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The aim of this study was to compare barbell velocities at different intensities and estimated 1-RM with actual 1-RM measured with different measuring tools in bench presses and squats. Fourteen resistance-trained athletes (eight men, six women, age 28.1 ± 7.5 years, body mass 78.1 ± 12.2 kg, body height 1.73 ± 0.09 m) performed bench presses and squats at five loads varying from 45 to 85% of one repetition maximum (1-RM), together with 1-RM testing, while measuring mean, mean propulsive, and peak barbell velocity with six different commercially used inertial measurement units (IMUs) and linear encoder software systems attached to the barbell. The 1-RM was also estimated based upon the load–velocity regression, which was compared with the actual 1-RM in the bench press and squat exercises. The main findings were that GymAware revealed the highest reliability along with minimal bias, while Musclelab and Vmaxpro showed moderate reliability with some variability at higher loads. Speed4lifts and PUSH band indicated greater variability, specifically at higher intensities. Furthermore, in relation to the second aim of the study, significant discrepancies were found between actual and estimated 1-RM values, with Speed4lifts and Musclelab notably underestimating 1-RM. These findings underscore the importance of selecting reliable tools for accurate velocity-based training and load prescription.

The demand for safe and efficacious botanical formulations to increase muscle mass, strength, and stamina is increasing among athletes and the general population. The nutraceutical supplements of medicinal plant origin exert minimal health concern. This randomized, double-blind, placebo-controlled study was aimed to evaluate the ergogenic potential of a proprietary, standardized formulation (LI12542F6) of flower head and stem bark extracts. Forty male participants 18-40 years of age were assigned to receive either a placebo ( = 20) or 650 mg/day LI12542F6 ( = 20) for 56 days. All participants performed a fixed set of resistance exercises during the intervention. The primary endpoint was the change from baseline muscle strength, assessed by one-repetition maximum (1-RM) bench and leg presses, and handgrip strength. The secondary endpoints included cable pull-down repetitions, time to exhaustion on a treadmill, mid-upper arm circumference (MUAC), body composition using dual-energy x-ray absorptiometry (DEXA), and free testosterone and cortisol levels in serum. Fifty-six days supplementation of LI12542F6 significantly improved baseline bench press ( < 0.0001), leg press ( < 0.0001), handgrip strength ( < 0.0006), number of repetitions ( < 0.0001), and time to exhaustion ( < 0.0008), compared to placebo. Post-trial, the LI12542F6 group also showed significantly increased MUAC and improved body composition and serum hormone levels. The participants' hematology, clinical chemistry, and vital signs were within the normal range. No adverse events were observed. This study demonstrates that LI12542F6 supplementation significantly increases muscle strength and size and improves endurance in healthy men. Also, LI12542F6 is well-tolerated by the participants.

Purpose: Athletes often use dietary supplements to enhance their exercise performance. This study investigated the additive effects of Phyllanthus amarus (EB-PA) and whey protein isolate (WPI), compared to WPI alone or placebo on skeletal muscle strength in active males. Participants and Methods: A total of 121 healthy male participants, aged 20 to 35 years and engaged in moderate physical activity, were randomly assigned to one of three groups: placebo group (Microcrystalline cellulose [MCC] capsule and maltodextrin sachet), WPI group (WPI [40 g] and MCC capsule], or EB-PA + WPI group (WPI [40 g] and EB-PA capsule [500 mg]). All participants completed resistance training twice weekly for 30 days. The primary outcome was muscle strength, assessed by 1-repetition maximum (1-RM) for the upper and lower body. Secondary outcomes included muscle endurance, muscle flexibility, muscle mass, and grip strength. Results: At the end of study, combining the EB-PA with WPI showed significantly improved in both upper (18.02%) and lower body (17.62%) 1-RM strength compared to WPI [upper (9.24%) and lower body (9.02%)] as well as placebo [upper (4.39%) and lower body (3.39%)]. The EB-PA + WPI group achieved a 22.89% significant increase in muscle endurance compared to 11.47% increase in the WPI group. Additionally, statistically significant enhancements were observed in muscle flexibility and grip strength in the EB-PA + WPI group versus the other groups (p<0.05). Conclusion: Combination of EB-PA and WPI after 30 days significantly enhanced muscle strength, endurance, flexibility, and grip strength in active males. This suggests the EB-PA enhances muscle strengthening effect of protein supplements. EB-PA was safe throughout the study. Keywords: phyllanthus amarus, protein, muscle strength, flexibility, 1-RM

