CAVANAGH, PETER R. and KEITH R. WILLIAMS. The effect of stride length variation on oxygen uptake during distance running. Med. Sci. Sports Exercise, Vol. 14, No. 1, pp. 30-35, 1982. Ten recreational runners (mean VO2max) 64.7 ml.kg-1.min-1) underwent a 5-d acclimation period to treadmill running at a 7 min.mile-1 pace (3.83 m.s-1) for 30 min each day. During these runs their freely chosen stride lengths were determined and expressed as a percentage of leg length (%LL). On two subsequent testing days stride length was systematically varied over a range of +/- 20% LL about the freely chosen value. O2 uptake was determined by the Douglas Bag method. All subjects exhibited a stride length at which O2 uptake was minimized, although the individual profiles varied considerably. The mean increases in VO2 were 2.6 and 3.4 ml.kg-1.min-1 at the short-and long-stride length extremes, respectively. During unrestricted running deviations from optimal stride length caused a mean increase in VO2 of 0.2 ml.kg-1.min-1. The relatively efficient running patterns used by the subjects during unrestricted running indicate either an adaption to the chosen stride length through training or a successful process of energy optimization.
(C)1982The American College of Sports Medicine