The purpose of this study was to determine the effects of an alleged aromatase and 5-α reductase inhibitor (AI) on strength, body composition, and hormonal profiles in resistance-trained men. Thirty resistance-trained men were randomly assigned in a double-blind manner to ingest 500 mg of either a placebo (PL) or AI once per day for 8 wk. Participants participated in a 4-d/wk resistance-training program for 8 wk. At Weeks 0, 4, and 8, body composition, 1-repetition-maximum (1RM) bench press and leg press, muscle endurance, anaerobic power, and hormonal profiles were assessed. Statistical analyses used a 2-way ANOVA with repeated measures for all criterion variables (p ≤ .05). Significant Group × Time interaction effects occurred over the 8-wk period for percent body fat (AI: –1.77% ± 1.52%, PL: –0.55% ± 1.72%; p = .048), total testosterone (AI: 0.97 ± 2.67 ng/ml, PL: –2.10 ± 3.75 ng/ml; p = .018), and bioavailable testosterone (AI: 1.32 ± 3.45 ng/ml, PL: –1.69 ± 3.94 ng/ml; p = .049). Significant main effects for time (p ≤ .05) were noted for bench- and leg-press 1RM, lean body mass, and estradiol. No significant changes were detected among groups for Wingate peak or mean power, total body weight, dihydrotestosterone, hemodynamic variables, or clinical safety data (p > .05). The authors concluded that 500 mg of daily AI supplementation significantly affected percent body fat, total testosterone, and bioavailable testosterone compared with a placebo in a double-blind fashion.
Colin Wilborn, Lem Taylor, Chris Poole, Cliffa Foster, Darryn Willoughby and Richard Kreider
Jay Hoffman, Nicholas Ratamess, Jie Kang, Gerald Mangine, Avery Faigenbaum and Jeffrey Stout
The effects of creatine and creatine plus β-alanine on strength, power, body composition, and endocrine changes were examined during a 10-wk resistance training program in collegiate football players. Thirty-three male subjects were randomly assigned to either a placebo (P), creatine (C), or creatine plus β-alanine (CA) group. During each testing session subjects were assessed for strength (maximum bench press and squat), power (Wingate anaerobic power test, 20-jump test), and body composition. Resting blood samples were analyzed for total testosterone, cortisol, growth hormone, IGF-1, and sex hormone binding globulin. Changes in lean body mass and percent body fat were greater (P < 0.05) in CA compared to C or P. Significantly greater strength improvements were seen in CA and C compared to P. Resting testosterone concentrations were elevated in C, however, no other significant endocrine changes were noted. Results of this study demonstrate the efficacy of creatine and creatine plus β-alanine on strength performance. Creatine plus β-alanine supplementation appeared to have the greatest effect on lean tissue accruement and body fat composition.
Thomas Rowland, Paul Vanderburgh and Lee Cunningham
Adjustment of VO2max for changes in body size is important in evaluating aerobic fitness in children. It is important, therefore, to understand the normal relationship between changes VO2max and body size during growth. Over the course of 5 years, 20 children (11 boys, 9 girls) underwent annual maximal treadmill testing to determine VO2max. The mean longitudinal allometric scaling exponent for VO2max relative to body mass (M) was 1.10 ± 0.30 in the boys and 0.78 ± 0.28 in the girls (p < .05). Respective cross-sectional values were 0.53 ± 0.08 and 0.65 ± 0.03. VO2max expressed relative to M1.0, M0.75, and M0.67 rose during the 5 years in the boys, but not the girls. Significant gender differences remained when VO2max was related to lean body mass. These findings suggest (a) factors other than body size affect the development of VO2max in children, and (b) gender differences exist in VO2max during childhood which are independent of body composition.
Jerry L. Mayhew, Michael G. Bemben and Donna M. Rohrs
The purpose of this study was to determine the relationships among the seated shot put (SSP), bench press power (BPP), and body composition in adolescent wrestlers. Seventy-five wrestlers from three high schools were tested during their preseason training. Upper body power was tested with a plate-loaded bench press machine equipped with infrared sensors attached to a digital timer. Each subject was given three trials with a constant 24.5-kg load (CLP) and with a variable load equal to 60% of body mass (VLP). Skinfolds were used to estimate body composition. The SSP was significantly related to both CLP and VLP as well as to body mass, lean body mass (LBM), and % fat. Removing the effect of body mass reduced the relationship between SSP and both CLP and VLP. Removing the effect of LBM had a slightly greater effect on the relationships between SSP and both CLP and VLP, although the correlations remained significant. Therefore it appears that the SSP is only moderately related to upper body power in adolescent wrestlers and may be greatly influenced by size and muscularity.
