The Strength of the Ankle Dorsiflexors Has a Significant Contribution to Walking Speed in People Who Can Walk Independently After Stroke: An Observational Study

Objective: To investigate the relationship between the strength of muscles of the affected lower limb and walking speed after stroke. Design: A cross-sectional observational study. Setting: University laboratory. Participants: Stroke survivors (N=60; mean age +/- SD, 69 +/- 11y) 1 to 6 years poststroke, able to walk 10m independently without aids. Interventions: Not applicable. Main Outcome Measures: Maximum isometric strength of 12 muscle groups (hip flexors/extensors, adductors/abductors, internal/external rotators, knee flexors/extensors, ankle dorsiflexors/plantarflexors, invertors/evertors) of the affected lower limb was measured using hand-held dynamometry. Comfortable walking speed was measured using the ten-meter walk test. Results: Univariate analysis revealed that strength of the hip flexors (r=.35, P=.01), hip extensors (r=.29, P=.03), hip internal rotators (r=.30, P=.02), hip adductors (r=.29, P=.03), knee extensors (r=.27, P=.03), knee flexors (r=.30, P=.02), ankle dorsiflexors (r=.50, P=.00), ankle plantarflexors (r=.29, P=.03), and ankle evertors (r=.33, P=.01) were all positively associated with walking speed. Multivariate analysis (n=58) revealed that the combined strength of the ankle dorsiflexors and the hip flexors accounted for 34% of the variance in walking speed (P<.001). The ankle dorsiflexors accounted for 31% of the variance (P<.001). Conclusions: The strength of muscle groups other than the lower limb extensors, particularly the ankle dorsiflexors, has an important role in determining walking speed after stroke. (c) 2012 by the American Congress of Rehabilitation Medicine