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This study examined the effects of resistance training combined with whey protein and leucine blends on muscular strength (1-RM), endurance (repetitions to failure [RTF]), cross-sectional area (CSA), perceived exertion (RPE), and body mass (BM). Thirty-nine men (age = 20.6 ± 1.5 yrs) were randomly assigned to 1 of 3 Groups: (a) 1 dose of 40 g of whey protein and 6.2 g of total leucine (1PRO+L, n = 13); (b) 2 doses of 20 g of whey protein and 6.2 g of total leucine per dose (2PRO+L, n = 12); or (c) placebo (PLA, n = 14). The dependent variables were assessed before and after 8 weeks of high-intensity resistance training 3 d·wk-1. Mixed factorial ANOVAs revealed significant (P < 0.001) increases in BP and LE 1-RM and RTF, VL CSA, a reduction in RPE, and no change in BM (P > 0.05), with no between Group differences. Individual analyses indicated that a greater proportion of the 1PRO+L Group exceeded the minimal important difference for LE 1-RM and RTF compared to those in the 2PRO+L and PLA Groups (P < 0.05). No other differences were observed for the individual responses. These findings indicate that 40 g of whey protein with 6.2 g of total leucine increased LE 1-RM and RTF more than 2 doses of 20 g of whey protein with 6.2 g of total leucine or PLA. [ABSTRACT FROM AUTHOR]

This study examined the effects of sustained, isometric forearm flexion tasks anchored to ratings of perceived exertion of 2 (RPE2FT) and 8 (RPE8FT) on the patterns of fatigue-induced changes in torque and neuromuscular responses, time to task failure (TTF), performance fatigability (% decline in maximal voluntary isometric contraction [MVIC]), and perceived factors that contributed to task termination. Twelve men (mean ± SD: age = 20.9 ± 2.2 yrs) performed MVICs before and after the tasks and completed post-test questionnaires (PTQ). Data were analyzed using polynomial regression analyses, dependent t-tests, Spearman's rank order correlations, and Wilcoxon signed rank tests. The RPE8FT had greater (p < 0.001) performance fatigability than the RPE2FT, despite no difference (p > 0.05) in TTF. During both tasks, there were significant (p ≤ 0.05) composite linear decreases for torque, electromyographic amplitude, and neuromuscular efficiency, and substantial individual variability in the neuromuscular responses. There were no significant (p > 0.05) associations among the perceived factors and TTF or performance fatigability. Thus, there were RPE-specific differences in performance fatigability, but not TTF or the composite patterns of changes in torque and neuromuscular responses. In addition, in most cases, the individual neuromuscular, but not torque, patterns of responses were RPE-specific. Furthermore, the perceived factors assessed by the PTQ were not related to TTF or performance fatigability. [ABSTRACT FROM AUTHOR]

This study examined the torque and neuromuscular responses following sustained, isometric, forearm flexion tasks anchored to 2 ratings of perceived exertion (RPE). Nine men (mean ± SD: age = 21.0 ± 2.4 years; height = 179.5 ± 5.1 cm; body mass = 79.6 ± 11.4 kg) completed maximal voluntary isometric contractions (MVIC) before and after sustained, isometric, forearm flexion tasks to failure anchored to RPE = 2 and RPE = 8. The amplitude (AMP) and mean power frequency (MPF) of the electromyographic (EMG) signal were recorded from the biceps brachii. Normalized torque was divided by normalized EMG AMP to calculate neuromuscular efficiency (NME). A dependent t-test was used to assess the mean difference for time to task failure (TTF). Repeated-measures analysis of variances was used to compare mean differences for MVIC and normalized neuromuscular parameters. There was no significant difference in TTF between RPE = 2 and RPE = 8 (p = 0.713). The MVIC decreased from pretest to posttest at RPE = 2 (p = 0.009) and RPE = 8 (p = 0.003), and posttest MVIC at RPE = 8 was less than that at RPE = 2 (p < 0.001). In addition, NME decreased from pretest to posttest (p = 0.008). There was no change in normalized EMG AMP or EMG MPF (p > 0.05). The current findings indicated that torque responses were intensity specific, but TTF and neuromuscular responses were not. Furthermore, normalized EMG AMP and EMG MPF remained unchanged but NME decreased, likely due to peripheral fatigue and excitation-contraction coupling failure. Thus, this study provides information regarding the neuromuscular responses and mechanisms of fatigue associated with tasks anchored to RPE, which adds to the foundational understanding of the relationship between resistance exercise and the perception of fatigue. [ABSTRACT FROM AUTHOR]

Type 1 collagen is an abundant structural protein with importance to the skin, eyes, bones, ligaments, tendons, and muscles. Shilajit supplementation has been shown to increase gene expression of collagen synthesis, however, it is unclear if increased gene expression translates to increases in circulating levels. Therefore, the purpose of the present study was to examine the effects of 8 weeks of daily supplementation with 500 mg·d-1 and 1000 mg·d-1 of Shilajit versus placebo on serum pro-c1α1, a biomarker of type 1 collagen synthesis. Thirty-five recreationally trained men (mean ± S D: age = 21.1 ± 1.8 yrs; body mass = 80.7 ± 12.4 kg; height = 180.9 ± 6.7 cm) volunteered to participate in this study. Mixed factorial and one-way ANOVAs were used to analyze mean differences between groups, with follow-up t-tests when necessary. Individual subject responses were assessed using the minimal clinically important difference and Chi-squared tests. There were significant (Low dose: p = 0.008, d = 1.2; High dose: p = 0.007, d = 1.3) increases in serum pro-c1α1 from pre- (Low dose: 42.5 ± 12.4 ng·mL-1; High dose: 42.7 ± 12.7 ng·mL-1) to post-supplementation (Low dose: 82.3 ± 46.5 ng·mL-1; High dose: 113.1 ± 78.7 ng·mL-1) for the low and high dose groups, however, no change (p > 0.05) for the placebo group. A greater proportion (p = 0.03) of subjects exhibited increases in pro-c1α1 that exceeded the minimal clinically important difference in the high dose Shilajit group (75%) compared to the placebo group (30%), but no differences (p = 0.06) between the low dose Shilajit group (69%) and placebo. In conclusion, 8 weeks of Shilajit supplementation with 500 and 1000 mg·d-1 increased type 1 collagen synthesis as indicated by serum levels of pro-c1α1. [ABSTRACT FROM AUTHOR]