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Variable, but not free‐weight, resistance back squat exercise potentiates jump performance following a comprehensive task‐specific warm‐up
Author(s) -
Mina Minas A.,
Blazevich Anthony J.,
Tsatalas Themistoklis,
Giakas Giannis,
Seitz Laurent B.,
Kay Anthony D.
Publication year - 2019
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.13341
Subject(s) - squat , vastus medialis , concentric , ground reaction force , physical medicine and rehabilitation , kinematics , ankle , medicine , jumping , electromyography , jump , force platform , vertical jump , physical therapy , mathematics , anatomy , physics , geometry , physiology , classical mechanics , quantum mechanics
Studies examining acute, high‐speed movement performance enhancement following intense muscular contractions (frequently called “post‐activation potentiation”; PAP) often impose a limited warm‐up, compromizing external validity. In the present study, the effects on countermovement vertical jump (CMJ) performance of back squat exercises performed with or without elastic bands during warm‐up were compared. After familiarization, fifteen active men visited the laboratory on two occasions under randomized, counterbalanced experimental squat warm‐up conditions: (a) free‐weight resistance (FWR) and (b) variable resistance (VR). After completing a comprehensive task‐specific warm‐up, three maximal CMJs were performed followed by three back squat repetitions completed at 85% of 1‐RM using either FWR or VR Three CMJs were then performed 30 seconds, 4 minutes, 8 minutes, and 12 minutes later. During CMJ trials, hip, knee, and ankle joint kinematics, ground reaction force data and vastus medialis, vastus lateralis, and gluteus maximus electromyograms (EMG) were recorded simultaneously using 3D motion analysis, force platform, and EMG techniques, respectively. No change in any variable occurred after FWR ( P > 0.05). Significant increases ( P < 0.05) were detected at all time points following VR in CMJ height (5.3%‐6.5%), peak power (4.4%‐5.9%), rate of force development (12.9%‐19.1%), peak concentric knee angular velocity (3.1%‐4.1%), and mean concentric vastus lateralis EMG activity (27.5%‐33.4%). The lack of effect of the free‐weight conditioning contractions suggests that the comprehensive task‐specific warm‐up routine mitigated any further performance augmentation. However, the improved CMJ performance following the use of elastic bands is indicative that specific alterations in force‐time properties of warm‐up exercises may further improve performance.