ACUTE STUDY: CHANGES IN SPRINT KINEMATICS AND KINETICS WITH UPPER BODY LOADING AND LOWER BODY LOADING USING EXOGEN® EXOSKELETONS
Simperingham and Cronin (9)
To compare the effects of different WR placements on maximal sprinting performance using a non-motorised treadmill.
WR of 5% BM was attached to either the upper and lower body (Figure 11). Eight sport science students performed four sets of two 6 second sprints on a non-motorised treadmill.
- For the same relative load (5% BM), greater changes with lower body WR were found compared to upper:
- the time to cover distances above 10 m and the peak velocities achieved during AP and MVP were significantly slower by -2.3 to -4.2 % with lower WR
- lower WR resulted in a – 2.9 % reduction in step frequency during acceleration
- Lower body WR loading resulted in increased vertical GRF (up to 5%), while altering peak velocity, contact time and step frequency (< 5 %).
- Upper body WR did not alter velocity but reduced FT up to 15% and consequently decreased vertical GRF relative to BM (up to 6 %).
- 7 out of 8 participants perceived improved unloaded sprint performance following four sprints with WR.
- Lower body loading rather than upper body loading at 5% BM appears to provide a more effective vertical stimulus to increase eccentric strength and muscle stiffness.
- For athletes wanting to overload the start and acceleration phase of a sprint, lower body loading may be used to increase GRF and step variables.
- A series of sprints with WR may be an effective pre-conditioning stimulus to induce a perception of potentiated unloaded sprint acceleration performance.