This doctoral research investigates the energetic and mechanical demands of human locomotion under variable speed conditions, focusing particularly on walk-run-walk transitions, a topic still underexplored despite its relevance for understanding movement efficiency. Locomotion types such as walking and running are classically distinguished by their biomechanical models—the inverted pendulum for walking and the mass-spring system for running—with each model exhibiting contrasting energy recovery mechanisms based on the interaction of kinetic and potential energy phases. While walking optimises recovery through phase opposition, running, governed by elastic dynamics and phase synchrony, leads to a dramatic drop in recovery values. The transition between these locomotion modes involves a sudden mechanical shift, posing a potential increase in metabolic cost, yet this hypothesis had not been thoroughly quantified under non-constant velocity conditions. This study, carried out at the Universidad de la República (Uruguay) by Leonardo Lagos under the direction of Carlo Massimo Biancardi and Renata Luísa Bona, sought to determine whether accelerative and decelerative motion protocols around the individual's natural transition speed differed significantly from locomotion at constant speeds in terms of mechanical, electromyographic, and metabolic parameters. Laboratory experiments measured gait mechanics and physiological responses during these transitions, revealing distinct patterns in muscle synergy activation and energy expenditure. Additionally, comparisons of metabolic costs between laboratory and field conditions, guided by auditory feedback, provided insights into the ecological validity of experimental protocols. The findings contribute valuable evidence on the complex interplay between biomechanical models during transitional gaits, emphasizing that transitions may entail unique energetic and neuromuscular demands, with implications for biomechanics, rehabilitation, and athletic performance.
Lagos, L. (2023) Estudio de parámetros metabólicos, mecánicos y electromiográficos en la locomoción humana a velocidad variable y en transiciones marcha-carrera-marcha. PhD thesis. Universidad de la República, Uruguay.
