Adolescent runners: the effect of training shoes on running kinematics.

BACKGROUND: The modern running shoe typically features a large cushioned heel intended to dissipate the energy at heel strike to the knees and hips. The purpose of this study was to evaluate the effect that shoes have upon the running biomechanics among competitive adolescent runners. We wish to answer the question of whether running style is altered in these athletes because of footwear.
METHODS: Twelve competitive adolescent athletes were recruited from local track teams. Each ran on a treadmill in large heel trainers, track flats, and barefoot. Four different speeds were used to test each athlete. The biomechanics were assessed with a motion capture system. Stride length, heel height during posterior swing phase, and foot/ground contact were recorded.
RESULTS: Shoe type markedly altered the running biomechanics. The foot/ground contact point showed differences in terms of footwear (P<0.0001) and speed (P=0.000215). When wearing trainers, the athletes landed on their heels 69.79% of the time at all speeds (P<0.001). The heel was the first point of contact <35% of the time in the flat condition and <30% in the barefoot condition.
CONCLUSIONS: Running biomechanics are significantly altered by shoe type in competitive adolescents. Heavily heeled cushioned trainers promote a heel strike pattern, whereas track flats and barefoot promote a forefoot or midfoot strike pattern. Training in heavily cushioned trainers by the competitive runner has not been clearly shown to be detrimental to performance, but it does change the gait pattern. It is not known whether the altered biomechanics of the heavily heeled cushioned trainer may be detrimental to the adolescent runner who is still developing a running style.