Do Muscle Mass and Body Fat Differ Between Elite and Amateur Natural Physique Athletes on Competition Day? A Preliminary, Cross-Sectional, Anthropometric Study.

ABSTRACT: González-Cano, H, Martín-Olmedo, JJ, Baz-Valle, E, Contreras, C, Schoenfeld, BJ, García-Ramos, A, Jiménez-Martínez, P, and Alix-Fages, C. Do muscle mass and body fat differ between elite and amateur natural physique athletes on competition day? A preliminary, cross-sectional, anthropometric study. J Strength Cond Res 38(5): 951-956, 2024-Natural physique athletes strive to achieve low body fat levels while promoting muscle mass hypertrophy for competition day. This study aimed to compare the anthropometric characteristics of natural amateur (AMA) and professional (PRO) World Natural Bodybuilding Federation (WNBF) competitors. Eleven male natural physique athletes (6 PRO and 5 AMA; age = 24.8 ± 2.3 years) underwent a comprehensive anthropometric evaluation following the International Society for the Advancement of Kinanthropometry protocol within a 24-hour time frame surrounding the competition. The 5-component fractionation method was used to obtain the body composition profile of the muscle, adipose, bone, skin, and residual tissues. Five physique athletes exceeded the 5.2 cutoff point of muscle-to-bone ratio (MBR) for natural athletes. Professional physique athletes were older than AMA physique athletes (p = 0.05), and they also presented larger thigh girths (p = 0.005) and bone mass (p = 0.019) compared with AMA physique athletes. Although no statistically significant between-group differences were observed in body mass, height, or body fat levels, PRO physique athletes exhibited a higher body mass index (BMI; AMA: 24.45 ± 0.12; PRO: 25.52 ± 1.01; p = 0.048), lean body mass (LBM; AMA: 64.49 ± 2.35; PRO: 69.80 ± 3.78; p = 0.024), fat-free mass (FFM; AMA: 71.23 ± 3.21; PRO: 76.52 ± 4.31; p = 0.05), LBM index (LBMI; AMA: 20.65 ± 0.52; PRO: 21.74 ± 0.85; p = 0.034), and fat-free mass index index (FFMI; AMA: 22.80 ± 0.22; PRO: 23.83 ± 0.90; p = 0.037) compared with AMA physique athletes. These findings highlight the unique characteristics and anthropometric differences between PRO and AMA natural physique athletes on competition day, emphasizing the significance of age, thigh girth, bone mass, BMI, LBM, FFM, and FFMI in distinguishing these 2 groups. Based on our findings, the established boundaries for muscle mass in natural physique athletes, based on FFMI and MBR, warrant reconsideration.

Time-restricted eating and supervised exercise for improving hepatic steatosis and cardiometabolic health in adults with obesity: protocol for the TEMPUS randomised controlled trial.

INTRODUCTION: Metabolic dysfunction-associated steatotic liver disease is a major public health problem considering its high prevalence and its strong association with extrahepatic diseases. Implementing strategies based on an intermittent fasting approach and supervised exercise may mitigate the risks. This study aims to investigate the effects of a 12-week time-restricted eating (TRE) intervention combined with a supervised exercise intervention, compared with TRE or supervised exercise alone and with a usual-care control group, on hepatic fat (primary outcome) and cardiometabolic health (secondary outcomes) in adults with obesity. METHODS AND ANALYSIS: An anticipated 184 adults with obesity (50% women) will be recruited from Granada (south of Spain) for this parallel-group, randomised controlled trial (TEMPUS). Participants will be randomly designated to usual care, TRE alone, supervised exercise alone or TRE combined with supervised exercise, using a parallel design with a 1:1:1:1 allocation ratio. The TRE and TRE combined with supervised exercise groups will select an 8-hour eating window before the intervention and will maintain it over the intervention. The exercise alone and TRE combined with exercise groups will perform 24 sessions (2 sessions per week+walking intervention) of supervised exercise combining resistance and aerobic high-intensity interval training. All participants will receive nutritional counselling throughout the intervention. The primary outcome is change from baseline to 12 weeks in hepatic fat; secondary outcomes include measures of cardiometabolic health. ETHICS AND DISSEMINATION: This study was approved by Granada Provincial Research Ethics Committee (CEI Granada-0365-N-23). All participants will be asked to provide written informed consent. The findings will be disseminated in scientific journals and at international scientific conferences. TRIAL REGISTRATION NUMBER: NCT05897073.

