Ankle dorsiflexor, not plantarflexor strength, predicts the functional mobility of people with spastic hemiplegia

To determine the relationships between affected ankle dorsiflexion strength, other ankle muscle strength measurements, plantarflexor spasticity, and Timed "Up & Go" (TUG) times in people with spastic hemiplegia after stroke.

A cross-sectional study.

A university-based rehabilitation centre.

Seventy-three subjects with spastic hemiplegia.

Functional mobility was assessed using TUG times. Plantarflexor spasticity was measured using the Composite Spasticity Scale. Affected and unaffected ankle dorsiflexion and plantarflexion strength were recorded using a load-cell mounted on a foot support with the knee bent at 50º and subjects in supine lying.

TUG times demonstrated strong negative correlation with affected ankle dorsiflexion strength (r = -0.67, p ≤ 0.001) and weak negative correlations with other ankle muscle strength measurements (r = -0.28 to -0.31, p ≤ 0.05), but no significant correlation with plantarflexor spasticity. A linear regression model showed that affected ankle dorsiflexion strength was independently associated with TUG times and accounted for 27.5% of the variance. The whole model explained 47.5% of the variance in TUG times.

Affected ankle dorsiflexion strength is a crucial component in determining the TUG performance, which is thought to reflect functional mobility in subjects with spastic hemiplegia.