Objective: The purpose of this study was to explain the internal mechanism of attention focus affecting performance of countermovement jump based on muscle synergy theory. Methods: Participants involved untrained group(N = 10) and high-level group(N = 11). Subjects performed countermovement jump with internal attention focus instruction (IF), external distal attention focus instruction (EDF), and external proximal attention focus instruction (EPF). The electromyography (EMG) signals of the dominant vastus lateralis muscle (VL), semitendinosus muscle (ST), tibial anterior muscle (TA), rectus femoris muscle (RF), and medial gastrocnemius (MG) were recorded. The non-negative matrix factorization was used to extract muscle synergy. Results: 1) Attention focus did not affect countermovement jump performance and the number of muscle synergy in the high-level group (P>0.05). 2) Attention focus instructions affected the untrained group countermovement jump (P<0.05). and EDF and EPF reduced the number of muscle synergy. 3)The Cohen’s d of EDF (0.269) was less than EPF (0.377) in untrained group. Conclusion: For the untrained people, the improved motor performance caused by attention focus resembled the adaptive changes that occur with long-term training. The reason why an EDF is superior to EPF is that the former produces more thorough changes in muscle synergy.

Introduction: Post-Activation Performance Enhancement (PAPE) is widely used to enhance explosive performance. Chain Squats (CS), as a form of variable resistance training, may offer advantages over Traditional Squats (TS) due to its load variability and neuromuscular stimulation characteristics. However, direct comparisons between the two under controlled conditions remain limited. Therefore, this study aims to compare the effects of CS and TS on PAPE to explore their different impacts on explosive strength.Methods: Eighteen male participants completed CS and TS training at 90% of their 1RM in a randomized crossover design. Countermovement Jump (CMJ) tests were conducted at baseline and at 4, 8, 12, and 16 min post-intervention to evaluate Jump Height (JH), Peak Power (PP), Peak Rate of Force Development (PRFD), and Peak Impulse (PI).Results: Both CS and TS significantly enhanced explosive performance, but CS outperformed TS in several metrics. CS showed greater improvements in JH at 4 min (P < 0.01, η² = 0.119, d = 3.69) and 8 min (P < 0.01, η² = 0.102, d = 3.49). For PP, CS also outperformed TS with larger effect sizes at the same time points. PRFD showed no significant change in either modality, but CS showed a downward trend at 12 min (P = 0.055, η² = −0.014, d = −424.16). PI peaked at 4 min in the CS group (P < 0.01, η² = 0.019, d = 6.56), significantly outperforming TS.Discussion: CS significantly outperformed TS in enhancing JH, PP, and PI during the 4-8 min post-intervention period. Compared to TS, CS is a more advantageous PAPE strategy, offering a more effective way to enhance explosive performance in athletes.

Introduction: This study investigated whether stepwise load reduction training (SLRT) yields comparable or superior effects to medium load resistance training (MLRT) on one-repetition maximum (1RM) barbell back squat, thigh circumference (TC), muscle endurance (ME), counter movement jump (CMJ) performance, and acute blood lactate (BL) levels.Methods: Thirty healthy, physically active males completed both the SLRT and MLRT protocols in a crossover design to assess acute blood lactate responses firstly. Then they were randomly assigned to SLRT, MLRT, or control (CON) groups using a sealed envelope method for an 8 weeks intervention. Anthropometric data were collected at baseline. Performance metrics (1RM, TC, ME, and CMJ) were measured at baseline, week 4, and post intervention. Blinding was not feasible due to the visible nature of interventions. To minimize bias, testing was conducted by staff not involved in training, with standardized warm-ups and protocols applied across groups. Training volume, frequency and assessment timing were matched between SLRT and MLRT. Participants were instructed to avoid other structured training, and adherence was monitored weekly. Results: The results showed that both SLRT and MLRT significantly improved 1RM and ME, but SLRT produced greater gains. No significant differences were observed in TC. Additionally, SLRT led to significantly better CMJ performance and higher BL levels at immediate, 4th, 7th, and 9th minutes post exercise. The CON group performed significantly worse on all long-term outcomes compared to both SLRT and MLRT. While both SLRT and MLRT effectively enhance muscle strength, SLRT yields superior improvements in 1RM, ME, CMJ performance, and acute BL accumulation under equivalent training volumes.Discussion: These results suggest that SLRT may offer enhanced anaerobic conditioning benefits and superior adaptation potential. However, the findings should be interpreted with consideration of certain limitations, including the homogeneity of the sample and the relatively short intervention duration.

