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Int J Exerc Sci ; 14(2): 60-75, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34055148


Research suggests that beet juice is beneficial during aerobic exercise. However, the impact of beet juice during primarily anaerobic exercise is equivocal. The purpose of this study was to determine the effects of acute beet juice supplementation on maximal intensity performance during 30-s and 60-s maximal-intensity cycling sprints. Using a double-blind, crossover-study design, 14 anaerobically trained male hockey players completed six Wingate cycling tests: familiarization trials of a 30-s and 60-s Wingate test, followed by 30-s Wingate placebo/beet juice trials, and 60-s Wingate placebo/beet juice trials. Repeated measures ANOVAs were used to compare the change in power between conditions over the duration of each trial. Paired t-tests were run to compare performance between conditions of various work and power variables. One-way ANOVAs were utilized to compare the change between conditions of the 30-s test to the change between conditions of the 60-s test. Beet juice supplementation yielded no statistical differences from placebo in any of the measured variables during the 30-s or 60-s tests (p > 0.05). The percent change for fatigue index was significantly different between the 30-s and 60-s tests (p = 0.032) suggesting less fatigue with beet juice supplementation. Overall, beet juice did not improve maximal intensity performance during 30-s or 60-s cycling sprint tests. Performance during the 60-s bout was not impacted to a greater extent than the 30-s bout after beet juice supplementation. These results suggest that beet juice supplementation does not improve short-duration exercise performance in anaerobically trained athletes.

J Strength Cond Res ; 2020 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-32569125


Beckner, ME, Pihoker, AA, Darnell, ME, Beals, K, Lovalekar, M, Proessl, F, Flanagan, SD, Arciero, PJ, Nindl, BC, and Martin, BJ. Effects of multi-ingredient preworkout supplements on physical performance, cognitive performance, mood state, and hormone concentrations in recreationally active men and women. J Strength Cond Res XX(X): 000-000, 2020-Performance enhancement supplement research has primarily focused on the effectiveness of individual ingredients, rather than the combination. This study investigated the acute effects of 2 multi-ingredient preworkout supplements (MIPS), with beta-alanine and caffeine (BAC) and without (NBAC), compared with placebo (PLA) on anaerobic performance, endurance capacity, mood state, cognitive function, vascular function, and anabolic hormones. Thirty exercise-trained individuals (24.4 ± 4.9 years, 15 men and 15 women) completed a fatiguing exercise protocol on 3 separate occasions, 30 minutes after ingestion of BAC, NBAC, or PLA. Outcomes were analyzed using one-way or two-way repeated-measures analysis of variance, as appropriate (alpha = 0.05). Anaerobic power was greater when supplementing with NBAC (10.7 ± 1.2 W·kg) and BAC (10.8 ± 1.4 W·kg) compared with PLA (10.4 ± 1.2 W·kg) (p = 0.014 and p = 0.022, respectively). BAC improved V[Combining Dot Above]O2peak time to exhaustion (p = 0.006), accompanied by an increase in blood lactate accumulation (p < 0.001), compared with PLA. Both NBAC and BAC demonstrated improved brachial artery diameter after workout (p = 0.041 and p = 0.005, respectively), but PLA did not. L-arginine concentrations increased from baseline to postsupplement consumption of BAC (p = 0.017). Reaction time significantly decreased after exercise for all supplements. There was no effect of supplement on mood states. Exercise-trained individuals looking to achieve modest improvements in power and endurance may benefit from consuming MIPS before exercise.

Int J Sport Nutr Exerc Metab ; 29(3): 315-321, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30160550


Special operation forces participating in mountain warfare/cold weather (MWCW) training have higher energy demands, but adequate fueling is difficult to achieve. The purpose of the study was to determine energy expenditure relative to energy intake and examine fueling patterns during 3 days of MWCW training in Naval Special Warfare Sea, Air, Land (SEAL) Qualification Training (SQT) students. Ten SQT students (age: 23.3 ± 1.8 years, height: 182.3 ± 6.4 cm, and weight: 83.6 ± 4.5 kg) were fitted for heart rate and accelerometer monitors during MWCW training. Total daily energy expenditure was determined using a combination of direct observation and heart rate-VO2 regression. Total daily energy intake was collected using the Automated Self-Administered 24 (ASA24) assessment tool. Total daily energy expenditure for river crossing, alpine skills, and mountain patrol were 3,913 ± 293, 4,207 ± 400, and 5,457 ± 828 kcals, respectively. Reported total daily energy intakes were 2,854 ± 657 (river crossing) and 2,289 ± 680 kcals (mountain patrol), producing 1,044 ± 784 and 3,112 ± 1,420 kcal deficits, respectively. SQT students consumed 258 ± 95 g (3.1 ± 1.3 g·kg-1·day-1) of carbohydrates, 130 ± 55 g (1.6 ± 0.7 g·kg-1·day-1) of protein, and 113 ± 39 g (1.4 ± 0.5 g·kg-1·day-1) of fat. MWCW training evolutions elicited high total daily energy expenditure and inadequate energy intake, especially before and during active training sessions, which may lead to decreased work output, early onset fatigue, and increased risk of injury. Increasing total daily energy intake by providing fuel/fluids, primarily carbohydrates, during the planned breaks and "downtime" of each training evolution and focusing on provision of the balance of calories/macronutrients needed for a more complete and expedited recovery over dinner and evening snacks will help bridge the energy gap.

