control was assessed using a force platform, and lower limb muscle activity was recorded with surface electromyography during unexpected surface perturbations. Results: The TFAs showed the highest anteroposterior and lateral postural sway under compliant surface eyes closed and the highest lateral sway under normal surface eyes closed, whereas the CG showed the lowest values (p < 0.05). During forward perturbations, rectus femoris (RF) and tibialis anterior (TA) activations were significantly higher than biceps femoris (BF) and medial head of the gastrocnemius (GM) activations, respectively, across all groups (p < 0.05). During backward perturbations, GM activations exceeded TA activations in all groups, while BF activations were higher than RF only in TTAs (p < 0.05). Significant group effects were found for RF and BF during forward perturbations, and side effects for BF (forward) and RF (backward) activations (p < 0.05). Conclusions: Postural control responses vary with the level of lower limb amputation. TFAs relied more on visual input during quiet standing, whereas TTAs demonstrated greater reliance on thigh muscle activation during surface perturbations. These findings highlight the need to consider amputation level in balance and rehabilitation programs. Full article

Objective: This study aimed to investigate the effects of dual-task stroboscopic visual training (DTSVT) on balance, functional mobility, and gait in children who are hard-of-hearing. Methods: This randomized controlled study included 31 children (17 girls, 14 boys) with congenital sensorineural hearing loss. Participants were assigned to one of three groups: control group, conventional balance training (CBT) group, and DTSVT group. The CBT and DTSVT groups participated in an exercise program for 16 weeks, twice weekly, for 40 min (a total of 24 sessions). Static balance was assessed using the Tandem Romberg test and Single-Leg Stance (SLS) test, while dynamic balance was evaluated using the Functional Reach Test (FRT), balance disc test, and the Four Square Step Test (FSST). The Pediatric Balance Scale (PBS) was used as a subjective balance assessment. Functional mobility was assessed using the Timed Up and Go (TUG) Test, Step Test, 10 m Walk Test (10 MWT), and Functional Gait Assessment (FGA). Postural sway parameters were recorded using the GyKo device, including Sway Area (EA, cm²), Distance Length (DL, cm), Length (anterior–posterior (AP)) (cm), Length (medial–lateral (ML)) (cm), Mean Distance (D) (cm), Mean Distance (AP) (cm), and Mean Distance (ML) (cm). Results: Significant between-group differences were primarily observed in favor of the DTSVT group post-treatment, particularly in PBS scores, GyKoDL values during the eyes-open SLS test, and TUG test completion times (p < 0.05). Some baseline differences were noted among groups in functional reach distance, FSST completion time, and eyes-closed duration on the Balance Disc test (p < 0.05). Within-group comparisons revealed significant improvements in FSST times in both intervention groups, reduced postural sway parameters during the FRT in the DTSVT and control groups, and increased eyes-closed Tandem Romberg duration in the CBT group (p < 0.05). Most other outcome measures did not demonstrate statistically significant changes either within or between groups (p > 0.05). Conclusions: Dual-task stroboscopic visual training was more effective than conventional balance training in improving specific aspects of balance and functional mobility in children who are hard-of-hearing. These findings highlight the potential of adding cognitively demanding and visually engaging balance tasks to rehabilitation programs for this population. Larger and more diverse samples in future studies are needed to enhance the generalizability of these results. Studies that assess balance and gait using standardized clinical or laboratory tests may be particularly valuable. Given the small sample size and multiple comparisons, the results should be considered preliminary and exploratory. Full article

Objectives: This study examined whether moving tactile stimuli applied to the soles along the anterior–posterior (AP) and medial–lateral (ML) axes induce body sway during quiet stance. Methods: Fifteen healthy participants in quiet stance received plantar moving tactile stimuli along the AP or ML axis under occluded and unoccluded vision conditions. Results: The center of pressure (COP) along the ML axis was dependent on the phase of moving tactile stimuli along the ML axis under occluded vision condition. The direction of body sway was opposite to the stimulus loci. The total COP displacement during moving tactile stimuli along the AP axis was larger than that without stimuli, particularly under occluded vision conditions. Discussion: Humans likely perceive body sway towards the stimulated side. Based on this, when humans perceive body sway along the ML axis, they compensate for it by swaying the body in the direction contralateral to the stimulated side. Body sway along the ML axis, in accordance with the plantar loci receiving input of moving tactile sensation along the same axis, becomes apparent under occluded vision condition. Through intermodal reweighting, the contribution of tactile sensation to the control of body sway along the AP axis increases to compensate for the lack of visual input regulating body sway along this axis. Full article

