Determining a Resting Metabolic Rate Prediction Equation for Collegiate Female Athletes.

Watson, AD, Zabriskie, HA, Witherbee, KE, Sulavik, A, Gieske, BT, and Kerksick, CM. Determining a resting metabolic rate prediction equation for collegiate female athletes. J Strength Cond Res 33(9): 2426-2432, 2019-A lack of evidence exists regarding the accuracy of common resting metabolic rate (RMR) prediction equations in athletic female populations. The purpose of this research was to measure RMR in a large cohort of NCAA Division II female athletes and use regression techniques to develop new prediction equations. Sixty-six female athletes from 11 different sports completed this protocol, which included skinfold measurements followed by an RMR assessment using indirect calorimetry. The average RMR was 1,466 ± 150 kcal·d. Many between-sport differences in body composition were identified, with gymnastics athletes having the lowest body fat percentage (p < 0.05) and basketball athletes having the greatest absolute fat-free mass (p < 0.05). Resting metabolic rate was moderately correlated (p < 0.05) with height (r = 0.52), total mass (r = 0.59), and fat-free mass (r = 0.54). Two equations were developed, both of which were more accurate for this population than other RMR prediction equations. One of the new equations, which used height and body mass as covariates (equation 1), was slightly more accurate than the equation using body composition parameters (equation 2). The new equations were cross-validated using a randomly selected subset (n = 22) of the original sample. The subset did not show statistically different results from the remainder of the sample (n = 44) between equation 1 (p = 0.083) and equation 2 (p = 0.22). Equation 1, which had more easily measurable parameters, exhibited heightened accuracy, which has important implications for implementation among athletes, coaches, and athletic support staff.

Physiologic, Metabolic, and Nutritional Attributes of Collegiate Synchronized Swimmers.

Synchronized swimming is a sport that requires high levels of strength, power, and endurance, as well as artistic skill to perform in an aquatic environment. Purpose: The purpose of this study was to identify physiological characteristics and dietary habits of collegiate synchronized swimmers. Methods: A total of 21 female participants (mean [SD] age = 20.4 [1.6] y, height = 168.0 [4.9] cm, and weight = 64.4 [8.7] kg) performed resting metabolic rate test. Body composition was determined using skinfolds (4-site and 7-site) and dual-energy X-ray absorptiometry (DEXA). Dietary intake was assessed using 4-d dietary records. Results: Resting metabolic rate was 110.9 (10.5) kJ/kg normalized to body weight and calculated relative daily caloric intake was 121.4 (42.3) kJ/kg. Estimated energy availability ranged from 109.1 (52.1) to 126.7 (52.6) kJ/kg fat-free mass per day and was correlated (P = .045) to resting metabolic rate. Percentage body fat measured using DEXA (28.7% [4.8%] fat) was higher than both 4-site (25.7% [4.8%] fat, P = .001) and 7-site (25.3% [4.7%] fat, P = .001) skinfold values. No significant correlations were reported between bone mineral density, body composition, and dietary intake data. Conclusions: Synchronized swimmers have similar body composition and training habits as other competitive aquatic athletes. Dietary intake data revealed low energy availability and lower than recommended macronutrient levels.

Metabolic impact of protein feeding prior to moderate-intensity treadmill exercise in a fasted state: a pilot study.

