Association between walking and strength of lower limbs after chronic stroke

Certain muscle groups strength directly influence walking speed (WS), and the lower strength of the paretic side is significantly associated with lower WS of individuals after stroke. Studies that have investigated the association between the average of lower limb strength and the WS in individuals are scarce. Therefore, it is important to determine whether the strength could explain walking performance due to some muscle weakness could be compensated by the strength of others, mainly because all muscles act in group, not isolated. Objective: To investigate the association between WS and lower limbs muscle strength, and to identify whether an individual muscle group or the average strength of lower limb would best predict WS and walking speed reserve (WSR) in individuals with stroke. Methods: Sixty-four community-dwelling individuals with chronic stroke have their maximum isometric strength (hip flexors/extensors/abductors, knee flexors/extensors, and ankle dorsiflexors/plantarflexors) and self-selected and fast WS (10m walk test) measured. WSR was considered as the difference between the fast and self-selected speed. Results: Average strength of the paretic limb accounted for 19% and 20% of the variance in self-selected and fast WS, respectively. Plantarflexor strength of the paretic, knee and hip flexors of the non-paretic side explained alone 27% of the WSR scores and plantarflexor strength of the paretic side alone explained 15%.Conclusion: Average muscle strength of the paretic side contributed to self-selected and fast WS. Plantarflexor strength of the paretic side, knee and hip flexors of the non-paretic side contributed with the WSR of chronic stroke individuals.