The reflexive responses to resist external forces and maintain posture result from the coordination between the vestibular system, muscle, tendon, and joint proprioceptors, and vision. Aging deteriorates these crucial functions, increasing the risk of falls. This study aimed to verify whether a training program with water bags, an Instability Neuromuscular training (INT) using the inertial load of water, could positively impact balance ability and dynamic stability. This study was conducted with twenty-two healthy older women aged ≥ 65 (mean age: 74.82 ± 7.00 years, height: 154.20 ± 5.49 cm, weight: 55.84 ± 7.46 kg, BMI: 23.55 ± 3.58 kg/m²). The participants were randomly allocated into two groups: a group that used water bags and a control group performing bodyweight exercises. The intervention training lasted 12 weeks, with 2 sessions per week totaling 24 sessions, each lasting 60 min. The pre- and post-tests were compared using t-tests to examine within- and-between-group differences. The effect size was examined based on the interaction between group and time using a two-way repeated measures ANOVA. The Modified Timed Up and Go manual (TUG manual), Sharpened Romberg Test (SRT), and Y-balance test (YBT) were conducted to assess dynamic stability, including gait function, static stability, and reactive ability. In comparison between groups, the waterbag training group showed a decrease in task completion time associated with an increase in walking speed in the TUG manual test (p < 0.05), and an increase in static stability and reaction time in the Sharpened Romberg test with eyes closed (p < 0.05), and an increase in single-leg stance ability in both legs in the Y-balance test (p < 0.05). All statistical confidence interval levels were set 95%. INT using the inertial load of water enhanced the somatosensory system and gait related to dynamic stability in older women. Therefore, the clinical application of this training program is expected to reduce the risk of falls in healthy older women, improving dynamic stability related to gait.

Stair ambulation requires precise lower extremity control and postural stability. Middle-aged women with degenerative knee arthritis (DKA) are at an increased risk of falls, yet the effects of unstable load training on their postural stability remain underexplored. This study investigated the effects of a 10-week Aqua Vest-based unstable load training program on postural stability and pain during stair ambulation in middle-aged women with DKA. Thirty participants were randomly assigned to an exercise group (EG) or a control group (CG), with 15 participants in each group. The EG completed a 10-week Aqua Vest training program, while the CG received no intervention. Pre- and post-assessments included spatiotemporal parameters, lower extremity kinematics, and center of pressure (CoP) trajectories during stair descent, as well as knee pain evaluated by a visual analog scale (VAS). After training, the EG demonstrated significant improvements in spatiotemporal and kinematic parameters, reduced ML displacement, lower VAS scores, as well as significant changes in AP CoP parameters. These findings suggest that Aqua Vest-based unstable load training may enhance ML postural stability and alleviate pain in DKA patients, potentially contributing to enhanced balance function and improved stair ambulation safety.

Background: Gait decline in older adults is closely linked to reduced ankle propulsion and a compensatory reliance on proximal joints. This randomized trial investigated whether dynamic stability training using water inertia can improve gait mechanics and redistribute lower-limb joint moments in older women. Hypotheses: (1) The training would improve gait speed, stride length, and cadence. (2) The ankle plantar flexor moment and positive mechanical work would increase, while hip extension moment would decrease. Method: Twenty-four women aged 65 years and older were randomly assigned to either an experimental or control group. The experimental group wore a water-filled aquavest, and the control group wore a weighted vest. Both groups performed the same training program twice weekly for 12 weeks. Outcome measures included gait speed, stride length, cadence, ankle plantar flexion moment, hip extension moment, and positive mechanical work during terminal stance. A two-way mixed (between–within) analysis of variance (ANOVA) evaluated the group × time interaction effects. Results: Significant group × time interactions were found for gait speed (p < 0.001), stride length (p < 0.001), ankle moment (p = 0.017), and positive work (p < 0.001). Cadence increased in both groups over time (p < 0.05), with no interaction. The hip moment declined slightly in the experimental group. Conclusions: Water inertia load training enhanced propulsion and promoted an ankle-dominant gait, supporting its use to improve gait function and reduce proximal compensation in older women.