Balance is a fundamental quality for trampoline athletes, the basis for completing complex skills. We aimed to compare balance control strategies between elite trampolinists (ETs) and sub-elite trampolinists (Sub-ET) by integrating linear and nonlinear center of pressure (COP) measures across stable and unstable surfaces. Twenty-four male athletes (12 ET, 12 Sub-ET) participated. Each participant performed 15-s static standing trials with eyes closed on a firm surface (FI) and a foam surface (FO). COP parameters were extracted, including ellipse area, sway velocity, sway range, and sample entropy (SampEn) in the medio-lateral (ML) and antero-posterior (AP) directions. Repeated-measures ANOVA was applied to examine the effects of group and surface condition. Linear analyses indicated that ET athletes exhibited greater sway amplitudes and faster velocities than Sub-ET athletes, with both groups showing larger sway on FO compared with FI. Nonlinear analyses revealed that ET athletes demonstrated lower SampEn, suggesting more structured and automatized control strategies. ET athletes maintained consistent entropy across both conditions, reflecting stronger adaptability to unstable surfaces. These results emphasize the importance of combining linear and nonlinear measures in balance assessment and suggest that incorporating unstable or trampoline-like surfaces into training may enhance adaptability, improve performance, and reduce injury risk. Full article

Background/Objectives: The study explored differences in gait characteristics and biomechanics according to rehabilitation aid use (normal gait (NG) vs. assisted gait (AG) groups) and obstacle height (0, 5, and 15 cm conditions) in patients with stroke-induced foot drop. Methods: A longitudinal study, within-subjects, repeated-measures study was conducted in 10 patients with mild foot drop. Participants walked at their preferred speed on a 10-m indoor track while crossing obstacles of three heights (0, 5, and 15 cm) under two gait conditions (normal walking (NG) and assisted walking (AG). The order of gait conditions and obstacle heights was randomized clinical within participants. Synchronized 3D motion capture with force plate measurements was used to calculate spatiotemporal variables, including ground reaction force (GRF), lower extremity joint angles at heel contact (HC), and toe-off (TO). A two-way repeated-measures ANOVA was used to examine the main effects and interaction effects of gait condition (NG vs. AG) and obstacle height (0, 5, and 15 cm). Results: AG showed little change in gait pattern, while there was a significant interaction between height and group. The vertical GRF (Fz) was lower in AG than NG at 5 cm, indicating reduced initial impact. There was a significant interaction for right medial–lateral (ML) GRF, with AG showing a small ML directional GRF over low obstacles (0–5 cm). At HC, AG was associated with an increase in right ankle dorsiflexion and right knee flexion. AG led to a reduction in left hip angle in the sagittal plane, and a smaller right ankle angle in the frontal plane, suppressing ML sway. At TO, AG caused an increase in right knee flexion, and bilateral ankle angles in the frontal plane at 5 cm. Conclusions: Rehabilitation aids reduced impact at initial contact, enhanced frontal plane stability, improved knee flexion and ankle alignment during the propulsion transition phase, and contributed to reduced variability and improved gait stability. The findings suggest potential utility for public health implications ambulation over curbs and thresholds, warranting larger, adequately powered clinical outcome trials. Full article

This study systematically evaluated postural control performance on dominant and non-dominant sides in young adults of different sexes using a Third-Order Polynomial Decay fitting method combined with time-domain stability features. A total of 126 participants (66 males, 60 females) performed single-leg landing tasks, during which ground reaction forces (GRF) and center of pressure (COP) data were collected using a Kistler 3D force platform and Bioware acquisition system. Dynamic stability times in the anterior–posterior, medial–lateral, and vertical directions were calculated with polynomial fitting, and additional time-domain measures were used to assess static and dynamic stability. Results showed that on the non-dominant side, participants exhibited significantly longer dynamic stability times (p = 0.015), greater root mean square distance (p = 0.005), and longer total sway path (p = 0.005) in the anterior–posterior direction compared with the dominant side. Significant sex differences were also found in vertical stability index (p = 0.044), dynamic stability index (p = 0.047), total sway path (p < 0.001), anterior–posterior sway path (p = 0.001), and medial–lateral sway path (p < 0.001). In conclusion, the dominant limb demonstrated superior stability, males showed better static control, and females displayed greater dynamic stability, underscoring the importance of targeted non-dominant training and sex-specific balance strategies. Full article

