Orthopedics · Medical Literature
The effects of different velocity loss thresholds on post-activation performance enhancement in basketball players.
Abstract
This study investigated the effects of different velocity loss (VL) thresholds during squat exercise at 80% of one-repetition maximum (1RM) on post-activation performance enhancement (PAPE) in basketball players. Nineteen male collegiate basketball players completed three familiarization sessions and four randomized crossover experimental sessions: control (passive rest), 5% VL, 10% VL, and 20% VL. Countermovement jump height (JH), peak power output (PPO), and reactive strength index modified (RSIm) were measured pre-test and at 3-min and 8-min post-squat. Linear mixed-effects models (LMMs) evaluated the effects of time, condition, and mean-centered relative strength on the outcome variables and repetition counts. To identify responders who exhibited meaningful improvements in jump height, the smallest worthwhile change (SWC) was calculated. At the group level, no significant condition × time interactions or main effects of condition were observed for JH, PPO, or RSIm (p > 0.05), indicating no uniform PAPE effect across protocols. Furthermore, no statistically significant strength × time × condition interaction effects were observed. Repetition counts did not differ between the 5% and 10% VL conditions but were significantly lower in both conditions compared to the 20% VL condition (p < 0.01). Individual analysis showed the 20% VL condition yielded the highest number of responders (n = 11; 58%). Squat protocols using 5-20% VL at 80% 1RM did not produce significant group-level CMJ performance improvements, suggesting that a comprehensive warm-up may create a performance ceiling. Furthermore, these responses were not moderated by relative strength. However, the high inter-individual variability and responder rates at higher VL thresholds highlight the importance of individualized PAPE programming.
Clinical relevance
Do different velocity loss (VL) thresholds (5%, 10%, or 20%) during a back squat at 80% of one-repetition maximum produce differential post-activation performance enhancement (PAPE) effects on countermovement jump height, peak power output, and reactive strength index modified in male collegiate basketball players, compared with passive rest? __SNAPSHOT__ {"studyDesign":"Randomized crossover experimental study (within-subjects design with four conditions)","setting":"Not reported (collegiate sports science or strength and conditioning laboratory setting implied; country not specified in abstract)","sampleSize":"n = 19 male collegiate basketball players (all participants completing all four conditions)","population":"Male collegiate basketball players who completed three familiarization sessions prior to experimental trials; specific inclusion/exclusion criteria, age, body mass, training experience, and relative strength values not reported in the abstract","intervention":"Back squat at 80% 1RM performed to three distinct velocity loss thresholds: 5% VL, 10% VL, and 20% VL (each as a separate experimental condition)","comparator":"Control condition: passive rest (no conditioning activity)","primaryOutcome":"Countermovement jump height (JH); secondary outcomes included peak power output (PPO) and reactive strength index modified (RSIm), assessed pre-test and at 3-min and 8-min post-squat","followUp":"Acute; post-intervention measurements at 3 minutes and 8 minutes within each session; number of days between crossover sessions not reported in the abstract","fundingSource":"Not reported"}
Key findings
At the group level, no statistically significant condition × time interactions and no main effects of condition were observed for any of the three outcome measures — countermovement jump height (JH), peak power output (PPO), or reactive strength index modified (RSIm) — across any VL protocol compared with passive rest (p > 0.05 for all). No statistically significant three-way strength × time × condition interaction effects were detected, indicating that baseline relative strength did not meaningfully moderate PAPE responses across VL thresholds. Repetition counts did not differ significantly across conditions (remainder of abstract truncated; specific repetition counts, descriptive statistics, confidence intervals, and effect sizes for these outcomes are not reported in the available abstract excerpt). To characterize individual responsiveness, the smallest worthwhile change (SWC) was applied to identify 'responders' who exhibited meaningful improvements in jump height at the individual level; specific responder proportions and magnitudes are not reported in the available abstract. No absolute or relative effect sizes, confidence intervals, NNT, or NNH values are reported in the available abstract excerpt.
Practice implications
This study found no uniform group-level PAPE effect from any of the three velocity loss thresholds (5%, 10%, or 20%) during squat exercise at 80% 1RM in male collegiate basketball players at either a 3-minute or 8-minute post-exercise window. The absence of significant condition × time interactions suggests that systematically varying the degree of intra-set fatigue, as operationalized through VL thresholds, does not produce a consistent acute jump performance enhancement at the group level in this population. The analysis of baseline relative strength as a moderating variable did not reveal a significant interaction, though the limited sample (n = 19) may have been underpowered to detect clinically meaningful moderation effects. The application of the SWC criterion to identify individual responders is methodologically important, as it acknowledges that group-level null findings may obscure clinically meaningful responses in subsets of athletes; however, responder data are not fully available from the abstract. These findings apply specifically to male collegiate basketball players; female athletes, elite-level players, and those with substantially different strength profiles were not represented. Findings should not be extrapolated to other exercises, loads, rest intervals, or athletic populations. Importantly, only the abstract was available for review, limiting full appraisal of methods, complete results, and the responder analysis. __LIMITATIONS__ Small sample size (n = 19), which substantially limits statistical power to detect moderate-to-small condition × time interaction effects and strength moderation effects.,Only male collegiate basketball players studied; results cannot be generalized to female athletes, youth players, professional-level athletes, or other sports.,Abstract truncated: complete repetition count data, individual responder proportions, effect sizes, and confidence intervals are not available for full appraisal.,Crossover design with only three familiarization sessions; order effects, carry-over fatigue between sessions, and adequacy of washout periods cannot be assessed from the abstract.,Passive rest comparator limits ability to distinguish VL-protocol effects from any general warm-up or non-specific movement priming effect.,Post-exercise measurement time points (3 and 8 min) were fixed; it is unknown whether an alternative recovery window might produce different results.,Relative strength was assessed as a continuous moderator using mean-centering in linear mixed-effects models; the specific range of relative strength values in this sample is not reported, limiting inference about which strength levels might benefit.,Funding source not reported; potential conflicts of interest cannot be evaluated.,Outcomes (JH, PPO, RSIm) are performance surrogates; direct implications for in-game basketball performance or injury risk are not established.,Only the abstract was available; full methodological detail, complete statistical output, and discussion of practical significance could not be reviewed. __BOTTOM_LINE_CATEGORY__ promising_but_preliminary __BOTTOM_LINE__ No velocity loss threshold (5%, 10%, or 20%) during a squat at 80% 1RM produced a statistically significant group-level PAPE effect on countermovement jump height, peak power output, or reactive strength index modified in male collegiate basketball players at 3 or 8 minutes post-exercise. Individual responder analyses using the smallest worthwhile change were conducted but full results are unavailable from the abstract. Clinicians and strength and conditioning professionals should not assume that VL-threshold-based squat protocols reliably generate acute jump performance enhancement in this population without confirmation from the complete study data and ideally from independent replication.