Comparative Kinematic Measures of Treadmill Running with or without Body Weight Support in Runners.

Treadmill walking and running using a supportive harness has been used as a training method to rehabilitate injured patients' walking or running gait. Comparison of full weight support (FWS) and body weight support (BWS) kinematic measures in competitive runners has received little attention. The purpose of this study was to compare selected FWS to BWS kinematic measures in healthy competitive runners. Ten male runners (age = 21.4 ± 1.5 years) with a training regimen averaging 64 km per week at 3.8 m·s(-1) participated. All participants ran three 3-minute trials. The randomized trial conditions were: FWS, 20% BWS, and 40% BWS. All conditions were videotaped with 2 cameras and a 21-point, 3-D model was generated for analysis. From the position-time data, cycle length (CL), cycle frequency (CF), time of contact (TC), hip-, knee-, ankle- range of motion in degrees (H-ROM, K-ROM, and A-ROM, respectively), and vertical displacement of the center of mass (COM) were derived and compared. With increasing support conditions, cycle length increased. Cycle frequency, hip and ankle angle ranges, and COM vertical displacement decreased (p < 0.05). However, the ankle angle range of motion varied little between 20% and 40 % BWS (p > 0.05). BWS running produced significant changes in selected kinematic measures. These changes may provide insight into runners' behavior when using BWS in training or recovery from competition. Additional investigation of BWS training affect with competitive runners would be recommended. Key PointsRunning kinematics change gradually with increasing levels of body weight support.At constant speed, center of mass vertical displacement, lower leg angular displacement, foot contact time and cycle frequency decrease significantly from FWS to 40S.Harness running can have beneficial effects in healthy runners recovering from intense bouts of exercise.