Oxygen uptake kinetics: associations with ambulatory activity and physical functional performance in stroke survivors.

Objective: To explore the associations amongst the on-and-off kinetics time constants, ambulatory activity outcomes, and physical functional performance in stroke survivors. Subjects: Ten stroke survivors (time since stroke: mean 7.5 years (standard deviation 8.3); gender: 4 males, 6 females) and 10 control subjects matched for age and physical activity level. Methods: Oxygen uptake kinetics (on-and-off kinetics) were measured using a submaximal exercise test with a recumbent cycle. The continuous-scale physical functional performance test was used to measure functional ability. Ambulatory activity outcomes including steps per day, number of activity bouts and length of activity bouts were measured using a Step Activity Monitor. Results and conclusion: Shorter activity bouts were significantly associated with longer off-kinetics time constants in stroke survivors (or longer time to recover from an exercise bout). Future research may test the effect of activity interventions designed to increase the length of activity bouts onkinetics outcomes and functional ability.