Walking at non-constant speeds: mechanical work, pendular transduction, and energy congruity

Although almost half of all walking bouts in urban environments consist of less than 12 consecutive steps and several day-to-day gait activities contain transient gait responses, in most studies gait analysis is performed at steady-state. This study aimed to analyze external (W-ext) and internal mechanical work (W-int), pendulum-like mechanics, and elastic energy usage during constant and non-constant speeds. The mechanical work, pendular transduction, and energy congruity (an estimate of storage and release of elastic energy) during walking were computed using two force platforms. We found that during accelerating gait (+NCS) energy recovery is maintained, besides extra W-ext(+), for decelerating gait (-NCS) poor energy recovery was counterbalanced by W-ext(-) and C% predominance. We report an increase in elastic energy usage with speed (4-11%). Both W-ext(-) and %C suggests that elastic energy usage is higher at faster speeds and related to -NCS (approximate to 20% of elastic energy usage). This study was the first to show evidences of elastic energy usage during constant and non-constant speeds.