Strength and aerobic requirements during stair ambulation in persons with chronic stroke and healthy adults

Objective: To estimate the cost of stair ascent and descent in relation to a measured standard of strength and metabolic (aerobic) capacities in persons with chronic stroke compared with healthy adults.

Design: Descriptive cross-sectional study.

Setting: Motion analysis laboratory.

Participants: Persons with stroke (n=10) and sex- and age-matched older adults (n=10).

Intervention: Not applicable.

Main outcome measures: Lower limb peak joint moments generated during stair walking, expressed as a percentage of the respective isokinetic peak torque, provided an estimate of the relative strength cost. The oxygen consumed during stair walking as a percentage of the maximum oxygen consumption estimated from a submaximal cycle ergometer test reflected the relative aerobic cost of stair ambulation.

Results: During ascent, plantarflexor strength cost was highest on the affected side (stroke) compared with the less affected side and control subjects. The costs associated with the knee extensors were highest in stroke (both sides) for both ascent and descent, and similarly the costs were highest for the less affected and affected plantarflexors during descent. No differences were detected between the affected and less affected sides. The oxygen consumed when ambulating 1 flight of stairs was comparable between groups, but the relative aerobic cost of stair ascent and descent was higher in stroke survivors because of their lower aerobic capacity.

Conclusions: To our knowledge, this is the first study to compare the relative costs of stair ambulation in people with stroke and healthy controls. The higher strength and aerobic costs associated with stair negotiation in stroke resulting primarily from reduced strength and aerobic capacities, respectively, may limit mobility.