Reduced Ambulatory Activity After Stroke: The Role of Balance, Gait, and Cardiovascular Fitness

Abstract

Michael KM, Allen JK, Macko RF. Reduced ambulatory activity after stroke: the role of balance, gait, and cardiovascular fitness. Objectives To determine ambulatory activity in a sample of community-dwelling people with chronic hemiparetic stroke and to examine whether deficits in balance and gait and cardiovascular and metabolic fitness are key determinants of ambulatory activity levels. Design Descriptive correlational. Setting Home and community. Participants Twenty-eight men and 22 women (N=50) over the age 45 years with more than 6 months of hemiparetic gait after ischemic stroke. Interventions Not applicable. Main Outcome Measures Ambulatory activity (total daily step activity), mobility deficit severity (Berg Balance Scale [BBS] scores, timed 10-m walks), and cardiovascular fitness (energy costs of hemiparetic gait, peak exercise capacity [V o 2peak]). Results Mean ambulatory activity profiles were extremely low (2837 steps/d vs reported 5000–6000 steps/d in sedentary older adults). Ambulatory activity levels were strongly associated with BBS scores ( r=.581, P<.001) and self-selected floor walking velocity ( r=.554, P<.001). Participants also had profound cardiovascular deconditioning (mean V o 2peak, 11.7±2.8mL·kg −1·min −1). The energy costs of hemiparetic gait were high (8.7±1.7mL·kg −1·min −1), representing 76% of physiologic fitness reserve. Although the relationships of economy of gait and V o 2peak to ambulatory activity was not statistically significant, both the V o 2peak and the physiologic fitness reserve, as expressed by fractional utilization, were strongly related to balance ( r=.374, P=.02; r=−.430, P< .01, respectively.) The BBS predicted 30% of the variance in ambulatory activity. Conclusions Ambulatory activity levels and cardiovascular fitness in patients with chronic stroke are extremely low. Mobility deficits, particularly in balance, are associated with low ambulatory activity. Balance-related inactivity may be an important factor in deconditioning. Further studies are needed to better understand whether task-oriented exercise enhances balance and whether increases in daily ambulatory activity yield improved cardiovascular fitness in chronic stroke survivors.