Temperatura Baixa , Ingestão de Energia , Metabolismo Energético , Condicionamento Físico Humano , Adulto , Carboidratos da Dieta/administração & dosagem , Frequência Cardíaca , Humanos , Masculino , Militares , Necessidades Nutricionais , Estudantes , Adulto Jovem
Appl Physiol Nutr Metab ; 43(4): 381-386, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29144888


The purpose of this study was to identify and compare energy requirements specific to Special Operations Forces in field training, in both cool and hot environments. Three separate training sessions were evaluated, 2 in a hot environment (n = 21) and 1 in a cool environment (n = 8). Total energy expenditure was calculated using doubly labeled water. Dietary intake was assessed via self-report at the end of each training mission day, and macronutrient intakes were calculated. Across the 3 missions, mean energy expenditure (4618 ± 1350 kcal/day) exceeded mean energy intake (2429 ± 838 kcal/day) by an average of 2200 kcal/day. Macronutrient intakes (carbohydrates (g/(kg·day body weight (bw))-1) = 3.2 ± 1.2; protein (g/(kg·day bw)-1) = 1.3 ± 0.7; fat (g/(kg·day bw)-1) = 1.2 ± 0.7) showed inadequate carbohydrate and possibly protein intake across the study period, compared with common recommendations. Total energy expenditures were found to be similar between hot (4664 ± 1399 kcal/day) and cool (4549 ± 1221 kcal/day) environments. However, energy intake was found to be higher in the cool (3001 ± 900 kcal/day) compared with hot (2200 ± 711 kcal/day) environments. Based on the identified energy deficit, high variation in energy expenditures, and poor macronutrient intake, a greater attention to feeding practices during similar training scenarios for Special Operations Forces is needed to help maintain performance and health. The differences in environmental heat stress between the 2 climates/environments had no observed effect on energy expenditures, but may have influenced intakes.

Temperatura Baixa , Ingestão de Alimentos , Metabolismo Energético , Meio Ambiente , Temperatura Alta , Camada de Gelo , Militares , Condicionamento Físico Humano/métodos , Adulto , Composição Corporal , Nível de Saúde , Transtornos de Estresse por Calor/metabolismo , Transtornos de Estresse por Calor/fisiopatologia , Humanos , Necessidades Nutricionais , Estado Nutricional , Valor Nutritivo , Aptidão Física , Adulto Jovem
Mil Med ; 180(12): 1239-46, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26633668


The purpose of this study was to evaluate the nutrient intake of male and female Soldiers in the 101 st Airborne Division (Air Assault) compared to sports nutrition standards for athletes, and to identify suboptimal eating characteristics that may impair physical performance and jeopardize military readiness. Male and female Soldiers from the 101 st Airborne Division (Air Assault) completed a 24-hour dietary recall and nutrition history questionnaire before anthropometric and body composition measurements were taken. Compared to sports nutrition guidelines, Soldiers of the 101 st under consume carbohydrates (males: 3.9 ± 2.0 vs. 5.0 g/kg, p < 0.001; females: 4.0 ± 2.1 vs. 5.0 g/kg, p = 0.001), male Soldiers eat too much fat (32.4% of kcal vs. <30% of kcal, p = 0.000) and saturated fat (males: 10.5 ± 3.9% of kcal vs. 10.0% of kcal, p = 0.044), and both males and females follow a meal pattern that may not optimize energy availability throughout the day. Eating too much fat and under fueling carbohydrate may negatively impact the adaptations to physical training and compromise overall health. Although Soldiers continue to participate in arduous training programs, future research should be aimed at determining the energy and macronutrient needs to fuel and recover from specific types of military training.

Dieta/normas , Ingestão de Energia/fisiologia , Metabolismo Energético/fisiologia , Militares , Avaliação Nutricional , Ciências da Nutrição e do Esporte/normas , Adulto , Registros de Dieta , Feminino , Humanos , Masculino , Política Nutricional , Necessidades Nutricionais , Inquéritos e Questionários , Estados Unidos , Adulto Jovem