This study was designed to investigate whether a warm-up routine that incorporates drop jumps, induces post-activation potentiation (PAP), and if so, assess the magnitude and time course of the induced PAP. Participants performed a standard warm-up that incorporated either drop jumps (plyometric protocol) or a low-paced walk (control protocol). PAP was assessed by changes in electrically-evoked isometric muscle twitches recorded throughout both protocols. The plyometric protocol increased peak twitch torque (PTT), rate of force development (RTD) and impulse significantly (by 23%, 39% and 46%, respectively) with no change in the amplitude of simultaneously-evoked M-waves, indicating that the augmented torque was due to PAP. These increases returned to baseline within 6 minutes, and PTT and RTD fell below baseline values at 11 - 16 minutes after the drop jumps. PTT, RTD and impulse decreased significantly following the standard warm-up. These results provide evidence that drop jumps induce PAP, markedly enhancing the force generating capacity of the muscle. In contrast, the standard warm-up did not potentiate, but rather reduced, the force generating capacity of the muscle. We suggest that drop jumps be incorporated into warm-up routines directly prior to athletic performance to maximize the force generating capacity of muscle.
a Human Neurophysiology Laboratory, Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada.
b Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada.
Correspondence: David F. Collins, Address: Faculty of Physical Education and Recreation, E-488 Van Vliet Centre, University of Alberta, Edmonton, Alberta Canada T6G 2H9, Phone: (780) 492-6506, Fax: (780) 492-2364, E-mail: email@example.com, Webpage: www.dfcollins.ca