Effects of stride length alteration on racewalking economy

This study investigated the effects of stride length (SL) manipulation on racewalking economy in 7 competitive racewalkers. Following two test sessions in which VO2 max and freely-chosen stride length (FCSL) were determined, each subject completed 6-min racewalking bouts at five randomly-ordered SL conditions (FCSL and -10%, -5%, +5%, and +10% of leg length from the FCSL) while walking at a velocity approximately equal to their 10 km training pace. Actual and predicted group mean VO2 values for the five SL conditions indicated that the subjects were most economical walking at the FCSL, with progressively higher energy costs manifested at the +5% and -5% and the +10% and -10% leg length conditions, respectively. A mean absolute difference in VO2 of 0.6 ml X kg-1 X min-1 was observed between subjects' FCSL and optimal SL. Linked with this deviation in VO2 was a mean absolute SL difference of 3.2 cm (3.6% of mean leg length). These data support the hypothesis that trained subjects select locomotion patterns that are nearly optimal in terms of the aerobic demands.