BACKGROUND: Augmenting fat oxidation is a primary goal of fitness enthusiasts and individuals desiring to improve their body composition. Performing aerobic exercise while fasted continues to be a popular strategy to achieve this outcome, yet little research has examined how nutritional manipulations influence energy expenditure and/or fat oxidation during and after exercise. Initial research has indicated that pre-exercise protein feeding may facilitate fat oxidation while minimizing protein degradation during exercise, but more research is needed to determine if the source of protein further influences such outcomes. METHODS: Eleven healthy, college-aged males (23.5 ± 2.1 years, 86.0 ± 15.6 kg, 184 ± 10.3 cm, 19.7 ± 4.4%fat) completed four testing sessions in a randomized, counter-balanced, crossover fashion after observing an 8-10 h fast. During each visit, baseline substrate oxidation and resting energy expenditure (REE) were assessed via indirect calorimetry. Participants ingested isovolumetric, solutions containing 25 g of whey protein isolate (WPI), 25 g of casein protein (CAS), 25 g of maltodextrin (MAL), or non-caloric control (CON). After 30 min, participants performed 30 min of treadmill exercise at 55-60% heart rate reserve. Substrate oxidation and energy expenditure were re-assessed during exercise and 15 min after exercise. RESULTS: Delta scores comparing the change in REE were normalized to body mass and a significant group x time interaction (p = 0.002) was found. Post-hoc comparisons indicated the within-group changes in REE following consumption of WPI (3.41 ± 1.63 kcal/kg) and CAS (3.39 ± 0.82 kcal/kg) were significantly greater (p < 0.05) than following consumption of MAL (1.57 ± 0.99 kcal/kg) and tended to be greater than the non-caloric control group (2.00 ± 1.91 kcal/kg, p = 0.055 vs. WPI and p = 0.061 vs. CAS). Respiratory exchange ratio following consumption of WPI and CAS significantly decreased during the post exercise period while no change was observed for the other groups. Fat oxidation during exercise was calculated and increased in all groups throughout exercise. CAS was found to oxidize significantly more fat (p < 0.05) than WPI during minutes 10-15 (CAS: 2.28 ± 0.38 g; WPI: 1.7 ± 0.60 g) and 25-30 (CAS: 3.03 ± 0.55 g; WPI: 2.24 ± 0.50 g) of the exercise bout. CONCLUSIONS: Protein consumption before fasted moderate-intensity treadmill exercise significantly increased post-exercise energy expenditure compared to maltodextrin ingestion and tended to be greater than control. Post-exercise fat oxidation was improved following protein ingestion. Throughout exercise, fasting (control) did not yield more fat oxidation versus carbohydrate or protein, while casein protein allowed for more fat oxidation than whey. These results indicate rates of energy expenditure and fat oxidation can be modulated after CAS protein consumption prior to moderate-intensity cardiovascular exercise and that fasting did not lead to more fat oxidation during or after exercise.

Effect of Carbohydrate, Caffeine, and Carbohydrate + Caffeine Mouth Rinsing on Intermittent Running Performance in Collegiate Male Lacrosse Athletes.

Dolan, P, Witherbee, KE, Peterson, KM, and Kerksick, CM. Effect of carbohydrate, caffeine, and carbohydrate + caffeine mouth rinsing on intermittent running performance in collegiate male lacrosse athletes. J Strength Cond Res 31(9): 2473-2479, 2017-Recently, an interest has developed in the potential to rinse the oral cavity with key nutrients to impact various types of exercise and presumably sporting performance. Although multiple studies examining carbohydrate mouth rinsing have been completed, conflicting evidence surrounding caffeine mouth rinsing persists, and no research has explored its ability to impact high-intensity, intermittent running performance. This study investigated the independent and synergistic ability of carbohydrate and caffeine mouth rinsing to improve intermittent running performance. The Yo-Yo Intermittent Recovery Test-Level 1 (Yo-Yo Level 1) was completed in 10 collegiate (National Collegiate Athletic Association [NCAA] Division II) male lacrosse players after a 10-second mouth rinse with a solution of either carbohydrate (CHO), caffeine (CAF), carbohydrate + caffeine (CHO + CAF), placebo (H2O), or a no rinse control (CON). No significant improvements in Yo-Yo IRT-1 performance were found (p > 0.05). Perceptual indications of effort (i.e., rating of their perceived exertion [RPE]) were significantly lower (p ≤ 0.05) in CHO and CHO + CAF when compared with CON after speed level 11. Interestingly, RPE levels were nonsignificantly lower in all but one level of the Yo-Yo Level 1 for CHO in comparison with other groups. Carbohydrate and caffeine mouth rinsing seems to exert no impact on running performance before maximal intermittent running in a group of male collegiate lacrosse players.