Hunter S. Waldman

Effects of psychological stress during exercise on markers of oxidative stress in young healthy, trained men

PURPOSEnThose engaged in high stress occupations such as firefighters and military personnel are exposed to a variety of psychological and physiological stressors. The combination of mental and physical stress [i.e., dual stress challenges (DSC)] results in significant increases in stress hormones, which causes oxidative stress (OS) and contributes to elevated risk for cardiovascular disease. However, data are needed to determine the impact of DSC on markers of OS in exercise-trained individuals.nnnMETHODnFourteen healthy trained men aged 21-30u202fyrs. participated in a randomized, cross-over design to investigate the impact of DSC on blood markers of OS. The exercise alone condition (EA) consisted of 35u202fmin of cycling at 60% V̇O2 peak. The DSC involved 20u202fmin of mental stress challenges during exercise. Blood was sampled before exercise, as well as immediately, and 30 and 60u202fmin after exercise and analyzed for glutathione (GSH), superoxide dismutase (SOD), hydrogen peroxide (H2O2) and advanced oxidation protein products (AOPP).nnnRESULTnNo significant treatment × time interactions were found. No time effects were noted for SOD, or H2O2; however, AOPP were reduced at 30 (pu202f=u202f.034) and 60u202fmin post exercise (pu202f=u202f.006). GSH was reduced at 30 (pu202f=u202f.009) and 60u202fmin post exercise (pu202f=u202f.031).nnnCONCLUSIONnThese results indicate the OS response from DSC is not greater than that produced from EA in exercise trained men. Future work should investigate the impact of chronic resistance and endurance exercise training on OS resulting from DSC.

A shift toward a high-fat diet in the current metabolic paradigm: A new perspective

OBJECTIVEnInvestigations into the relationship between dietary carbohydrate restriction and health are mixed. Current guidelines for nutrition promote low-fat foods and higher carbohydrate consumption for optimal health and weight loss. However, high-fat, low-carbohydrate diets are revealing both intra- and extracellular adaptations that have been shown to elicit favorable cardiometabolic changes associated with obesity. Moreover, dietary fat is associated with higher satiety levels from the hormones adiponectin, leptin, and cholecystokinin. Additionally, insulin responses from high-glycemic carbohydrates are known to alter these pathways, potentially leading to an increase in energy consumption and a possible mechanism for obesity.nnnCONCLUSIONnThere is convincing evidence of beneficial effects of controlled trials implementing high-fat, low-carbohydrate diets in both sedentary and obese individuals, but longer duration clinical trials are required to confirm this hypothesis.

Impact of occupational footwear during simulated workloads on energy expenditure

Limited research exists on the physiological demands of occupational footwear. Therefore, the purpose of this investigation was to examine the impact of tactical boots (TB) (0.5 kg) and steel-toed work boots (WB) (0.9 kg) on oxygen consumption (V̇O2) and cardiorespiratory responses during simulated walking protocols. Seventeen healthy male (age: 21.9 ± 2.0 years; height: 177.6 ± 4.8 cm; mass: 80.0 ± 9.4 kg) participants completed a total of four 20-min experimental walking trials: (1) WB horizontal protocol, (2) WB graded protocol, (3) TB horizontal protocol, and (4) TB graded protocol, following a randomized repeated measures design. On average, across each protocol, the larger mass of the WB increased absolute V̇O2 by 6.2% and 7.1% for the horizontal and graded protocols, respectively. The WB also caused a significant increase in absolute V̇O2 compared to TB during the horizontal protocol while walking at speeds of 4.0, 5.2, and 6.4 km/h (p < 0.05). No significant differences were observed for heart rate, breathing rate, or ratings of perceived exertion (p > 0.05). The results of this study indicate that wearing occupational footwear with a larger mass can significantly increase energy expenditure compared to footwear of lighter mass. However, energy expenditure increased without changes in physiological measures of energy expenditure. Footwear manufacturers may want to improve footwear design characteristics to maintain required safety guidelines while minimizing footwear mass.

Exogenous ketone salts do not improve cognitive responses after a high-intensity exercise protocol in healthy college-aged males

This study examined the effects of a d-β-hydroxybutyrate (βHB) containing beverage on cognitive and performance measures during a bout of repeated Wingates. Fifteen healthy, college-aged males (mean ± SD; age: 23.1 ± 2.4 years, height: 165.4 ± 2.0 cm, mass: 81.4 ± 9.2 kg) volunteered for the present study. Trial 1 consisted of baseline measures and familiarization for the protocol. During trials 2 and 3, subjects reported to the laboratory, after a 10-h fast, and ingested 11.38 g of βHB or a placebo (PLA) beverage 30 min before exercise. Participants then completed a cognitive challenge (CC), consisting of a 5-min FitLight response task while cycling. At the cessation of the test, participants then completed four 15-s repeated Wingates with 4 min of rest between, followed by another 5-min CC response task. Blood ketones, glucose, and lactate were measured pre-CC and post-Wingates. βHB levels were significantly higher compared with PLA (0.53 vs. 0.21 mmol/L), respectively. A significant order effect was observed across trials 2 and 3 for total FitLight misses and hits, regardless of treatment. Further, there were no significant differences among Wingate power output between treatments, although fatigue index was higher in the βHB group compared with PLA (32.3 vs. 29.4 W/s), respectively. In conclusion, βHB did not improve high-intensity cycling or cognitive performance measures; however, these findings might be partially explained by the absolute dosing protocol used for βHB in the present study as opposed to a relative (g/kg) dosing protocol used in previous research.

