ECSS Paris 2023: CP-PN03
INTRODUCTION: To acutely enhance appearance and thus performance, bodybuilders implement carbohydrate (CHO) loading protocols in the week before the competition (known as peak week [PW]) to increase muscle size through the supercompensation of muscle glycogen. While the use of such strategy is seemingly prevalent, experimental designs in the context of bodybuilders are lacking, whereby the only existing trial is limited. Thus, the aim of this study was to assess the effect of an ecologically valid bodybuilding CHO-loading protocol on anthropometric measures. METHODS: Four dieting, resistance-trained males who met the inclusion criteria of ∑8 skinfolds (SF) ≤48mm (range: 34.5-45mm) participated in this randomised crossover design. This criterion was used to replicate the very low body fat levels of male bodybuilders during PW. Participants were also dieting for ≥8 weeks to represent the physiological conditions of bodybuilders during competition preparation. Each experimental period, separated by a 9-day wash-out, consisted of data collection on days 1, 4, and 5 which correspond to baseline, post-depletion, and post-loading phases of the protocol, respectively. During depletion, participants followed a standardised training regime and diet (2.2-2.6g/kg protein, 1-2g/kg CHO, 0.5g/kg fat relative to body mass [BM]) representative of the practices of bodybuilders during PW. This diet was maintained on day 4 with the addition of placebo (PLA) or CHO shakes which contained 9g/kg CHO for the post-loading data collection on day 5. Outcomes comprised of BM, SF, and ∑5 ultrasound muscle thickness (MT) which were obtained at each data collection in the morning at the same time (±1hr) after an overnight fast. Descriptive data at the group level from each day was used to assess changes. RESULTS: From baseline, BM (CHO: 76 to 75.5kg; PLA: 75.4 to 75.1kg), SF (CHO: 38.9 to 37.6cm; PLA: 38.8 to 38.8mm), and MT (CHO: 23.9 to 23.7mm; PLA: 24.3 to 24.1mm) mostly decreased following depletion in both conditions. After loading, all outcomes increased in the CHO condition (BM: 76.1kg, SF: 38mm, MT: 24.4cm) but not in PLA (BM: 74.7kg, SF: 38.6mm MT: 24.1cm) from post-depletion. However, these changes were not as pronounced in comparison to the baseline in both conditions. CONCLUSION: The implementation of a bodybuilding CHO-loading protocol may not meaningfully change BM, SF, and MT following the ingestion of 10-11g/kg of CHO in a day. While small group level changes seemingly favour CHO-loading, it is difficult to interpret these differences as large enough to exceed potential measurement error and daily biological fluctuations, and thus may not represent a meaningful change. Based on the preliminary findings, it can be interpreted that it may not be worthwhile for competitors to implement such a drastic protocol. However, outcomes such as change in visual appearance need to be quantified to fully elucidate the effects of the protocol on bodybuilding performance.
Read CV Kai HomerECSS Paris 2023: CP-PN03
INTRODUCTION: This pilot randomized controlled trial aimed to investigate the effects of time-restricted eating (TRE), aerobic exercise, and their combination on fat mass and waist circumference in females with obesity. Additionally, the study aimed to determine whether the combination of TRE and aerobic exercise produces superior changes in body composition compared to each intervention alone. METHODS: A total of 48 female participants with obesity were randomly assigned to one of four intervention groups: (1) TRE group (≤8-hour daily eating window, with ad libitum energy intake), (2) aerobic exercise group (three moderate-intensity exercise sessions per week), (3) combination group (TRE plus aerobic exercise), or (4) control group. The interventions were conducted over a 12-week period in free-living settings. Fat mass and waist circumference were measured at baseline and after the intervention. RESULTS: Of the 48 participants who underwent randomization, 47 completed the 12-week intervention. After the intervention, fat mass and waist circumference decreased in the aerobic exercise, TRE, and combination groups, but there were no significant differences between the groups. However, participants in the combination group showed a statistically significant reduction in fat mass from 25.07 ± 2.31 kg to 23.33 ± 2.31 kg compared to the control group (p=0.047). In terms of waist circumference, both the aerobic exercise group (-6.02 cm; 95% CI -0.01 to -12.03) and the combination group (-6.50 cm; 95% CI -0.64 to -12.40) showed significant decreases compared to the control group (p=0.049 and p=0.021, respectively). CONCLUSION: This pilot randomized controlled trial suggests that both TRE and aerobic exercise interventions are effective in reducing fat mass and waist circumference in females with obesity. Moreover, the combination of TRE and aerobic exercise appears to have an additive effect on fat loss. Further research with larger sample sizes and longer intervention durations is warranted to confirm these findings and explore the impact on fat mass and waist circumference.
Read CV ZIHAN DAIECSS Paris 2023: CP-PN03
INTRODUCTION: Improving body composition by increasing muscle mass and decreasing fat mass is a common approach for eliciting positive health outcomes and augmenting athletic performance. Many people aiming at modifying body composition combine dietary strategies with regular exercise. We sought to explore the effects of four weeks of time-restricted eating (TRE) vs. regular diet, combined with endurance or resistance training, on body composition of trained young males. METHODS: The order of dieting was randomized and counterbalanced, and participants served as their own controls. As in one previous study, a two-week washout period (no specific diet or exercise) separated both conditions. The experimental design consisted of two dietary interventions: (1) four weeks of TRE, in which 100% of energy intake was restricted to a time window of 8-h each day, and (2) four weeks of regular diet (non-TRE), in which 100% of energy intake were freely distributed throughout the 24-h day. Height and body mass were used to calculate body mass index (BMI). Each participant was scanned with dual-energy X-ray absorptiometry at baseline and post-intervention. The participants followed structured training routines during each dietary intervention, with a frequency of 3 times/wk (endurance group: 10 km of continuous heavy-outdoor running + 1 severe running bout of 1000 m; resistance group: 4 sets of maximum repetitions at 85% one-repetition maximum - five multi-joint dynamic full body exercise routine). One-way repeated measures ANOVA was used to determine baseline differences between conditions on body composition variables. ANCOVAs were computed for the change in each variable over time, using baseline measures as covariates. RESULTS: There were no significant differences between groups or conditions at baseline. The results from ANCOVA indicate that, in both groups, TRE elicited a greater magnitude of decrease in BMI than the non-TRE condition (F=4.2, p=0.048; ES=0.128). Moreover, we found a significant group main effect on fat-free mass (FFM) (p=0.024) indicating that, regardless of diet, the resistance training group exhibited greater magnitude of change in FFM at post-intervention time point. No other variable (i.e. fat-free mass, absolute or relative fat mass) was affected by either intervention over time. CONCLUSION: In conclusion, four weeks of TRE can be used with endurance running or resistance training to elicit BMI reductions in trained young males. However, when compared to that seen with a regular diet, TRE does not offer any additional benefit for potentiating meaningful changes in body composition during the course of 4 weeks of endurance or resistance training.
Read CV Joana M. CorreiaECSS Paris 2023: CP-PN03