Background: the aim of the study was to develop and validate a specific perception velocity scale for the Back Squat exercise to discriminate the velocity of each repetition during a set. Methods: 31 resistance trained participants completed 3 evaluation sessions, consisting of 3 blinded loads (light, medium, heavy). For each repetition, barbell mean velocity (Vr) was measured with a linear position transducer while perceived velocity (Vp) was reported using the Squat Perception of Velocity (PV) Scale. Results: Pearson correlation coefficients (r) showed very high values for each intensity in the 3 different days (range r = 0.73–0.83) and practically perfect correlation for all loads (range r = 0.97–0.98). The simple linear regression analysis between Vp and Vr revealed values ranging from R2 = 0.53 to R2 = 0.69 in the 3 intensities and values ranging from R2 = 0.95 to R2 = 0.97 considering all loads. The reliability (ICC2.1, SEM) of Vp was tested for light (0.85, 0.03), medium (0.90, 0.03) and heavy loads (0.86, 0.03) and for all loads (0.99, 0.11). The delta score (ds = Vp − Vr) showed higher accuracy of the PV at heavy loads. Conclusions: these results show that the PV Squat Scale is a valid and reliable tool that can be used to accurately quantify exercise intensity.

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.

The effects of 9 weeks of amorphous calcium carbonate (ACC) supplementation (1000 mg/day) and resistance exercise training (RT) on one repetition maximum (1-RM) values were tested. Thirty-one women (33.1 ± 7.3 y) were randomly assigned into a supplement (ACC, n = 14) or a placebo (PL, n = 17) group. On day 1 and following 9 weeks of intervention, the participants underwent anthropometric measurements and filled out a food frequency questionnaire (FFQ) and sports injuries questionnaires. 1-RM values were measured for the back squat and bench press exercises. All the participants significantly (p = 0.01) improved their mean back squat and bench press 1-RM values (time effect). While no between-group difference was observed in the bench press 1-RM values, the ACC groups’ mean post-pre bench press 1-RM differences (Δ1-RM) were significantly higher than in the PL group, expressed in kg (p = 0.049), per body mass (p = 0.042), or per lean body mass (p = 0.035). No significant interaction was observed for time X group effect (p = 0.421). No differences (within- or between-groups) were observed in the anthropometric values or in the questionnaires’ results. ACC supplementation revealed an ergogenic effect by augmenting the improvement of maximum amount generated force, which can possibly be attributed to the calcium and/or the carbonate components.

Limited research exists comparing sex differences in muscular power. The primary purpose of this research was to determine if differences exist in power and velocity in the conventional deadlift (CDL). A secondary purpose was to examine the relationship among power, velocity, strength, and fat free mass (FFM). Eighteen strength trained athletes with ≥1 year CDL experience (women: n = 9, 29 ± 2 years, 162.3 ± 1.8 cm, 62 ± 2.4 kg, 23.3 ± 3.2 % body fat (%BF); men: n = 9, 29 ± 3 years, 175.6 ± 1.8 cm, 85.5 ± 1.4 kg, 14.8 ± 2.4 %BF), and ≥1.5 one repetition maximum (1-RM) CDL: body mass (BM) ratio (women: 1.6 ± 0.1 1-RM CDL: BM; men: 2.3 ± 0.1 1-RM CDL: BM), performed baseline (body composition, 1-RM CDL) and experimental sessions, in which velocity and power were measured at 30%, 60%, and 90% 1-RM. Repeated measures ANOVA and bivariate correlations were conducted. Men produced higher absolute average and peak power across all loads, but higher average velocity at only 30% 1-RM. When normalized to FFM, men produced higher peak and average power; however, women produced higher peak and average velocities across all loads. FFM and 1-RM were correlated with power. Greater power observed in men is driven by larger muscle mass, which contributes to greater strength.

