Age-related declines in dynamic balance and cognitive control increase fall risk in older adults (OA). Non-invasive brain stimulation, such as anodal transcranial direct current stimulation (a-tDCS), may enhance training outcomes. However, it remains unclear whether stimulation over motor or prefrontal regions is more effective for improving dynamic balance training (DBT) in OA. To compare the effects of a-tDCS over the primary motor cortex (M1) vs. dorsolateral prefrontal cortex (DLPFC) on DBT performance and transfer to static balance in OA, and to explore whether baseline resting-state EEG predicts training outcomes. In a randomized crossover design, 18 healthy OA completed DBT training during three stimulation conditions (M1, DLPFC, and sham). Static balance performance was assessed before and after training. Resting-state EEG was recorded to assess predictors of training success. DBT performance improved significantly more with DLPFC stimulation than with M1 or sham. Negative transfer effects were observed on untrained static balance tasks. Lower baseline alpha power predicted stronger training gains with DLPFC stimulation but weaker gains with M1 stimulation. DLPFC-targeted a-tDCS enhances DBT in OA more effectively than M1 stimulation. Baseline oscillatory brain activity may inform individualized stimulation protocols to optimize balance training outcomes in OA.

This study examined the acute effect of training on postural balance among young dinghy sailors. By measuring sway path and sway area of the center of pressure (CoP), the objective was to investigate whether training sessions on dinghy sailboat influence sway path and sway area measurements. Twelve competitive sailors (Optimist and Laser Radial class) performed a set of balance tests on both stable and unstable surfaces, with open and closed eyes, measured over three days. The first day served to familiarize the participants with the protocol. On the second and third days, CoP sway path and sway areas were assessed before, during and after the training session using a Wii Balance Board (WBB). A general improvement in balance control was observed in most of the measured parameters. Statistical analysis (RM ANOVA) revealed significant reductions in sway path and sway area with closed eyes on an unstable surface comparing pre-, during- and post- measurement on the second day (p < 0.05), and for sway path with open and closed eyes on an unstable surface on the third day (p < 0.05). Findings of the present study show a short-term effect of sailing sessions on balance, suggesting that a single training session can induce acute improvements in postural control among young athletes. It is possible that the observed acute improvements are associated with immediate neuromuscular adaptation following sailing activity, specifically due to the unpredictable and dynamic environment in which sailing takes place. However, the temporal duration of this effect appears to be limited. As balance is an essential skill in sailing performance, future studies should investigate long-term effects and retention of training-induced improvements in postural control.

Muscle co-activation, the simultaneous activation of muscles or muscle groups, is a common strategy to enhance the stability of the musculoskeletal system. However, co-activation can also be the consequence of underlying neurological impairments. To better understand and discern functional co-activation during walking, this study explored the difference in quadriceps-hamstrings co-activation during the swing phase of walking and an isolated leg-swinging movement in healthy adults. Twelve healthy young adults performed walking and isolated leg-swinging at slow (0.6 m/s) and comfortable speed. Isolated leg-swinging was frequency and amplitude matched to the walk conditions. Electromyography signals from quadriceps muscles: m. vastus lateralis and m. rectus femoris, and hamstring muscles: m. biceps femoris and m. semitendinosus were recorded. Co-activation indices (CI) were determined across the quadricep-hamstrings using two metrics: 1) Pearson correlation coefficient (Pearson-CI) was calculated as to quantify rate of co-activation. 2) Area under the curve (AUC-CI) was calculated as a measure of co-activation magnitude Both metrics were averaged to a single quadriceps-hamstrings CI for each metric. The results showed a higher Pearson-CI, but not AUC-CI, during walking compared to isolated leg-swinging, specifically during mid- and terminal-swing at both speeds. AUC-CI, but not Pearson-CI, was significantly higher during slow speed, compared to comfortable speed. Quadriceps-hamstrings co-activation towards the end of the swing phase during walking reflects preparation for heel-strike, which is not present in isolated leg-swinging. Therefore, an isolated leg-swinging task could serve as a feasible method to distinguish pathological from functional muscle co-activation during walking.