Self-selected step length asymmetry is not explained by energy cost minimization in individuals with chronic stroke.

Only 28 individuals with chronic stroke were enrolled and only 10 met criteria, and they had to walk unassisted, have clinically meaningful asymmetry, and be able to alter asymmetry, so results may not apply to more impaired or non-altering stroke survivors. The unimpaired control group was not age, gender, or walking-speed matched, so differences between groups cannot be attributed to stroke alone. Chronic stroke participants walked at individually selected speeds that were slower than their maximum over-ground speed, so a relationship between asymmetry and energy cost might appear at different speeds. The biofeedback task was voluntary and could be mentally challenging, and variability in step length asymmetry and metabolic rate was high, which may have reduced the ability to detect a small effect. Only step length asymmetry was tested; the study did not examine temporal, kinetic, or kinematic asymmetries, or long-term rehabilitation outcomes.

The article lists funding from the National Science Foundation and the American Heart Association. The supplied text does not provide an author conflict-of-interest declaration.

Do not conclude that making step length symmetric will improve energy economy in chronic stroke. This study measured only acute voluntary changes in step length asymmetry in 10 participants and found no metabolic difference, so it does not show that symmetry training changes energy cost or walking performance.