Acute effects of short-term stretching of the triceps surae on ankle mobility and gait initiation in patients with Parkinson's disease.

Background: Ankle mobility is known to be of uttermost importance to generate propulsive forces and control balance during gait initiation. Impaired mobility of the postural chain occurs with normal ageing and is exacerbated in patients with Parkinson's disease. This study questions whether short-term stretching session applied to the triceps surae improves ankle mobility and, consequently, dynamical postural control in patients with Parkinson's disease performing gait initiation.

Method: Nineteen patients with Parkinson's disease participated in this study and were randomly assigned to an "intervention group" or a "sham group". In the intervention group, patients were exposed to a 4 × 60 seconds triceps surae stretching. In the sham group, they were exposed to forearm stretching. Additionally, ten age-matched healthy elderly, who were not exposed to any stretching-treatment, were assigned to a "control group". Participants performed series of gait initiation on a force-plate before and after their treatment.

Findings: Ankle mobility was improved in the intervention group after triceps surae stretching. The forward velocity of the center-of-mass at heel-off and motor performance related-parameters (progression velocity, center-of-mass velocity at foot-contact and swing phase duration) were also improved in the intervention group, with large effect sizes (d ≥ 0.8). None of the stability parameters were modified by the treatments.

Interpretation: Short-term triceps surae stretching is an efficient method to increase ankle mobility and improve the capacity to generate forward propulsive forces in patients with Parkinson's disease. These findings are congruent with the "posturo-kinetics capacity" theory according to which dynamical postural control depends on postural chain mobility.