Archery performance is substantially influenced by postural stability. Although archery is commonly practiced outdoors, most studies have focused on short-distance indoor environments. Accordingly, this study examined the correlation between postural stability and shooting accuracy in competitive recurve and compound archers on a standard outdoor field (70 m for recurve and 50 m for compound). This study included 37 archers. Each archer’s performance was recorded during a simulated competition. Measurements included muscle strength, body stability, and center of pressure. Postural stability data were analyzed at 0.5 s before and 0.1 s after arrow release. The results indicated that compared with compound archers, recurve archers had stronger upper-limb muscles and exhibited lower pre-release total center of pressure (51.9 mm; p = 0.022) and medial/lateral sway (1.1 mm; p = 0.043). The compound archers exhibited lower post-release anterior/posterior sway (3.2 mm; p = 0.001) and lower angular velocities in most body segments, except for the lower back. The recurve archers relied more on post-release stability, whereas the compound archers relied more on pre-release control. Linear regression analysis identified different predictors of scoring accuracy for each bow type. Our findings highlight the need for discipline-specific training strategies, such as enhancing bow-side stability for recurve archers and drawing-side control for compound archers. Full article

Multiple Sclerosis (MS) is a chronic neurological disorder affecting the central nervous system that significantly impairs postural control and functional abilities. Robotic-assisted gait training mitigates this functional deterioration. This preliminary study aims to investigate the effects of a four-week gait training with the ExoAtlet II exoskeleton on static balance control and functional mobility in five individuals with MS (Expanded Disability Status Scale ≤ 2.5). Before and after the training, they were assessed in quiet standing under Eyes Open (EO) and Eyes Closed (EC) conditions and with the Timed Up and Go (TUG) test. Center of Pressure (CoP) Sway Area, Antero–Posterior (AP) and Medio–Lateral (ML) CoP displacement, Stay Time, and Total Instability Duration were computed. TUG test Total Duration, sit-to-stand, stand-to-sit, and linear walking phase duration were analyzed. To establish target reference values for rehabilitation advancement, the same evaluations were performed on a matched healthy cohort. After the training, an improvement in static balance with EO was observed towards HS values (reduced Sway Area, AP and ML CoP displacement, and Total Instability Duration and increased Stay Time). Enhancements under EC condition were less marked. TUG test performance improved, particularly in the stand-to-sit phase. These preliminary findings suggest functional benefits of exoskeleton gait training for individuals with MS. Full article

The Fall Risk Appraisal Matrix (FRAM) is a simple fall risk assessment tool that categorizes older adults into four separate groups based on their fear of falling (FOF) and static balance performance. Static balance for the FRAM is evaluated solely by postural sway distance, which does not account for other static balance parameters, such as sway area, anterior–posterior (AP) sway range, medial–lateral (ML) sway range, and sway velocity. The objective of this study was to compare these additional metrics across the FRAM groups to assess their relevance and validity for inclusion in static balance performance assessment. Hence, these measures were compared among the four different fall risk groups within the FRAM (203 participants; mean age = 75.0 ± 7.2 years) using Kruskal–Wallis test, followed by Dunn’s post hoc tests with Bonferroni correction. All balance metrics were significantly greater in the Incongruent (poor balance/low FOF) and Congruent (poor balance/high FOF) groups than the Rational (good balance/low FOF) group, as well as in the Congruent group than the Irrational (good balance/high FOF) group (p < 0.001). Additionally, AP sway range and sway velocity significantly differed between the Irrational and Incongruent groups (p < 0.001). The results suggest that the inclusion of these additional static balance measures, in addition to sway distance, reveals specific tendencies in static balance among different fall risk groups, which can serve as a reference for other researchers and future studies to develop more individually tailored intervention programs based on their static balance specificities. Full article

Background and Objectives: Gait and posture alterations are reported in patients with diabetic foot. We evaluated whether gait and postural parameters are associated with a well-known parameter, e.g., glycated hemoglobin levels in blood, and the salivary markers 1,5-anhydro-D-glucitol (1,5-AG) and Advanced Glycation End-Products (AGEs) measured in saliva samples. Materials and Methods: Gait and postural impairment was assessed using a wearable inertial sensor, and the evaluation of balance/gait and risk of fall was determined by the Tinetti Scale and Downton Index, respectively. Glycemic control was measured by glycated hemoglobin concentration and fasting glycemia. The salivary concentration of 1,5-AG and AGEs was measured using an enzyme-linked immunosorbent assay. Results: Eighty-five patients were evaluated, revealing significant associations (p < 0.05) between salivary 1,5-AG and sway path displacement along the medio-lateral axis (rho = 0.365, p = 0.017) and sway area (rho = 0.334, p = 0.031) during tandem position tests with eyes closed. Salivary AGEs were significantly associated with sway path displacement along the anterior–posterior axis (rho = 0.419, p = 0.004) and medio-lateral axis (rho = 0.436, p = 0.002) in the tests performed with eyes closed, feet close together, and foam pads, as well as with sway area (rho = 0.387, p = 0.007). The concentration of HbA1c was significantly correlated with sway path displacement along the anterior–posterior axis in the tests performed with eyes closed, feet close together, and foam pads (rho = 0.236, p = 0.043), as well as with sway area (rho = −0.236, p = 0.043). A significant difference was observed in the salivary AGE concentration between patients with previous ulcers versus those without (p = 0.035). By applying Bonferroni correction for multiple comparisons, the associations remained significant (p < 0.05) for AGE concentration in saliva and postural instability parameters. Conclusions: The results suggest a link between salivary glycemic control biomarkers, in particular AGEs and postural changes in patients with diabetic foot, indicating a new interesting filed for further studies on fall risk. Full article