Eduardo Federighi Baisi Chagas, Mariana Rotta Bonfim, Bruna Camilo Turi, Nair Cristina Margarida Brondino and Henrique Luiz Monteiro
Declines in ovarian function in postmenopausal women may contribute to increase inflammatory cytokines, which can lead to chronic diseases. However, studies have shown that exercise interventions are important to manage inflammatory conditions. Thus, the objective of this study was to analyze the effect of exercise intervention on inflammatory markers among obese and postmenopausal women.
70 women composed the sample (Exercise group [EG; n = 35] and nonexercise group [nEG; n = 35]). IL-6, TNF-α, and IL-10 were the inflammatory markers analyzed. Exercise program was 20 weeks long and consisted of aerobic and neuromuscular training. Data about chronic diseases, medication use, dietary intake, body composition and biochemical variables were collected.
EG showed significant reductions in body mass index, waist circumference and body fat percentage, as well as increased lean body mass. EG showed significant reductions in TNF-α and significant interaction between group and intervention time. Reductions in IL-10 were identified only in nEG. Substantial effect of exercise intervention was observed with increased ratio of IL-10/IL-6 and IL-10/TNF-α.
Combination of aerobic exercise and resistance training was effective in reducing inflammation. Thus, implementation and maintenance of similar exercise programs can contribute to reduce chronic inflammation among obese postmenopausal women.
Dan M. Cooper, Szu-Yun Leu, Candice Taylor-Lucas, Kim Lu, Pietro Galassetti and Shlomit Radom-Aizik
Consensus has yet to be achieved on whether obesity is inexorably tied to poor fitness. We tested the hypothesis that appropriate reference of cardiopulmonary exercise testing (CPET) variables to lean body mass (LBM) would eliminate differences in fitness between high-BMI (≥ 95th percentile, n = 72, 50% female) and normal-BMI (< 85th percentile, n = 142, 49% female), otherwise-healthy children and adolescents typically seen when referencing body weight. We measured body composition with dual x-ray absorptiometry (DXA) and CPET variables from cycle ergometry using both peak values and submaximal exercise slopes (peak VO2, ΔVO2/ΔHR, ΔWR/ΔHR, ΔVO2/ΔWR, and ΔVE/ΔVCO2). In contrast to our hypothesis, referencing to LBM tended to lessen, but did not eliminate, the differences (peak VO2 [p < .004] and ΔVO2/ΔHR [p < .02]) in males and females; ΔWR/ΔHR differed between the two groups in females (p = .041) but not males (p = .1). The mean percent predicted values for all CPET variables were below 100% in the high-BMI group. The pattern of CPET abnormalities suggested a pervasive impairment of O2 delivery in the high-BMI group (ΔVO2/ΔWR was in fact highest in normal-BMI males). Tailoring lifestyle interventions to the specific fitness capabilities of each child (personalized exercise medicine) may be one of the ways to stem what has been an intractable epidemic.
Three papers which between them raise controversial issues, apply laboratory measures to sport performance, and expose gaps in knowledge were selected for commentary. The first paper (Sports Med. 2016;46:1451–1460) reviews the literature on peak V̇O2 in relation to body size and recommends that peak V̇O2 in youth is best expressed via allometric scaling of lean body mass. The second paper (Pediatr Exerc Sci. 2016;28:456–465) reports that maturity status has no effect on peak V̇O2, respiratory compensation point, or ventilatory threshold in youth soccer players once data have been allometrically normalized by lower limb muscle volume. It concludes that in future this technique should be used to compare the aerobic fitness of youth soccer players. The third paper (Eur J Appl Physiol. 2016;116:1781–1794) demonstrates that V̇O2 kinetics determined in a laboratory is related to measures associated with soccer match play and might distinguish superior performance within a group of highly trained youth players. The commentary stresses the importance of experimental rigor, emphasizes the need for appropriate scaling of physiological variables, challenges spurious correlations with health-related variables, endorses the use of a range of aerobic fitness measures, welcomes the application of laboratory data to sport performance, and identifies areas for future research.
