Strength of the lower limb and trunk muscles is associated with gait speed in individuals with sub-acute stroke: a cross-sectional study.

OBJECTIVES To investigate the association between measures of strength of the lower limb and trunk muscles and gait speed and to identify the muscle group that would best predict gait speed in individuals with sub-acute stroke. METHODS Using a cross-sectional observational study design, forty-four individuals with sub-acute stroke (62 years, SD=14; 4 months, SD=1 post-stroke) were assessed. The evaluations were performed at a university laboratory, participants' homes, or community-based settings. Bilateral maximum isometric strength (hip, knee, and ankle flexors/extensors, hip abductors, trunk flexors/extensors, and trunk lateral flexors and rotators) was measured using a portable dynamometer. Comfortable and maximum gait speeds were measured using the 10-m walk test. RESULTS Weak to moderate associations were found between measures of strength of the lower limb muscles and comfortable (0.36≤r≤0.53; p<0.05) and maximum (0.37≤r≤0.59; p<0.05) gait speeds, except for the non-paretic knee flexors and comfortable gait speed (p=0.06). Weak to moderate associations were also found between measures of strength of the trunk muscles and comfortable (0.39≤r≤0.50; p<0.05) and maximum (0.39≤r≤0.61; p<0.05) gait speeds. Stepwise multiple regression analyses revealed that the non-paretic dorsiflexors and the left lateral trunk flexors explained 29% and 42% of the variance in the maximum and comfortable gait speeds, respectively. CONCLUSIONS The strength of the lower limb and trunk muscles was positively associated with comfortable and maximum gait speeds. The muscle strength of the non-paretic dorsiflexors and the left lateral trunk flexors might have a role to play in determining comfortable and maximum gait speeds of individuals with sub-acute stroke.