Factors modulating post-activation potentiation and its effect on performance of subsequent explosive activities.
ABSTRACT Post-activation potentiation (PAP) is induced by a voluntary conditioning contraction (CC), performed typically at a maximal or near-maximal intensity, and has consistently been shown to increase both peak force and rate of force development during subsequent twitch contractions. The proposed mechanisms underlying PAP are associated with phosphorylation of myosin regulatory light chains, increased recruitment of higher order motor units, and a possible change in pennation angle. If PAP could be induced by a CC in humans, and utilized during a subsequent explosive activity (e.g. jump or sprint), it could potentially enhance mechanical power and thus performance and/or the training stimulus of that activity. However, the CC might also induce fatigue, and it is the balance between PAP and fatigue that will determine the net effect on performance of a subsequent explosive activity. The PAP-fatigue relationship is affected by several variables including CC volume and intensity, recovery period following the CC, type of CC, type of subsequent activity, and subject characteristics. These variables have not been standardized across past research, and as a result, evidence of the effects of CC on performance of subsequent explosive activities is equivocal. In order to better inform and direct future research on this topic, this article will highlight and discuss the key variables that may be responsible for the contrasting results observed in the current literature. Future research should aim to better understand the effect of different conditions on the interaction between PAP and fatigue, with an aim of establishing the specific application (if any) of PAP to sport.
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ABSTRACT: This study investigated the acute effects of a currently implemented team-sport warm-up and two alternative, high-intensity, short-duration protocols - 5 repetition maximum leg press and small-sided games. Ten male soccer players participated in a randomised, cross-over study. Participants performed a team-sport, a leg-press, or a small-sided game warm-up. Subsequent performance tests included counter-movement jump, reactive agility, and 15×20 m sprints embedded in an intermittent exercise task. Physiological measures included core temperature, blood lactate concentration, heart rate and rating of perceived exertion. Data were analysed using the effect size statistic with 90% confidence intervals, and percentage change, to determine magnitude of effects. Counter-movement jump height improved following the small-sided game (6%, ES: 0.8±0.8) and leg-press warm-up (2%, ES: 0.3±0.5), but not after the team-sport warm-up ('unclear' effect). Reactive agility improved after the small-sided game (4%, ES: 0.8±0.7) and leg-press warm-ups only (5%, ES: 1.1±0.7), when compared to baseline. Mean 20-m sprint times during the intermittent exercise task improved following the leg-press warm-up, when compared with the small-sided game (9%, ES: 0.9±0.3) and team-sport warm-ups (7%, ES: 0.6±0.6). Core temperature was lower following the leg-press warm-up compared to small-sided game (1%, ES: 0.9±0.7) and the team-sport WUs (2%, ES: 2.4±0.8). Blood lactate was highest following the small-sided game (67%, ES: 2.7±0.8) and team-sport warm-ups (66%, ES: 2.9±0.9). A leg-press and small-sided game warm-up may improve acute team-sport performance tests when compared to a traditional warm-up protocol.Journal of science and medicine in sport / Sports Medicine Australia. 09/2011; 14(6):522-8.