A Single-Session Training of Ball Throwing Exercise Improves Balance Control in Individuals with Multiple Sclerosis

Background: Impaired balance control is a common and often an initial disabling symptom of multiple sclerosis (MS).  Balance deficit is a major cause of falls resulting in significant declines in mobility and activity levels in individuals with MS.  There is a need to develop new rehabilitation approaches enhancing balance control in MS.

Objectives: The study was conducted to investigate the feasibility of short-term training in improvement of anticipatory postural adjustments (APAs) and its effect on subsequent control of posture in individuals with MS.

Methods: Eight individuals with relapsing-remitting MS participated in the laboratory tests before (pre-training) and after (post-training) a single training session consisting of throwing a medicine ball.  Two perturbation tasks contained predictable self-initiated perturbations induced by bilateral shoulder flexion and externally induced perturbations created by the pendulum impact.  The EMG activity of trunk and leg muscles and center of pressure (COP) displacements were recorded before and immediately after a single training session.  Muscle latencies, EMG integrals and COP displacements were analyzed during the anticipatory and compensatory phases of postural control.

Results: The training resulted in enhancement of the generation of APAs seen as significantly early onsets of leg and trunk muscle activity prior to the bilateral arm flexion task (p<.05).  Significantly early activation of postural muscles was observed prior to the predictable external perturbation, even the task was not a part of training, indicating the transfer of the effect of the single training session.  Significantly larger EMG integrals (calculated for 4 epochs, each of 150 ms duration in relation to the perturbation onset) were observed after training in most of the muscles (p<.05).  COP displacements after perturbation, that represent postural control during the balance restoration phase, were improved after training (p<.05).

Conclusions: Individuals with MS can improve their ability to use predictive responses for postural control after a single-session training.  The observed training-related improvements of balance control suggest that focused rehabilitation could be effective in improving postural control and as a result enhance mobility and quality of life in individuals with MS.