Loaded countermovement jump exercise using elastic bands potentiates subsequent jump performance following a comprehensive task-specific warm-up

INTRODUCTION: Performing voluntary muscle actions using elastic bands (EB) to precondition the muscle in combination with free-weight (FW) resistance, can alter the loading characteristics of these actions to impose a greater mechanical stimulus and increase subsequent performance [1]. These actions can precondition the neuromuscular system, however the limited warm-up commonly utilised in these studies [2] could invalidate the potentiation often reported, with the impact of loaded countermovement jumps using elastic bands on subsequent jump performance requiring further investigation. Therefore, the aim of the present study was to examine the influence of EB resistance following a comprehensive warm-up on subsequent jump (CMJ) performance. METHODS: Fifteen active men (age = 21.7 ± 1.1 y, height = 1.8 ± 0.1 m, mass = 77.6 ± 2.6 kg) volunteered to take part in the study. On two separate occasions, following a comprehensive warm-up consisting of 5 min cycling, 10 continuous unloaded squats, 5 continuous CMJs at ~70% of maximum, then maximal jumps were performed every 30 s until 3 jumps were within 3% of maximum jump height, participants performed 5 repetitions of either EB- or FW-loaded CMJs at 50% 1-RM (35% of load generated from elastic resistance during EB). CMJs were then performed 30 s, 4 min, 8 min, and 12 min later with jump height and electromyograms (EMG) of the vastus lateralis (VL), vastus medialis (VM), gluteus maximus (Glut) and gastrocnemius medialis (GM) recorded. RESULTS: Compared to baseline, no significant (P ≥ 0.05) changes in CMJ height (0.3-2.7%) or EMG activity (VL = 0.6-7.1%; VM = 0.8-1.6%; Glut = 3.1-8.7%; GM = 0.6-6.4%) were observed in the FW condition. Significant increases in CMJ height (4.6-8.0%) and EMG activity for peak concentric VL (10.3-18.8%) were found at 30 s and 4 min in the EB condition; no changes in jump height (0.3-0.9%) or EMG activity (VL = 6.0-7.9%; VM = 2.1-4.4%; Glut = 3.2-5.3%; GM = 1.8-7.1%) were found at 8 min and 12 min. DISCUSSION: The lack of change in CMJ performance in the FW condition is consistent with previous research [1] and indicative that the comprehensive warm-up fully potentiated the neuromuscular system such that subsequent FW contractions provided no further improvements. However, the further improvements in CMJ height in the EB condition at 30 s and 4 min, associated with increases in peak vastus lateralis (VL) concentric EMG activity, is indicative of further potentiation on the neuromuscular system to improve jump performance. These data suggest the use of elastic resistance may provide a superior warm-up protocol for athletes to provide short-term improvements in strength and power performance. REFERENCES: 1.Mina MA, Blazevich AJ, Tsatalas T, Giakas G, Seitz LB, Kay AD. (2019). Scand J Med Sci Sports 29: 380-392. 2.Marshall et al. (2019). J Strength Cond Res. 33(6):1551-1556.