| dc.description.abstract | This study examined whether immediate (I) vs. delayed (D) protein intake following exercise influenced fractional synthesis rate (FSR) and other health/fitness markers during a Resistance Interval Program (RIPT) exercise & weight management intervention. 21 sedentary women (59.8±5 yrs, 43.7±3% body fat, 31.0±3 kg/m²) participated in a 12 week Curves Complete® program [followed an energy-reduced diet (1,500 kcal/d; 30% C, 45% P, and 25% F) while participating in circuit resistance exercise (RE) (30min; 3d/wk) and walking (10k steps, 4/d wk)]. Each ingested 15 g of protein immediately post (I) or 2 hours post (D) RE. Body composition, body mass, resting energy expenditure (REE) and FSR [determined using a deuterium oxide (²H₂O or D₂O) ingestion and muscle biopsy protocol] were examined. Data were analyzed by repeated measures MANOVA and/or ANOVA, and are presented as changes from baseline after 4, 8, and 12 wks [body composition, body mass, resting energy expenditure (REE)]; 0 and 12 weeks (FSR) for the I and D groups, respectively. Significant time effects were observed (body mass, fat mass, and body fat) yet no significant group x time effects resulted. The D group generally experienced more favorable body mass (I -2.0±1.0, -2.7±1.6, -3.6±2.2; D -2.2±2.5, -3.6±3.6, - 4.2±4.2, kg, p=0.59), fat mass (I -1.7±1.0, -2.4±1.5, -3.5±1.5; D -2.8±1.7, -3.4±2.6, - 4.8±3.3, kg, p=0.32), FFM (I -0.3±2.0, -0.1±2.0, -0.0±1.7; D 0.92±1.4, 0.4±1.7, 1.1±1.3, kg, p=0.24), and % body fat (I -1.2±2.1, -1.8±2.1, -2.8±1.9; D -2.6±1.9, -2.8±2.6, - 4.4±3.1 %, p=0.25) changes. No REE differences were seen among groups (I -18±146, - 101±163, -82±126; D -46±137, -17±173, -90±142 kcal/d, p=0.34). No significant nutrient timing x training interactions (mean±SEM) were observed in muscle FSR expressed as percent/day of the alanine pool (I-Pre 13.6±4.3, I-Post 21.1±4.3; D-Pre 15.6±4.0, D-Post 23.8±4.0 %/d, p=0.93). However, FSR was upregulated (p<0.05) in response to a pre-training bout of RE (14.6±2.9 %/d), and trended 54% higher (p=0.075) in response to post-training values (22.5±2.9 %/d). Results indicate that the program was effective in promoting weight and fat loss, while maintaining FFM. Post exercise FSR increased pre-training, and trended higher at 12-wks. However, while some trends were observed warranting additional study, no statistically significant differences were seen between the I and D nutrient timing strategies. | en |