This study aimed to investigate the relationship between visual system parameters (visual acuity and refractive error) and postural balance under controlled conditions in elite football players. Visual acuity (monocular and binocular) and refractive errors were assessed in 34 male athletes using retinoscopy and subjective refraction. Postural stability was assessed with the Cyber-Sabots™ platform, recording the center of pressure (CoP) metrics, including sway amplitude, velocity, and distribution area. Visual and postural parameter correlations were assessed using Pearson’s test (p < 0.05). Athletes demonstrated good binocular visual acuity (−0.03 ± 0.09 logMAR) and were predominantly emmetropic. Visual acuity and postural parameters showed significant negative correlations, whereby visual acuity was associated with reduced CoP displacement (r = −0.352) and sway area (r = −0.367), indicating enhanced stability. Hyperopia and oblique astigmatism were moderately correlated with increased sway (r = 0.343) and antero-posterior sway amplitude in the sagittal plane (r = 0.324). Anisometropia showed moderately negative correlations with antero-posterior control (r = −0.421), suggesting a disruptive effect on postural stability. The postural analysis showed adaptations characteristic of football players, including anterior body inclination, increased forefoot loading, and medio-lateral sway. Romberg’s quotients highlighted significant visual input reliance for maintaining postural balance. Visual acuity, refractive errors, and interocular refractive asymmetries significantly influence postural stability in elite football players. These results support incorporating visual function assessment into training and injury prevention in elite sports. Full article

The aim of this pilot study was to investigate the feasibility of markerless tracking to assess upper body movements of children with and without human immunodeficiency virus encephalopathy (HIV-E). Sagittal and frontal video recordings were used to track anatomical landmarks with the DeepLabCut pre-trained human model in five children with HIV-E and five typically developing (TD) children to calculate shoulder flexion/extension, shoulder abduction/adduction, elbow flexion/extension and trunk lateral sway. Differences in joint angle trajectories of the two cohorts were investigated using a one-dimensional statistical parametric mapping method. Children with HIV-E showed a larger range of motion in shoulder abduction and trunk sway than TD children. In addition, they showed more shoulder extension and more lateral trunk sway compared to TD children. Markerless tracking was feasible for 2D movement analysis and sensitive to observe expected differences in upper limb and trunk sway movements between children with and without HIVE. Therefore, it could serve as a useful alternative in settings where expensive gait laboratory instruments are unavailable, for example, in clinical centers in low- to middle-income countries. Future research is needed to explore 3D markerless movement analysis systems and investigate the reliability and validity of these systems against the gold standard 3D marker-based systems that are currently used in clinical practice. Full article

Objectives: Altered body biomechanics during pregnancy can lead to balance impairments and an increased risk of falls. Clinical exercise interventions can help regulate these biomechanical changes. Methods: A total of 101 pregnant participants (exercise group: n = 50; control group: n = 51) were retrospectively analyzed over an 8-week follow-up period. Single-leg balance parameters, including AP sway, ML sway, total body sway, OSD, and center of pressure velocity and acceleration, were assessed considering limb dominance. Measurements were taken at baseline and week 8. Repeated-measures ANOVA was used to analyze time–group interactions, with significance set at p < 0.001. The biomechanical impacts of participant height and body mass on center of pressure dynamics were also considered. Results: The exercise group (EG) demonstrated significant improvements in all balance parameters compared to the control group (CG) (p < 0.001), except for non-dominant anterior-posterior (AP) sway (p = 0.512). In the EG, medio-lateral (ML) and AP sway of the non-dominant limb were minimized, whereas these parameters were significantly increased in the CG. Although both groups exhibited an increased one-leg stance duration (OSD), the improvement was more pronounced in the EG. The controlled improvements observed in the EG suggest a protective effect of exercise on balance, particularly in the dominant limb. Conclusions: Clinical exercise interventions during pregnancy enhance balance parameters, reduce fall risk, and improve functional mobility. These findings suggest that structured exercise programs not only support maternal well-being but also improve reactive balance control. Given the biomechanical changes throughout pregnancy, future studies should examine the center of pressure velocity, acceleration, and the influence of maternal anthropometrics on postural stability to refine exercise recommendations. Full article