Effects of carbohydrate and branched-chain amino acid beverage ingestion during acute upper body resistance exercise on performance and postexercise hormone response

The purpose of this investigation was to examine the individual and combined effects of ingesting carbohydrates (CHO) and branched-chain amino acids (BCAA) during high-volume upper body resistance exercise (RE) on markers of catabolism and performance. Thirteen resistance-trained males completed 4 experimental trials with supplementation, ingesting beverages containing CHO, BCAA, CHO+BCAA, or placebo (PLA) in a randomized, double-blind design. The beverages were ingested in 118-mL servings 6 times during an ∼60-min RE session consisting of bench press, bent-over row, incline press, and close-grip row. Each RE was performed with 5 sets of repetitions at 65% 1-repetition maximum until volitional fatigue. Blood samples were collected at baseline, immediately postexercise, and 60 min postexercise to assess glucose and insulin. Cortisol was assessed immediately and at 60 min postexercise. No significant performance benefits were observed for any RE. CHO+BCAA (152.4 ± 71.4 ng/mL) resulted in the lowest cortisol levels, which was lower than BCAA and PLA (193.7 ± 88.5, 182.8 ± 67.5 ng/mL, p < 0.05), but not different from CHO (165 ± 76.5 ng/mL, p = 0.342). Postexercise insulin concentrations were significantly higher with CHO (4.79 ± 3.4 mU/L) compared with BCAA and PLA (3.7 ± 2.0, 3.5 ± 1.8 mU/L, p < 0.05), but not different from CHO+BCAA (4.3 ± 2.5 mU/L, p = 0.339). There was no treatment effect for glucose, but glucose significantly increased from baseline to immediately postexercise and significantly decreased at 60 min postexercise. Ingesting beverages containing CHO with or without BCAA during upper body resistance exercise may promote a more favorable postexercise less catabolic environment.

Fat grip resistance training improves driving performance in Division I male golfers

Abstract Cummings, PM, Waldman, HS, Krings, BM, Smith, JW, and McAllister, MJ. Effects of fat grip training on muscular strength and driving performance in division I male golfers. J Strength Cond Res 32(1): 205–210, 2018—Fat grip (FG) training is implemented into strength and conditioning programs with the overall goal of increasing grip strength. Previous research assessing the effect of training with increased grip diameters compared with standard Olympic bar diameters has mainly been in acute settings. Therefore, the purpose of this study was to examine to effects FG training compared with normal diameter grip (CON) training during an 8-week periodized resistance training (RT) program in division I male golfers. Subjects (n = 10) were randomly assigned into 2 groups: the FG group (n = 5, scoring average: 75.4 ± 2.0) and CON group (n = 5, scoring average: 75.0 ± 0.5). Both groups participated in 8 weeks of RT (3 d·wk−1). The FG group completed every lift and repetition using FG, compared with the CON training group which used normal diameter bars. Pretraining and posttraining performance variables included swing speed, ball speed, driving distance, driving carry, maximum pull-ups to failure, right and left hand grip strength, and 1 repetition max trap-bar deadlift. The FG group demonstrated significant increases (p ⩽ 0.05) in ball speed, carry, drive distance, and left hand grip strength after 8 weeks of RT. In a population, such as low-handicap division I male golfers, FG training may allow for athletes to increase golf-specific performance after 8 weeks of periodized RT. Strength and conditioning coaches may use FG training over the course of a training program with athletes who require adequate grip strength to further elicit training adaptations.Fat Grip (FG) training is implemented into strength and conditioning programs with the overall goal of increasing grip strength. Previous research assessing the effect of training with increased grip diameters compared to standard Olympic bar diameters has mainly been in acute settings. Therefore, the purpose of this study was to examine to effects FG training compared to normal diameter grip (CON) training during an eight week periodized resistance training (RT) program in Division I male golfers. Subjects (n = 10) were randomly assigned into two groups: the FG group (n = 5, scoring average: 75.4 ± 2.0) and CON group (n = 5, scoring average: 75.0 ± 0.5). Both groups participated in eight weeks of RT (3 days per week). The FG group completed every lift and repetition using FG, compared to the CON training group which used normal diameter bars. Pre- and post-training performance variables included swing speed, ball speed, driving distance, driving carry, maximum pullups to failure, right and left hand grip strength, and one-repetition max trap-bar deadlift. The FG group demonstrated significant increases (p < 0.05) in ball speed, carry, drive distance, and right hand grip strength following eight weeks of RT. In a population, such as low handicap Division I male golfers, FG training may allow for athletes to increase golf specific performance following eight weeks of periodized RT. Strength and conditioning coaches may utilize FG training over the course of a training program with athletes who require adequate grip strength to further elicit training adaptations.