This study aimed to assess the influence of leg dominance on the symmetry of body balance during one-leg standing tasks. Methods: Ninety-six healthy adults were enrolled in this study. Leg dominance was defined using Waterloo Footedness Questionnaire-Revised (WFQ-R) and body balance was measured in one-leg standing test on firm surface (eyes open and closed) and on the foam surface (eyes open). Symmetry Index (SI) of balance parameters was correlated with the results of WFQ-R. Results: The analysis showed that each participant had better test results for one leg compared to the other, and for most participants and test conditions, the more stable lower limb was the right one. No significant correlations were found between WFQ-R and SI. Conclusions: Leg dominance does not seem to affect the ability to maintain body balance on one leg standing on a stable or foam surface within the conditions tested in this study. Nevertheless, some asymmetry between right and left leg standing is visible in healthy adults.

Smartphone use raises concerns about forward head posture, and the high cognitive load and reduced situational awareness involved increase fall risk. This study aimed to assess the impact of smartphone usage (both holding and texting) on fall risk and postural control in healthy young adults. Thirty-three young adults completed three identical 20-s trials in static (AMTI platform) and dynamic (Balance Biodex platform) conditions, including (1) the baseline (eyes open and standing still), (2) passive phone use (holding and looking at the phone with the screen off), and (3) a dual task (texting while standing). Postural control was assessed using linear measures (CoP path length and the Fall Risk Test index) and nonlinear metrics (sample entropy, fractal dimension, and the Lyapunov exponent). The results indicated that smartphone use, especially texting, significantly increased CoP variability in the anteroposterior direction and Fall Risk Test values, highlighting reduced stability. A nonlinear analysis revealed decreased adaptability and the complexity of postural control during phone use. These findings suggest that mobile phone interactions impair balance and increase fall risk due to cognitive and physical distractions.

Background: Postural symmetry ensures balanced alignment and equal weight distribution, promoting optimal function and minimizing stress on muscles and joints. This study aimed to evaluate lower limb movement symmetry in response to mechanical perturbations. Methods: Twelve healthy young women were subjected to mechanical perturbation tests while standing on the Motek GRAIL system treadmill. Maximum values of kinematic and kinetic parameters and symmetry indices were counted to compare the responses of dominant and non-dominant limbs. Results: The study identified symmetrical and asymmetrical features in lower limb dynamics. Symmetry nearness was observed in the ankle joint angle (SI = 0.03), the hip torque (SI = 0.03), and the vertical component of the ground reaction force (SI = 0.04). However, significant asymmetries were found in the medio-lateral component of the ground reaction force (SI = 1.84), ankle torque (SI = 0.23), knee torque (SI = 0.19), hip angle (SI = 0.15), and knee angle (SI = 0.08). The anterior–posterior component of the ground reaction force (SI = 0.14) showed asymmetry but was not statistically significant. Conclusions: Perturbations impact lower limb dynamics, revealing dominance- and joint-specific asymmetries. Bilateral assessment is crucial for understanding postural control, guiding rehabilitation to restore symmetry, and reducing the risk of injuries, falls, and musculoskeletal strain, particularly in athletes and older adults. These findings emphasize the value of symmetry indices in optimizing therapy and prevention strategies.

Background: Postural control in healthy young adults involves complex neuromuscular processes; however, the kinematic and kinetic consequences of small, forward leg perturbations in a defined population are not fully described. This study aimed to characterize the kinematic and kinetic consequences of forward leg perturbations during quiet standing. Methods: This investigation used a quasi-experimental repeated-measures design. Sixteen healthy young women (20.1 ± 0.7 years), all right-leg dominant, were tested using the Gait Real-Time Analysis Interactive Laboratory (GRAIL) system. Forward treadmill perturbations were applied to each limb during quiet standing, and joint angles, ground reaction forces, and torques were measured across baseline, perturbation, and response phases. As the data were non-normally distributed, paired comparisons were conducted using the Wilcoxon test, with significance set at p < 0.05 (Bonferroni corrected) and effect sizes (r) reported. Results: Joint angles remained symmetrical between limbs (no significant differences after correction). In contrast, kinetic measures showed clear asymmetries: at baseline, the dominant limb produced greater knee torque (p = 0.0003, r = 0.73), ankle torque (p = 0.0003, r = 0.76), and medio-lateral GRF (p = 0.0003, r = 0.87). During perturbation, it again generated higher knee (p = 0.0036, r = 0.43) and ankle torques (p = 0.0003, r = 0.53), with larger medio-lateral GRF (p = 0.0003, r = 0.87). In the response phase, the dominant limb showed greater hip torque (p = 0.0033, r = 0.43) and a small dorsiflexion shift at the ankle (p = 0.0066, r = 0.41). Anterior–posterior GRF changes were minor and non-significant after correction. Conclusions: Induced forward leg movements caused limb-specific kinetic adjustments while maintaining overall kinematic symmetry. The dominant leg contributed more actively to balance recovery, highlighting its role in stabilizing posture under small perturbations. These findings are specific to the studied demographic and should not be generalized to males, older adults, left-dominant individuals, or clinical populations without further research.