The effects of a perturbation-based balance training on the reactive neuromuscular control in community-dwelling older women: a randomized controlled trial

Purpose
The purpose of this study was to evaluate the effects of short-term perturbation-based balance training and a detraining period on postural control in older adults.

Methods
A group of healthy older women were recruited and divided into two groups: an exercise group (EG, n = 21, age = 67.0 ± 2.0 y) that performed balance-based exercises three times a week over a sixweek period and a control group (CG, n = 20, age = 67.9 ± 3.1 y). Center-of-pressure displacement (CoP) and electromyographic data (EMG onset, time-to-peak and amplitude) were assessed during forward and backward perturbations for six leg muscles. All variables were analyzed before the training program began, at its end, and after a six-week period of detraining. A mixed ANOVA model was used to analyze the within- and between-subject results.

Results
A decrease in backward CoP displacement, EMG onset and time-to-peak of the ankle muscles, especially the tibialis anterior (TA) and gastrocnemius (MG), was observed. Improvement in muscle EMG amplitude for the ankle muscles (TA, MG and Soleus - SO) at the early phase (0-200 ms) of the perturbation test, with the SO also showing an increase in amplitude at the intermediate phase (201-400 ms). After the detraining period, only the TA muscle maintained an improvement in reaction time.

Conclusions
Perturbation-based balance training improved neuromuscular responses such as muscle reaction time and ankle muscle activation and consequently aided the body’s ability to maintain correct center of pressure, although after a period of detraining this gain was not maintained for most of the assessed variables.