Daniela A. Rubin, Diobel M. Castner, Hoang Pham, Jason Ng, Eric Adams and Daniel A. Judelson
During childhood, varying exercise modalities are recommended to stimulate normal growth, development, and health. This project investigated hormonal and metabolic responses triggered by a resistance exercise protocol in lean children (age: 9.3 ± 1.4 y, body fat: 18.3 ± 4.9%), obese children (age: 9.6 ± 1.3 y, body fat: 40.3 ± 5.2%) and lean adults (age: 23.3 ± 2.4 y, body fat: 12.7 ± 2.9%). The protocol consisted of stepping onto a raised platform (height = 20% of stature) while wearing a weighted vest (resistance = 50% of lean body mass). Participants completed 6 sets of 10 repetitions per leg with a 1-min rest period between sets. Blood samples were obtained at rest preexercise, immediately postexercise and 2 times throughout the 1-hr recovery to analyze possible changes in hormones and metabolites. Children-adult differences included a larger exercise-induced norepinephrine increase in adults vs. children and a decrease in glucagon in children but not adults. Similarities between adults and children were observed for GH-IGF-1 axis responses. Metabolically, children presented with lower glycolytic and increased fat metabolism after exercise than adults did. Obesity in childhood negatively influenced GH, insulin, and glucose concentrations. While adults occasionally differed from children, amount of activated lean mass, not maturation, likely drove these dissimilarities.
Radamés M.V. Medeiros, Eduardo S. Alves, Valdir A. Lemos, Paulo A. Schwingel, Andressa da Silva, Roberto Vital, Alexandre S. Vieira, Murilo M. Barreto, Edilson A. Rocha, Sergio Tufik and Marco T. de Mello
Body-composition assessments of high-performance athletes are very important for identifying physical performance potential. Although the relationship between the kinanthropometric characteristics and performance abilities of Olympic swimmers is extremely important, this subject is not completely understood for Paralympic swimmers.
To investigate the relationship between body composition and sport performance in Brazilian Paralympic swimmers 6 mo after training.
Experimental pre/posttest design.
Research laboratory and field evaluations of swimming were conducted to verify the 50-m freestyle time of each athlete.
17 Brazilian Paralympic swim team athletes (12 men, 5 women).
Main Outcome Measures:
Body-composition assessments were performed using a BOD POD, and swimming performance was assessed using the 50-m freestyle, which was performed twice: before and after 6 mo of training.
Increased lean mass and significantly reduced relative fat mass and swimming time (P < .05) were observed 6 mo after training. Furthermore, a positive correlation between body-fat percentage and performance (r = .66, P < .05) was observed, but there was no significant correlation between body density and performance (r = –.14, P > .05).
After a 6-mo training period, Paralympic swimmers presented reduced fat mass and increased lean body mass associated with performance, as measured by 50-m freestyle time. These data suggest that reduced fat-mass percentage was significantly correlated with improved swimming performance in Paralympic athletes.
Marina Fabre, Christophe Hausswirth, Eve Tiollier, Odeline Molle, Julien Louis, Alexandre Durguerian, Nathalie Neveux and Xavier Bigard
While effects of the two classes of proteins found in milk (i.e., soluble proteins, including whey, and casein) on muscle protein synthesis have been well investigated after a single bout of resistance exercise (RE), the combined effects of these two proteins on the muscle responses to resistance training (RT) have not yet been investigated. Therefore, the aim of this study was to examine the effects of protein supplementation varying by the ratio between milk soluble proteins (fast-digested protein) and casein (slow-digested protein) on the muscle to a 9-week RT program. In a double-blind protocol, 31 resistance-trained men, were assigned to 3 groups receiving a drink containing 20g of protein comprising either 100% of fast protein (FP(100), n = 10), 50% of fast and 50% of slow proteins (FP(50), n = 11) or 20% of fast protein and 80% of casein (FP(20), n = 10) at the end of training bouts. Body composition (DXA), and maximal strength in dynamic and isometric were analyzed before and after RT. Moreover, blood plasma aminoacidemia kinetic after RE was measured. The results showed a higher leucine bioavailability after ingestion of FP(100) and FP(50) drinks, when compared with FP(20) (p< .05). However, the RT-induced changes in lean body mass (p < .01), dynamic (p < .01), and isometric muscle strength (p < .05) increased similarly in all experimental groups. To conclude, compared with the FP(20) group, the higher rise in plasma amino acids following the ingestion of FP(100) and FP(50) did not lead to higher muscle long-term adaptations.