Strength of the respiratory and lower limb muscles and functional capacity in chronic stroke survivors with different physical activity levels

ABSTRACT

BACKGROUND: The assessment of strength and its relationships with functional capacity could contribute to more specific and effective disability management of stroke survivors. OBJECTIVE: To compare and investigate associations between measures of strength and functional capacity of 98 chronic stroke survivors, stratified into three groups, according to their physical activity levels. METHOD: The physical activity levels were classified as impaired, moderately active, and active, based on their Human Activity Profile (HAP) scores. Strength was assessed by the maximal inspiratory (MIP) and expiratory (MEP) pressures and by the residual deficits (RDs) of work of the lower limb and trunk muscles, whereas functional capacity was evaluated by the distance covered during the six-minute walking test (6MWT). RESULTS: One-way analyses of variance revealed significant differences between the groups, except between the active and moderately active groups regarding the RDS of the hip and knee flexors/extensors and ankle dorsiflexors (2.91<F<8.62; 0.001<p<0.01). Differences between the groups were found for the 6MWT (F=10.75; p<0.001), but no differences were found for the MIP and MEP measures (0.92<F<2.13; 0.13<p<0.40). Significant, negative, and fair correlations were observed between the RDS of the hip and knee muscles and the 6MWT (0.30<r<-0.43; p<0.01) and the HAP (-0.28<r<-0.41; p<0.01). Moderate to good correlations were found between the 6MWT and the HAP (r=0.50; p<0.0001). There were no significant correlations between measures of respiratory strength and any of the investigated variables (-0.11<r<0.12; 0.26<p<0.56). CONCLUSIONS: Lower strength deficits and higher functional capacity were associated with higher physical activity levels. However, the moderately active and active groups demonstrated similar strength deficits. .