The aim of the current study was to investigate the effect of six weeks of strength vs. plyometric training upon change of direction (COD) performance. A total of 21 young female handball players were randomly assigned to either a strength group: (n = 11, age: 17.5 ± 2.3 years, height: 1.69 ± 0.05 m, weight: 65.8 ± 5.9 kg) training bilateral, unilateral and later squats; or a plyometric training group (n = 10, age: 17.1 ± 2.4 years, height: 1.73 ± 0.07 m, weight: 67.1 ± 9.3 kg) training drop jumps, unilateral countermovement jumps and skate-jumps. Groups were assigned after being pair-matched based upon baseline COD performance. The training modalities were matched in training impulse. A force- (180°) and velocity-oriented (45°) COD of 20 m was used to measure changes in COD performance (10 m + COD + 10 m). Total time (s) to complete the COD test was defined as the performance variable. The level of significance was set at p < 0.05. The two-way ANOVA showed no group effect upon COD performance. A significant effect was only observed for the strength training group in the last 10 m and total 20 m of the force-oriented COD (F ≥ 5.51; p ≤ 0.04; η² ≥ 0.36). Both groups improved performance in other strength- and power-related tests. It was concluded that only the strength training program was effective in developing force-oriented COD performance in the studied population, while the plyometric training program was not sufficient. Both training modalities are useful for improving performance in different strength and power tests in young female handball players.

Background: The effectiveness of strength training with free-weight vs. machine equipment is heavily debated. Thus, the purpose of this meta-analysis was to summarize the data on the effect of free-weight versus machine-based strength training on maximal strength, jump height and hypertrophy.Methods: The review was conducted in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, and the systematic search of literature was conducted up to January 1^st, 2023. Studies that directly compared free-weight vs. machine-based strength training for a minimum of 6 weeks in adults (18–60 yrs.) were included.Results: Thirteen studies (outcomes: maximal strength [n = 12], jump performance [n = 5], muscle hypertrophy [n = 5]) with a total sample of 1016 participants (789 men, 219 women) were included. Strength in free-weight tests increased significantly more with free-weight training than with machines (SMD: -0.210, CI: -0.391, -0.029,p = 0.023), while strength in machine-based tests tended to increase more with machine training than with free-weights (SMD: 0.291, CI: -0.017, 0.600,p = 0.064). However, no differences were found between modalities in direct comparison (free-weight strength vs. machine strength) for dynamic strength (SMD: 0.084, CI: -0.106, 0.273,p = 0.387), isometric strength (SMD: -0.079, CI: -0.432, 0.273,p = 0.660), countermovement jump (SMD: -0.209, CI: -0.597, 0.179,p = 0.290) and hypertrophy (SMD: -0.055, CI: -0.397, 0.287,p = 0.751).Conclusion: No differences were detected in the direct comparison of strength, jump performance and muscle hypertrophy. Current body of evidence indicates that strength changes are specific to the training modality, and the choice between free-weights and machines are down to individual preferences and goals.

Several studies have explored the effects of capsaicin and capsiate on endurance performance, with conflicting findings. This systematic review aimed to perform a meta-analysis examining the effects of capsaicin and capsiate vs. placebo on endurance performance in humans. Seven databases were searched to find eligible studies. The effects of capsaicin and capsiate on aerobic endurance (e.g., time-trials or time-to-exhaustion tests), muscular endurance (e.g., repetitions performed to muscular failure), and rating of perceived exertion (RPE) were examined in a random-effects meta-analysis. Fourteen studies (n = 183) were included in the review. Most studies provided capsaicin or capsiate in the dose of 12 mg, 45 min before exercise. In the meta-analysis for aerobic endurance, there was no significant difference between the placebo and capsaicin/capsiate conditions (Cohen’s d: 0.04; 95% confidence interval: −0.16, 0.25; p = 0.69). In subgroup meta-analyses, there were no significant differences between the placebo and capsaicin/capsiate conditions when analyzing only studies that used time-trials (p = 0.20) or time-to-exhaustion tests (p = 0.80). In the meta-analysis for muscular endurance, a significant ergogenic effect of capsaicin/capsiate was found (Cohen’s d: 0.27; 95% confidence interval: 0.10, 0.43; p = 0.002). When analyzing set-specific effects, an ergogenic effect of capsaicin/capsiate was found in set 1, set 2, and set 3 (Cohen’s d: 0.21–29). Capsaicin/capsiate ingestion reduced RPE following muscular endurance (p = 0.03) but not aerobic endurance tests (p = 0.58). In summary, capsaicin/capsiate supplementation acutely enhances muscular endurance, while the effects on aerobic endurance are less clear.