Objective: Head-to-head evidence comparing closed-kinetic-chain (CKC) and open-kinetic-chain (OKC) training on balance in middle-aged women with knee osteoarthritis (KOA) is limited. Purpose: To compare 10-week hip abduction/external rotation-focused CKC versus OKC on static and dynamic balance. Methods: Twenty-two women with KOA were randomized to CKC (n = 11) or OKC (n = 11) and trained twice weekly for 10 weeks. The primary outcome was the center of pressure (COP) during single-leg stance (AP/ML range, excursion, velocity, and RMS); the secondary outcome was the Y-Balance Test (YBT) composite score. Results: CKC produced significant within-group reductions across all COP variables and significant YBT increases for both affected and unaffected limbs (p < 0.05). OKC showed only small changes in select COP indices and no meaningful change in YBT. Post-intervention between-group comparisons consistently favored CKC for AP/ML and total COP excursion/velocity and for the YBT composite score (p < 0.05). Conclusions: Under weight-bearing conditions, a hip-focused CKC program that promotes multi-joint coordination and co-contraction yields broader and more consistent improvements in postural stability and dynamic balance than OKC in middle-aged women with KOA. These findings support prioritizing CKC when rehabilitation aims include gait and functional stability.

Background: Gait decline in older adults is closely linked to reduced ankle propulsion and compensatory reliance on proximal joints, such as the hip. This study examined whether dynamic stability training using water inertia can improve gait mechanics and redistribute lower limb joint moments in elderly women. Method: Twenty-four women aged 65 years and older were randomly assigned to either an experimental group or a control group. The experimental group performed dynamic stability training using an aqua vest filled with water to provide dynamic inertia load, while the control group used a weighted vest with an equivalent external load. Both groups participated in a 12-week intervention, training two times per week. Outcome variables included spatiotemporal gait parameters (gait speed, stride length, and cadence), peak ankle plantar flexion moment, hip extension moment, and positive mechanical work at the ankle during the terminal stance phase. A two-way repeated measures ANOVA was conducted to evaluate group × time interaction effects. Results: Significant group × time interactions were found for gait speed (p < 0.001), stride length (p < 0.001), ankle plantar flexion moment (p = 0.017), and positive mechanical work at the ankle (p = 0.001). The experimental group showed the most notable improvements between weeks 6 and 12, while the control group demonstrated limited changes beyond week 6. Cadence increased significantly over time in both groups (p < 0.05), although no group × time interaction was observed. Hip extension moment showed a non-significant downward trend in the experimental group, suggesting enhanced distal propulsion and reduced reliance on proximal compensatory strategies. Conclusion: Water-inertia load training improved propulsion efficiency and joint moment distribution, favoring an ankle-dominant strategy. These findings support the use of instability-based training to enhance gait function and reduce proximal compensatory patterns in older women.

Background: This study aimed to investigate how barbell type (elastic vs. inelastic) and lifting speed affect postural stability and lower limb muscle activation during the single-leg deadlift (SLDL), a common unilateral exercise in rehabilitation and performance training. Methods: Twenty-seven healthy adults performed SLDLs using both elastic and inelastic barbells under three lifting speeds (normal, fast, and power). Center of pressure (COP) displacement in the anterior–posterior (AP) and medial–lateral (ML) directions and electromyographic (EMG) activity of eight lower limb muscles were measured. Results: COP displacement was significantly lower when using elastic barbells (AP: F = 6.509, p = 0.017, η² = 0.200, ω² = 0.164; ML: F = 9.996, p = 0.004, η² = 0.278, ω² = 0.243). EMG activation was significantly higher for the gluteus medius, biceps femoris, semitendinosus, and gastrocnemius (all p < 0.01), especially under power conditions. Significant interactions between barbell type and speed were found for the gluteus medius (F = 13.737, p < 0.001, η² = 0.346, ω² = 0.176), semitendinosus (F = 6.757, p = 0.002, η² = 0.206, ω² = 0.080), and tibialis anterior (F = 3.617, p = 0.034, η² = 0.122, ω² = 0.029). Conclusions: The findings suggest that elastic barbells improve postural control and enhance neuromuscular activation during the SLDL, particularly at higher speeds. These results support the integration of elastic resistance in dynamic balance and injury prevention programs.