EFFECT OF STEP LENGTH OPTIMIZATION ON THE AEROBIC DEMAND OF RUNNING

To assess whether distance runners displaying uneconomical freely chos en step lengths (FCSL) could be trained to shift FCSL toward a more op timal setting, six males and three females who exhibited uneconomical FCSL [mean optimal step length (OSL) = -9.81% of leg length from FCSL; mean change in oxygen uptake (Vo(2)) (FCSL - OSL) = 1.46 ml.kg(-1).mi n(-1)] comprised an experimental group that completed 15 treadmill ses sions (30 min/day, 5 days/wk, 3 wk) of OSL training at individually de termined running velocities (2.87-3.74 m/s). Training sessions feature d alternating Ei-min periods of combined audio and visual feedback mat ching OSL and no feedback. A control group of three subjects with unec onomical FCSL (2 males, 1 female) performed 3 wk of treadmill running without feedback. The extent of step length optimization was evaluated by comparing pre- and posttraining differences between FCSL and OSL a nd between pre- and posttraining Vo(2). Compared with the control grou p, the experimental group demonstrated a significantly (P less than or equal to 0.05) greater relative shift in FCSL toward OSL and a marked reduction in FCSL Go,. Taken together, these results suggest that sho rt-term audiovisual feedback training can be effective in optimizing s tep length and producing a decrease in aerobic demand among distance r unners exhibiting uneconomical FCSL.