Abstract:

EFFECT OF POST ACTIVATION POTENTIATION ON WEIGHTLIFTING PERFORMANCE. INTRODUCTION: Post activation potentiation (PAP) has been shown to increase kinetic profiles of athletic movements following ballistic or high intensity resistance exercises. The elicitation of PAP is heavily dependent on the biomechanical similarity of the conditioning stimuli to the movement which is to be potentiated. While PAP has been heavily investigated within the context of sprinting and jumping, a lack of information currently exists on the effects of PAP on the kinetics and kinematics of the clean. PURPOSE: The primary aim of this study was to examine the acute performance enhancing effects of a single supramaximal clean pull performed at 120% of clean and jerk (CJ) one repetition maximum (1RM) on clean performance at 90% 1RM. METHODS: Eight (n = 8) ranked collegiate level male and female weightlifters (Mean ± SD; Age: 25.8 ± 6.1 years; Height: 1.69 ± 0.97 m; Mass: 68.1 ± 10.9 kg) volunteered to participate in this study. A control session was used to identify a baseline measure of clean performance conducted at 90% of predetermined 1RM CJ. The experimental condition required participants to perform a single clean pull at 120% of CJ 1RM followed by three minutes recovery, prior to executing three cleans with one-minute recovery between repetitions. All lifts were performed on a dual force plate set up (Kistler 9286AA and BA, Winterhur, Switzerland), synchronised with a 3D motion capture system (CODA motion capture, Charnwood dynamics, Rothley, UK) to simultaneously record barbell and vertical ground reaction force (vGRF) data. All statistical analyses were performed utilizing SPSS 24.0 (IBM Corp, Armonk, NY). Reliability was quantified for six independent kinetic and kinematic variables using the coefficient of variation (CV) and interclass correlation coefficient (ICC). A paired samples t-test was performed to evaluate the differences that may exist between independent variables between the two conditions (Control vs PAP). The criterion for statistical significance was set at an alpha-level of p < 0.05. The magnitude of change was also quantified between independent variables using Cohen’s d effect sizes, with 95% confidence intervals (CI). Individual subject analysis was calculated using percentage change of the average result from the three trials performed at 90% for each condition (control vs experimental). RESULTS: All variables demonstrated good reliability except for the unweighting vertical impulse which showed poor reliability (CV = -22.45, ICC = 0.67, [-0.26 – 0.95]). The paired samples t-test indicated no statistical significance between the control and PAP condition across variables. Magnitude of change between the control and PAP condition were trivial to moderate (ES = 0.14 to -0.67, [-1.27 to 1.12]), displaying both positive and negative effects. Further analysis on individual percentage change within the six kinetic and kinematic variables demonstrated values, both positive and negative, ranging from -13% to 27%. CONCLUSION: The results demonstrate that PAP on kinetic and kinematic measures, during the clean are subject specific, and therefore may negatively affect some and not others. This is evidenced through the lack of statistical significance found between the control and experimental condition across all variables (p = 0.14 – 0.80) but is highlighted when percentage change is considered for each individual. PRACTICAL APPLICATION: The results indicate that utilising a supramaximal clean pull of 120% 3 minutes prior to performing a clean at 90% of 1RM will likely elicit a positive response for some and not others. Given that the current protocol had little effect on the group, it is suggested that individual analysis of PAP on kinetic and kinematic indices related to weightlifting is conducted in response to load, time and rest period. Identifying a potentiating stimulus for an individual within weightlifting may increase the likelihood of greater accessibility of force, thus increasing the chances of lifting a greater load.