Author(s): SELVAMOORTHY, R., DONALD, N., HUNTER, A.M., MACGREGOR, L.J., Institution: UNIVERSITY OF STIRLING, Country: UNITED KINGDOM, Abstract-ID: 799

INTRODUCTION:
Flywheels are ideal for warm-ups as they are transportable and produce an appropriate stimulus to enhance jump performance. Certain sports, such as swimming and athletics, have a transition period lasting at least 20 minutes between the warm-up and the competition, rendering most warm-up practices diminished as any warm-up-related enhancements typically last 3-9 minutes. Adding a small body weight exercise re-warmup at regular intervals could prolong the warmup-related enhancements time decay. Enhanced mechanical power can be mediated by increased central drive from the brain or enhanced muscle contractility of the target muscles.
METHODS:
Eight males and eight females underwent a control and an intervention session separated by at least seven days. In both sessions, the participants underwent a lunge complex warm-up, followed by one set of flywheel squats of three reps of high inertia followed immediately by three reps of low inertia; in the intervention session, the participants performed a lunge complex re-warmup every 3-minutes post the flywheel squat, while in the control session, the participants remained rested in the supine position. Measurements were taken at baseline, after the lunge complex warm-up, after the flywheel squat, and then every 9 minutes after the flywheel squat until a total of 27 minutes was reached. At every measurement time point, the participants performed three countermovement jumps on a force plate, and the maximum height (cm) obtained was used for analysis: motor evoked potential (MEP(V)) and cortical silent period (cSP (ms)) were measured using TMS; peak evoked torque (Nm) was measured by delivering a 2ms wide pulse at 280V (10-150mA) to the femoral nerve while the participants sat on an isokinetic dynamometer, with their hip and knee angle at 90° to the ground. Furthermore, the participants vastus lateralis (VL) and rectus femoris (RF) muscle normalised response speed (Vrn (mm/s/mm)) were measured using tensiomyography. A one-way ANOVA (time x condition) was performed separately for all the dependent variables for males and females.
RESULTS:
There was a significant increase in Vrn in the RF in males for the intervention session compared to the control session (P = 0.02), while in females, there was a significant change in Vrn for time (P = 0.006). There were no changes in jump height (P > 0.05), TMS MEP (P > 0.05), TMS cSP (P>0.05), evoked torque (P > 0.05), normalised response speed (P > 0.05) for any of the conditions at any time point in both males and females.
CONCLUSION:
A flywheel-based warm-up alone or accompanied by a lunge complex re-warmup every 3 minutes can produce changes to individual muscle contractility, with no changes to jump performance and central drive or global knee extensor contractility. The findings of this study are essential for practitioners who may be using similar warm-up protocols that may be sub-optimal for enhancing jump performance in their athletes.