Background: Although training load is a critical determinant of adequate training stimuli for athletes, the optimal load for power training varies across individuals, and the underlying factors contributing to this variability remain unclear.Objective: This study investigated the influence of relative strength on optimal load during the execution of the hang power clean (HPC) and hang high pull (HHP) among college athletes.Methods: A total of 30 male college athletes (mean ± standard deviation age, 21.8 ± 2.3 years) performed hang power cleans (HPCs) and hang high pulls (HHPs) on a three-dimensional force plate at loads corresponding to 45%, 65%, 80%, and 95% of their one-repetition maximum (1RM), presented in a randomized and counterbalanced order. The relationship between optimal load and relative strength was assessed using Pearson's correlation coefficient.Results: The optimal load for achieving maximum output power in the hang high pull (HPP) and hang power clean (HPC) exhibited a highly individualized characteristic.A significant positive correlation was found between athlete strength and optimal load for both the HPC (r = 0.478, P < .01) and HHP (r = 0.611, P < .001).Conclusions: A positive correlation between optimal load and the relative strength of the athlete for the HPC and the HHP indicated that as the athlete's strength increased, the load intensity should be appropriately increased to maintain efficient training stimulation to elicit maximum power for each athlete. However, this study did not examine female collegiate athletes and other athletic populations. coaches should be discreetly when applying this conclusion to these athletic groups.

Background: This systematic review and exploratory meta-analysis evaluated the effects of combined music and caffeine on psychophysiological responses during exercise. Methods: PubMed, Embase, Web of Science, and the Cochrane Library were searched from database inception to 10 June 2026. Randomized crossover studies comparing caffeine plus music with placebo plus no music, caffeine alone, or music alone were eligible. Outcomes included rating of perceived exertion (RPE), Physical Activity Enjoyment Scale (PACES), Feeling Scale (FS), and heart rate (HR). Findings were synthesized descriptively by outcome and comparator, considering study-specific effect estimates, confidence intervals, and experimental conditions. Random-effects meta-analyses were retained as secondary exploratory summaries. Because fewer than 10 independent studies were available, meta-regression and formal assessment of small-study effects were not undertaken. Results: Five crossover studies involving 88 participants were included. Study-specific RPE estimates varied from large reductions to estimates close to the null or in the opposite direction. PACES point estimates favoured the combined intervention, but their magnitudes differed substantially in comparisons with placebo plus no music and caffeine alone. Feeling Scale and heart-rate findings also varied across studies. All four primary meta-analyses showed I² values exceeding 90%, and the certainty of evidence was very low for all primary outcomes. Conclusions: The available evidence comprises five small crossover studies conducted in different populations and experimental settings. Study-specific findings suggest possible improvements in exercise enjoyment, while perceived exertion, affective valence, and heart-rate responses vary across studies. Neither the descriptive findings nor the secondary exploratory pooled estimates establish a stable, broadly applicable magnitude of intervention benefit. Given the very low certainty of evidence, no firm recommendations can be made regarding the use of caffeine combined with music across exercise populations and settings. Further adequately powered studies using clearly specified interventions and comparable outcome assessments are needed to determine which responses are reproducible and practically meaningful.

Background: Caffeine–taurine combinations are widely used in commercial sports products. Whether this combination improves exercise performance is still unclear. This study aimed to estimate the effect of caffeine–taurine co-supplementation versus placebo on exercise performance. Methods: Randomized controlled trials comparing caffeine plus taurine versus placebo were searched in PubMed, Embase, Web of Science, Cochrane Library, and related databases up to June 1, 2026. Outcomes included heart rate (HR), reaction time (RT), time to exhaustion (TTE), rating of perceived exertion (RPE), and peak/maximal anaerobic power (PP). A random-effects model was applied. Risk of bias was assessed with RoB 2.0. Results: A total of 11 randomized controlled trials involving 234 participants were included in the meta-analysis. Compared with placebo, caffeine–taurine co-supplementation was associated with improvements in time to exhaustion (SMD = 0.54, 95% CI: 0.03 to 1.05) and PP (SMD = 0.55, 95% CI: 0.21 to 0.89); an expanded secondary product-level analysis that additionally included one commercial multi-ingredient energy drink yielded a smaller estimate (SMD = 0.48, 95% CI: 0.19 to 0.78) that cannot be attributed specifically to caffeine and taurine. The pooled estimate for reaction time favored supplementation (SMD = −1.49, 95% CI: −2.78 to −0.20), but very high heterogeneity and a prediction interval crossing the null indicated that the effect was not consistent across settings, whereas no meaningful effect was observed for heart rate (WMD = −0.11, 95% CI: −5.76 to 5.53). Rating of perceived exertion was significantly reduced (SMD = −0.44, 95% CI: −0.83 to −0.04). Conclusions: Caffeine–taurine-only formulations were associated with possible benefits for selected performance outcomes, including PP. However, the evidence was derived from few, generally small studies and did not establish the independent contribution of caffeine, taurine, or their interaction. Results from commercial multi-ingredient products should be interpreted at the product level rather than as evidence of an isolated caffeine–taurine effect.