Preferred Leg Drives Seated And Bilateral Exercise In Chronic Stroke And Healthy Control

PURPOSE: The NuStep Cross Trainer (NS) approximates the bipedal and upright stepping pattern. However, it is unknown how the history of stroke may influence recumbent exercise. The purpose of this study was to examine performance outcomes on the NS in a chronic stroke condition (SC) and an age plus sex-matched control (HC).

METHODS: In order to determine cadence, each participant performed a 10 minute (min) pretest on the NS at an RPE between 12 and 16. After returning to resting HR and BP, participants then performed a 5-min exercise bout on the NS.

SUMMARY OF RESULTS: SC and HC did not differ in age (Mdn: 66 years vs. 57 years, respectively) or BMI (Stroke: M = 27.02 ± 4.57 vs. Healthy: M = 26.46 ± 4.63), p > .05. There were no differences in RPE, METS, elevation gain (ft), estimated energy cost (k/cal), average (avg.) speed (mph), avg. steps per min, or avg. bilateral power (W) between the HC (n = 19) and SC (n = 15); p > .05. However, HC produced higher total steps (M = 723.18 steps ± 137.64) compared to the SC (M = 597.67 steps ± 116.90); t(30) = 2.683, p = .012. Total step distance (miles) for the HC (mean rank = 19.74) was also greater than the SC (mean rank = 11.77), U = 62.0, z = -2.363, p = .018. However, ∆avg. pedal power (W) between the HC’s limbs (left-right) (M = -2.00 ± 3.528) was not different than SC (affected -non-affected) (M = -3.50 ± 4.852); t(29) = .997, p = .32. HC ΔROM (in) (mean rank = 17.50) did not differ from SC (mean rank = 13.62), U = 85.5, z = -1.214, p = .252. The SC did not demonstrate strength deficits on their affected side; p > .05. Bilateral comparison revealed the SC's affected side contributed less pedal power (18.08W ± 9.61) than the non-affected side (21.58 ± 10.34); p = .030. HC produced higher levels of force on their preferred right leg (M = 48.68lbs ± 10.05lbs vs. M = 44.42 ± 9.78); p < .001. No ROM difference was observed between limbs in HC or SC; p > .05.

CONCLUSION: Healthy participants covered more distance by producing more steps (not ΔROM) in the 5-minute exercise bout on the NS. The mechanical coupling of the NS seems to encourage equal ROM contribution, but the preferred leg will contribute higher avg. power in both SC (i.e., via non-affected) and the HC (i.e., via right leg). This study was supported by a grant from the National Institutes of Health, P30 AG015281. And the Michigan Center for Urban African American Aging Research.