Changes in sprint kinematics and kinetics with upper body loading and lower body loading using Exogen TM Exoskeletons: A pilot study
Journal of Australian Strength and Conditioning
Australian Strength and Conditioning Association
School of Medical and Health Sciences / Centre for Exercise and Sports Science Research
Key determinants of sprint performance include the magnitude and direction of the ground reaction force (GRF) exerted and the duration of each ground contact time (CT) (1-3). It is therefore important to understand how these kinematic and kinetic variables are acutely modified by different training techniques. One such technique is resisted sprint training where tools such as weighted vests may be used with the aim of acutely or chronically improving unloaded sprint performance (4,5). With regards to acute loading, resisted sprint training is often followed by a contrast series of unloaded sprints with the goal of achieving an acute enhancement in unloaded sprint performance due to the acute pre-conditioning effect of the loaded sprints, however this technique has not been empirically supported (6). Acute changes during sprints with a heavy vest [~11 – 22% of body mass (BM)] included significantly decreased step length, flight time (FT) and sprint times or velocities, significantly increased CT, and reduced or unchanged step frequency (7,8). Smaller relative loads of up to 1.8 kg per leg (total of approximately 4.8 % of BM) attached just above the ankle joint also resulted in a significant acute decrease in sprint velocity, which was due mainly to a reduction in stride frequency (9). Based on analysis of upper body vest loading during sprint-running on a non-motorised treadmill (NMT) it was reported that loads well in excess of 10 % of BM are required to elicit a significant acute increase in vertical GRF (Fv) compared to baseline unloaded sprinting (8). Similar kinetic analysis of maximal-effort sprinting with added external lower body loading, and a direct comparison of both the kinematic and kinetic effects of upper compared to lower body loading has not been reported in the literature...
Paper presented at the National ASCA Conference 2015