Objective Various nutritional strategies are adopted for athletes to maintain and to improve performance during the competition season. Betaine may enhance performance during a competitive season by increasing the testosterone to cortisol ratio and reducing systemic inflammation. The aim of this study was to investigate the effect of betaine supplementation on the bio-motor abilities in young professional soccer players. Methods Twenty-nine young professional soccer players (age, 15.5±0.3 years) were matched by position and randomly assigned to one of two groups for 14 weeks: betaine (BG, 2 g/day; n =14) or placebo (PG n =15). Diet was standardized by a nutritionist, and measures of muscular power (countermovement jump: CMJ), change of direction: modified 5-0-5), acceleration (10 m sprint), sprint performance (30 m sprint time: SpT), muscular strength (leg press and bench press one repetition maximum: 1-RM), repeated sprint ability (running-based anaerobic sprint test: RAST), and aerobic capacity (30-15 intermittent fitness test) were assessed in the pre (P1), mid (P2) and post (P3) season over the course of 5 days. All subjects participated in one soccer match and five training sessions per week. Results Significant ( p < 0.05) group x time interactions were found for maximal oxygen uptake (VO 2max ), anaerobic peak power, and muscular strength favoring BG at P2 and P3 compared to P1. There were meaningful ( p < 0.05) group x time interactions for CMJ, SpT, and peak power during the RAST that favored the BG. Conclusions 14-week of betaine supplementation increased predicted 1-RM, VO 2max , and repeated sprint ability performance in youth professional soccer players. Betaine supplementation seems to be a useful nutritional strategy to improve and to maintain performance during a competitive soccer season.

The purpose of this review was to examine how different relative loads in weight training can improve acceleration over 10 m from a standing or flying start. A systematic review of the literature was undertaken using the following databases: PubMed, MedLine, Google Scholar, and SPORTDiscus. Studies were eligible if they met the following criteria: (1) participants were at least 15 years or older and healthy and injury free, (2) the study included at least one exercise for the lower body with a strength training frequency of at least once a week and included a training period of at least four weeks, and (3) interventions with clear pre- and post-test results on 10 m sprint or 10 m flying start are stated. Non-English-language articles were excluded. Percent change and between-group effect size (ES) were calculated to compare the effects of different training interventions. Forty-nine studies met the inclusion criteria. The results were categorized into four groups: (1) explosive weight training with light loads at 30–60% of 1-RM, (2) explosive weight training with moderate loads at 60–85% of 1-RM, (3) maximal weight training at 85–100% of 1-RM, and (4) hypertrophy training at 60–85% of 1-RM. At 10 m, all methods of weight training demonstrated improvements, and maximal weight training demonstrated the highest results with a large ES, while other approaches varied from very small to moderate ES. Weight training showed little progression with a significantly lower effect on flying start across all training methods, except for one group that trained power cleans (hypertrophy) where progress was large. To improve acceleration over the first 10 m, this review demonstrated maximal weight training as the preferred training method. For athletes with a pre-existing high level of strength, it could be more appropriate to use explosive training with light loads or a combination of the two. To a lesser extent, acceleration from a flying start could be improved using both training methods as well.

The purpose of this study was to investigate the differences between weightlifters and track and field throwers in terms of the rate of force development (RFD), lean mass, muscle architecture and one-repetition maximum (1-RM) muscle strength. Sixteen elite male athletes (eight weightlifters and eight track and field throwers) participated in the study. Measurements were performed one week after the annual national championships and included anthropometry, body composition analysis (dual X-ray absorptiometry), vastus lateralis (VL) muscle architecture (ultrasonography), countermovement jump (CMJ), leg press isometric RFD and 1-RM strength in snatch and back squat. RFD was similar between groups (p > 0.05), although RFD relative to lean mass was higher for weightlifters (p < 0.05). Throwers had a higher trunk lean mass compared to weightlifters (p = 0.007). Weightlifters had a longer VL fascicle length compared to throwers (p = 0.037). Performances in CMJ height, CMJ power relative to body mass and 1-RM strength were higher for the weightlifters (p < 0.05). Lean body mass index was correlated with back squat (r = 0.667) and snatch (r = 0.498). VL fascicle length was significantly correlated with snatch (r = 0.631) and back squat (r = 0.718). These results suggest that weightlifters may produce greater power outputs and 1-RM strength than track and field throwers, which may be associated with longer VL fascicle length.