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Gregory S. Rash and Robert Shapiro

Twelve collegiate football quarterbacks were videotaped while performing drop back passes. The video images were digitized using a Peak Performance system, and three-dimensional (3-D) kinematic and kinetic data were calculated from the 3-D coordinate data using standard analytical procedures. The sequential timing of peak shoulder torques in the delivery for the football throw was peak abduction torque prior to the point of maximum shoulder external rotation (MER), peak internal rotation torque just after MER, and peak horizontal adduction torque just prior to release. As anticipated, large medial deviation torques at the elbow were found in the acceleration phase. However, in many cases the quarterbacks demonstrated larger elbow lateral deviation torques during the follow-through than found in the acceleration phase. This paper will describe these and other kinetic results and the kinematic findings observed during the football pass.

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Gregory S. Rash, Joey Garrett, and Michelle Voisin

Six of the top 10 American female 100-meter hurdlers were analyzed for biomechanical factors. This was accomplished by using three 16mm Locam high-speed cameras operating at 100/fps. The first five strides out of the blocks and the strides prior to, over, and after the fourth hurdle were analyzed for kinematic parameters. Stride lengths, support times, and nonsupport times were measured out of the blocks and about the fourth hurdle. Additional information concerning the knee angle of the lead leg at ground contact and the distance between the whole body center of gravity (WBCG) and the center of gravity (CG) of the lead leg’s foot at ground contact were also analyzed about the fourth hurdle. Generally, the women who were in the air the shortest amount of time for the first two strides out of the blocks obtained the greatest velocity in the first five strides. Also, the results of this study indicate that it may not be a question of needing to flex the knee of the lead leg coming off the hurdle to decrease horizontal braking, but the ability to get the WBCG over or in front of the CG of the lead leg foot.