Influence of Towing Force Magnitude on the Kinematics of Supramaximal Sprinting

In athletics, speed and success are often interrelated. As such, human competitiveness and ingenuity have given rise to the implementation of non-traditional methods for speed development. Among those methods is towing, a popular type of overspeed training. Athletes have been using towing for over 80 years to gain a competitive edge. However, research on towing has failed to deliver a consistent verdict regarding the mechanisms behind the method\u27s effects. At the heart of the inconsistency is the use of a universal towing force. Previous researchers have failed to standardize towing force magnitude as a function of subject characteristics and thus have failed to address the variations in technique brought about by towing force magnitude alone. Therefore, the purpose of this study will be to determine the influence of towing force magnitude on the kinematics of supramaximal sprinting. The sample population for the study will be comprised of high school and collegiate, male and female track athletes. Each subject will complete 5 sessions: one control and four experimental. All subjects will complete the control session first, which will consist of non-towed maximal trials. Thereafter, the order in which each subject completes the experimental (towed) sessions will be randomized. Each session will consist of 5-7 maximal 60m sprints from a standing start. In order to minimize the effects of fatigue, 5-7 minutes of rest will be allotted between trials and a minimum of 48 hours will be allotted between sessions. One stride-cycle will be analyzed for 3-5 trials, and the average of those trials will be included in the overall results and analysis. Kinematic data will be collected at the 35m mark in the sprint with an optical motion capture system (Vicon 460, 250fps). Four segments will be monitored: pelvis, thigh, shank, and foot. Kinematic variables of interest will be stride length (SL), stride rate (SR), horizontal velocity of the center of mass (VH), horizontal distance from the COM to the foot at touchdown (DH), flight time (FT), contact time (CT), flexion/extension (F/E) angle of the ground shank at touchdown (SAT), F/E angle of the ground hip at touchdown (HAT), F/E angle of the ground knee at touchdown (KAT), F/E angle of the ground ankle at touchdown (AAT), minimum hip F/E angle over the entire stride cycle (HAMIN), and maximum knee F/E angle over the entire stride cycle (KAMAX). To compare the effects of the various towing force magnitudes, a one-way repeated measures ANOVA will be conducted for each of the dependent variables. Significance will be accepted at p \u3c 0.05