Effect of vertical loading on energy cost and kinematics of running in trained male subjects

Lacour. Effect of vertical loading on energy cost and kine-matics of running in trained male subjects. J. Appl. Physiol. 79(6): 2078-2085, 1995.-This investigation examined, in a group of 10 trained male runners, the effect of vertical loading during level treadmill running at a velocity of 5 m/s. The net energy cost of running (C,), the external work of the center of mass of the body (W,,; both expressed in J **kg- ’ l m-l), and the eccentric-to-concentric ratio (EC&on) of integrated electromyographic activity for the vastus lateralis (VL) and gastrocnemius lateralis muscles were measured. It was ob-served that Wext and EcclCon for the VL could explain a large part of the interindividual variations in C,. This result rein-forces the hypothesis that EccKon could be a good index of effectiveness in the stretch-shortening cycle. When the sub-jects ran with a vertical load of 9.3 % of their body mass, C