Magnitude of Postactivation Potentiation response in elite rowers
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Postactivation Potentiation (PAP) has been proposed as a means by which to achieve greater physiological and mechanical power through the manipulation of previous contractile work. However, there is a lack of applied PAP studies conducted with elite, Olympic level athletes, particularly using endurance-trained populations. Whilst the proposed mechanisms responsible for PAP are increasingly complex, and further mediated according to the properties of the conditioning stimulus, it appears that PAP effects are greatest amongst highly-trained strength and power subjects. Highly endurance-trained elite rowers, a sport that necessitates superior levels of developed strength, power and muscular endurance, presented a unique opportunity to examine PAP in an applied setting within a specialised population. Therefore the primary aim of this thesis was to examine the magnitude of change in PAP in an elite endurance population. A repeated measures crossover design (3-sets of 3-repetitions of back squat at 80% of 1RM, 5-minutes rest) was utilised in order to examine the PAP response, measured via countermovement jump (CMJ) performance, to the experimental condition. Nineteen elite level male rowing athletes from the Rowing New Zealand Summer squad volunteered to participate in the study. The magnitude of observed changes in PAP ranged from unclear to small (positive). Specifically, small increases in mean power (W) (+5.7%, effect size (ES) = 0.36, 90%CI 0.13-0.59, p=0.01) and mean velocity (m.s-1) (+3.3%, ES=0.39, 90%CI 0.11-0.67, p=0.03) were observed. Unclear responses were observed for peak power (W), peak velocity (m.s-1), mean and peak force (N), rate of force development (RFD) (N.s-1) and jump height (cm). Furthermore, and in keeping with findings of other studies, responses exhibited a high level of individual variation. Test-retest reliability and measurement precision of the observed variables were strong (ICC≥0.78, CV≤6.5%). These results establish the ability of highly trained endurance athletes to engender small PAP responses to the given experimental condition. The study was unable to determine which physiological mechanisms were responsible for the observed PAP response. The magnitude of PAP response to differing conditioning stimuli, and the relevance of these findings to practical applications, requires further consideration. Whilst the results may have potential implications for the use of varying training methods and monitoring of fatigue, further research is required to greater understand the effect of variable manipulation in this specific population.