Changes in Postural Control After a Ball-Kicking Balance Exercise in Individuals With Chronic Ankle Instability

Abstract

Context: Rehabilitation programs for patients with chronic ankle instability (CAI) generally involve balance-perturbation training (BPT). Anticipatory postural adjustments (APAs) and compensatory postural adjustments (CPAs) are the primary strategies used to maintain equilibrium during body perturbations. Little is known, however, about how APAs and CPAs are modified to promote better postural control for individuals with CAI after BPT.

Objective: To investigate the effect of BPT that involves kicking a ball on postural-control strategies in individuals with CAI.

Design: Randomized controlled clinical trial.

Setting: Laboratory.

Patients or other participants: We randomly assigned 44 volunteers with CAI to either a training group (TG; 11 women, 11 men; age = 24 ± 4 years, height = 173.0 ± 9.8 cm, mass = 72.64 ± 11.98 kg) or control group (CG; 11 women, 11 men; age = 22 ± 3 years, height = 171.0 ± 9.7 cm, mass = 70.00 ± 11.03 kg).

Intervention(s): The TG performed a single 30-minute training session that involved kicking a ball while standing on 1 foot. The CG received no intervention.

Main outcome measure(s): The primary outcome was the sum of the integrated electromyographic activity (∑∫EMG) of the lower extremity muscles in the supporting limb that were calculated during typical intervals for APAs and CPAs. A secondary outcome was center-of-pressure displacement during similar intervals.

Results: In the TG after training, the ∑∫EMG decreased in both dorsal and ventral muscles during compensatory adjustment (ie, the time interval that followed lower limb movement). During this interval, muscle activity (∑∫EMG) was less in the TG than in the CG. Consequently, center-of-pressure displacement increased during the task after training.

Conclusions: A single session of ball-kicking BPT promoted changes in postural-control strategies in individuals with CAI. These results should stimulate new and more comprehensive studies to investigate the effect of this and other BPT techniques on postural control in patients with CAI.

Keywords: balance training; reactive responses; recurrent sprains.

Figure 1.

Participant flow chart.

Figure 2.

Representation of the experimental tasks and balance training protocol. A, Experiment 1: the single-legged stance during the static task. B, Experiment 2: the ball launcher and a participant performing the kicking task (dynamic task). C, The balance-training protocol.