Effects of extended effortful activity on spatio-temporal parameters of gait in individuals with stroke.

Neuromuscular dyscontrol during gait following stroke may be further compromised by increased susceptibility to fatigue. Our purpose was to examine how extended effortful activity affected spatio-temporal gait parameters after stroke. The influence of sub-maximal exercise was assessed among 26 stroke survivors who performed the Six-Minute Walk Test with distance recorded every 2 min. Walking distance decreased 5.8 (S.D. 6.9) m in the second 2-min interval and another 2.3 (S.D. 9.9) m in the final 2 min (p=0.0005). Secondly, we evaluated spatio-temporal gait parameters prior to and immediately following a standardized maximal exercise test on a cycle ergometer in 36 stroke survivors. In contrast to the expected reduction in walking speed, maximal exercise led to a 5.5 (S.D. 11.5) cm/s increase in preferred gait speed (p=0.007) and a 4.5 (S.D. 7.7) steps/min increase in cadence (p=0.0004), but did not affect gait symmetry. Subsequent division of participants by preferred pedaling cadence revealed that individuals with lower preferred cadence had the greatest increase in preferred speed, cadence and paretic leg step length (p<0.01). These unexpected results suggest that potential fatigue-induced effects on gait may have been masked by immediate positive influences of movement rate on walking speed. Such activity-specific effects may have clinical applications for stroke patients and other populations with gait deviations.