Effect of Varying Velocity on Post-Activation Potentiation of Vertical Jump Performance

Post-activation potentiation (PAP) is a phenomenon where muscle performance is enhanced after a bout of high-intensity activity. Minimal research has been conducted on varying velocities of contraction and its effect on PAP. Discovering optimal conditions for PAP will benefit athletes in explosive sports. This study was designed to determine if different velocities of leg press at 70% of one repetition maximum (1RM) improved vertical jump performance on the Vertek® and Just Jump Mat®. It was hypothesized that faster leg press velocities would improve vertical jump more than slower leg press velocities. Twenty Hope College students (13 females, 7 males) participated in seven randomly assigned testing sessions (~ four weeks duration). The testing days consisted of a familiarization, two baseline, and four testing days. Testing days consisted of a warm up, five unilateral leg presses at 70% 1RM at assigned velocity and a six-minute rest followed by three jumps on the Just Jump Mat or Vertek. Each participant completed each velocity for each jump condition. There was no significant improvement between the pretests and subsequent velocity tests when measured by the Vertek (p=0.462) or mat (p=0.732). Mean VJ height for females for initial (16.2±1.72), fast (16.4±1.68) and slow (16.5±1.69) conditions showed no significant difference. Mean VJ height for males for initial (22.2±2.70), fast (22.0±2.81) and slow (22.4±2.86) conditions showed no significant difference. There was a highly significant correlation between the Vertek and mat results (r =0.941, p\u3c 0.01), validating the jump mat as a legitimate measure for vertical jump. Limitations include study design, participant commitment, type of participant and type of leg press routine. Future studies should include manipulation of contraction velocity, rest intervals, and percentage of 1RM along with subjects