Efficacy of different 8 h time-restricted eating schedules on visceral adipose tissue and cardiometabolic health: A study protocol.

BACKGROUND AND AIMS: To investigate the efficacy and feasibility of three different 8 h time-restricted eating (TRE) schedules (i.e., early, late, and self-selected) compared to each other and to a usual-care (UC) intervention on visceral adipose tissue (VAT) and cardiometabolic health in men and women. METHODS AND RESULTS: Anticipated 208 adults (50% women) aged 30-60 years, with overweight/obesity (25 ≤ BMI<40 kg/m2) and with mild metabolic impairments will be recruited for this parallel-group, multicenter randomized controlled trial. Participants will be randomly allocated (1:1:1:1) to one of four groups for 12 weeks: UC, early TRE, late TRE or self-selected TRE. The UC group will maintain their habitual eating window and receive, as well as the TRE groups, healthy lifestyle education for weight management. The early TRE group will start eating not later than 10:00, and the late TRE group not before 13:00. The self-selected TRE group will select an 8 h eating window before the intervention and maintain it over the intervention. The primary outcome is changes in VAT, whereas secondary outcomes include body composition and cardiometabolic risk factors. CONCLUSION: This study will determine whether the timing of the eating window during TRE impacts its efficacy on VAT, body composition and cardiometabolic risk factors and provide insights about its feasibility.

Effects of phenylcapsaicin on aerobic capacity and physiological parameters in active young males: a randomized, triple-blinded, placebo-controlled, crossover trial.

Objective: Phenylcapsaicin (PC) is a new capsaicin analog which has exhibited a higher bioavailability. This sudy assessed the effects of a low dose (LD) of 0.625 mg and a high dose (HD) of 2.5 mg of PC on aerobic capacity, substrate oxidation, energy metabolism and exercise physiological variables in young males. Materials and methods: Seventeen active males (age = 24.7 ± 6.0 years) enrolled to this randomized, triple-blinded, placebo-controlled, crossover trial. Participants attended the laboratory on 4 sessions separated by 72-96 h. A submaximal exercise test [to determine maximal fat oxidation (MFO) and the intensity at MFO (FATmax)] followed by a maximal incremental test (to determine VO2max) were performed in a preliminary session. The subsequent sessions only differed in the supplement ingested [LD, HD or placebo (PLA)] and consisted of a steady-state test (60 min at FATmax) followed by a maximal incremental test. Energy metabolism, substrate oxidation, heart rate, general (gRPE) and quadriceps (RPEquad) rate of perceived exertion, skin temperature and thermal perception were tested. Results: Clavicle thermal perception was lower in HD compared to PLA and LD (p = 0.04) across time. HD reduced maximum heart rate in comparison to PLA and LD (p = 0.03). LD reported higher general RPE (RPEg) values during the steady-state test compared to PLA and HD across time (p = 0.02). HD and LD elicited higher peak of fat oxidation during the steady-state test compared with PLA (p = 0.05). Intra-test analyses revealed significant differences for fat oxidation (FATox) in favor of HD and LD compared to PLA (p = 0.002 and 0.002, respectively), and for carbohydrate oxidation (CHOox) (p = 0.05) and respiratory exchange ratio (RER) (p = 0.03) for PLA. In the incremental test, only general RPE at 60% of the maximal intensity (W) differed favoring HD (p ≤ 0.05). Conclusion: Therefore, PC may contribute to increase aerobic capacity through the improvement of fat oxidation, maximum heart rate and perceptual responses during exercise.