The Effects of Post-activation Potentiation on Contractile Properties and Jump Performance in Athletes
Bibliographic record
Abstract
INTRODUCTION: Post-activation potentiation (PAP) is an acute enhancement in a muscle’s ability to generate force due to its previous contractile history. PURPOSE: To assess kettlebell swing (KB) exercise as a method of PAP and compare it to common PAP methods of tuck jump (TJ) and depth jump (DJ). METHODS: Seven varsity track athletes (age: 21±1yr; mass: 65.9±9.3kg) completed one familiarization, and three test sessions in random order. Each session consisted of a warm-up followed by evoked twitch torques (TT) measured by tibial nerve stimulation (single, doublet and triplet pulses [0.5ms, 100Hz]). After a pre-competition warm-up, participants completed a baseline counter-movement jump (CMJ) followed by the PAP exercise (2 x 5 repetitions). TT was re-assessed at 1, 2, and 3 minutes (T1,T2,T3), and CMJ at 5 and 10 min (T5,T10), post-intervention. TT parameters included peak torque (PT), rate of torque development (RTD), and half relaxation time (HRT). CMJ parameters included peak power, peak force, take-off velocity, and jump height. RESULTS: Data were normalized to baseline before conducting repeated measures ANOVA to compare exercise conditions. Condition main effects were observed for single PT at T1 (p=0.02), doublet PT at T1 (p=0.044) and T2 (p=0.049), and triplet PT at T1 (p=0.007) and T2 (p=0.034). KB had the largest change in PT (+11.1±7.8%) compared to TJ (+8.6±11.0%) and DJ (-5.5±14.1%) averaged across T1-T3 (p<0.05). Contractile properties extracted from singlets revealed KB had larger PT (+22±15%) than DJ (-4±21%) at T1 (p=.027), and a prolonged HRT (+9±17%) compared to DJ (-3±14%) at T3 (p=.031). RTD was elevated at T1 (+37.8±36.7%), T2 (+28.8±37.2%) and T3 (+25.7±28.9%; p=.026) but was not different between conditions. No condition effects were found for CMJ at T5 or T10, but effect size was large for take-off velocity (p=0.07; η2 = 0.412) at T5, where KB (+1.6±1.1%) and DJ (+2.0±3.3%) were larger than TJ (-1.6±2.7%). CONCLUSIONS: KB exhibited a tendency to potentiate evoked torque more than TJ and DJ. KB also exhibited signs of greater lower leg muscle fatigue three minutes after exercise but this did not limit CMJ performance five minutes after exercise.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".