Purpose: The aim of this study was to explore the isolated and combined effects of caffeine and citrulline malate (CitMal) on jumping performance, muscular strength, muscular endurance, and pain perception in resistance-trained participants. Methods: Using a randomized and double-blind study design, 35 resistance-trained males (n = 18) and females (n = 17) completed four testing sessions following the ingestion of isolated caffeine (5 mg/kg), isolated CitMal (12 g), combined doses of caffeine and CitMal, and placebo. Supplements were ingested 60 min before performing a countermovement jump (CMJ) test (outcomes included jump height, rate of force development, peak force, and peak power), one-repetition maximum (1RM) squat and bench press, and repetitions to muscular failure in the squat and bench press with 60% of 1RM. Pain perception was evaluated following the repetitions to failure tests. The study was registered at ISRCTN (registration number: ISRCTN11694009). Results: Compared to the placebo condition, isolated caffeine ingestion and co-ingestion of caffeine and CitMal significantly enhanced strength in 1RM bench press (Cohen’s d: 0.05–0.06; 2.5–2.7%), muscular endurance in the squat (d: 0.46–0.58; 18.6–18.7%) and bench press (d: 0.48–0.64; 9.3–9.5%). However, there was no significant difference between isolated caffeine ingestion and caffeine co-ingested with CitMal, and isolated CitMal supplementation did not have an ergogenic effect in any outcome. No main effect of condition was found in the analysis for CMJ-derived variables, 1RM squat and pain perception. Conclusion: Caffeine ingestion appears to be ergogenic for muscular strength and muscular endurance, while adding CitMal does not seem to further enhance these effects.

Individual differences in the appropriate percentage of 1-RM for a given repetition range could be a result of variation in anthropometrics and/or sex. Strength endurance is the term used to describe the ability to perform a number of repetitions prior to failure (AMRAP) in sub-maximal lifts and is important in determining the appropriate load for the targeted repetition range. Earlier research investigating the association of AMRAP performance and anthropometric variables was often performed in a sample of pooled sexes or one sex only or by utilizing tests with low ecological validity. As such, this randomized cross-over study investigates the association of anthropometrics with different measures of strength (maximal and relative strength and AMRAP) in the squat and bench press for resistance-trained males (n = 19, 24.3 ± 3.5 years, 182 ± 7.3 cm, 87.1 ± 13.3 kg) and females (n = 17, 22.1 ± 3 years, 166.1 ± 3.7 cm, 65.5 ± 5.6 kg) and whether the association differs between the sexes. Participants were tested for 1-RM strength and AMRAP performance, with 60% of 1-RM in the squat and bench press. Correlational analysis revealed that for all participants, lean mass and body height were associated with 1-RM strength in the squat and bench press (0.66, p ≤ 0.01), while body height was inversely associated with AMRAP performance (r ≤ −0.36, p ≤ 0.02). Females had lower maximal and relative strength with a greater AMRAP performance. In the AMRAP squat, thigh length was inversely associated with performance in males, while fat percentage was inversely associated with performance in females. It was concluded that associations between strength performance and anthropometric variables differed for males and females in fat percentage, lean mass, and thigh length.

Barbell placement can affect squat performance around the sticking region. This study compared kinematics, kinetics, and myoelectric activity of the safety-bar squat with the high-bar, and low-bar squat around the sticking region. Six recreationally resistance-trained men (26.3 ± 3.1 years, body mass: 81 ± 7.7 kg) and eight women (22.1 ± 2.2 years, body mass: 65.7 ± 10.5 kg) performed three repetition maximums in all three squat conditions. The participants lifted the least load with the safety bar followed by the high-bar and then the low-bar squat. Greater myoelectric activity of the gluteus maximus was observed during safety-bar squats than high-bar squats. Also, larger knee extension moments were observed for the safety bar compared with low-bar squat. Men had higher myoelectric activity in the safety-bar condition for the gluteus maximus during all regions in comparison with women, and greater knee valgus at the second occurrence of peak barbell velocity. Our findings suggest that the more upright torso inclination during the safety-bar could allow greater gluteus maximus contribution to the hip extensor moment. Moreover, low-bar squats allowed the greatest loads to be lifted, followed by the high-bar and safety-bar squats, possibly due to the larger hip moments and similar knee moments compared to the other squat conditions. Therefore, when the goal is to lift the greatest load possible among recreationally trained men and women, they should first attempt squatting with a low-bar technique, and if the goal is to increase myoelectric activity in the gluteus maximus, a safety-bar squat may be the more effective than the high- bar squat.