Early-Morning and Late-Night Maximal Runs: Metabolic and Perceived Exertion Outcomes

People may exercise at the ends of their day to fit activity into their schedule; the purpose of this investigation was to determine if metabolic or perceived exertion outcomes differed between maximal runs early in the morning and late at night. After consuming a standardized, glucose drink, thirteen recreationally active individuals completed an early-morning and a late-night run on the treadmill while researchers measured metabolic (aerobic capacity and substrate usage) and perceived exertion outcomes. Point of application #1: Aerobic capacity (maximal consumption of oxygen) and the usage of fat as a fuel to support energy production during exercise were similar between runs. Point of application #2: Maximal perceived exertion (Borg’s 6-20) was similar during early-morning and late-night runs. Point of application #3: While research indicates that people may prefer activity in the morning or evening, and this might impact metabolic responses to the exercise bout, most of our participants (n=8) identified with no preference for exercising in the early-morning or late-night. Key Words: glucose; CHO shake; VO2max; fat oxidation; effor

Endothelial function and arterial stiffness in young adults with histories of chronic resistance activity

Endothelial dysfunction and arterial stiffness indicate vessel damage and are detectable before overt cardiovascular disease. Chronic cardiorespiratory endurance activity improves arterial endothelial function and stiffness. The influence of chronic resistance activity on these variables is less definitive and thus deserves attention. The primary aim of this investigation was to determine if endothelial dysfunction and arterial stiffness were present in apparently healthy young adults who chronically engage in resistance activity with minimal cardiorespiratory endurance activity. Investigators measured endothelial function as LnRHI and arterial stiffness as AI@75 using the EndoPAT-2000. Investigators measured upper-body muscular strength using a standardized one-repetition maximum (1-RM) bench press. The LnRHI and AI@75 between males and females were compared via an independent-samples t-test and Mann-Whitney U test, respectively. Correlations between 1-RM, bench press to body weight ratio, LnRHI, and AI@75 were evaluated via Pearson’s correlation. Males’ LnRHI was abnormal according to manufacturer standards and lower than females’ (p = .005), but AI@75 was normal and similar for both sexes (p = .22). The 1-RM and bench press to body weight ratio correlated negatively with LnRHI (p = .03 and p = .01, respectively). The bench press to body weight ratio correlated negatively with AI@75 (p = .03), and percentage body fat correlated positively with the AI@75 (p = .003). Young adult males with considerable upper-body muscular strength due to chronic resistance activity, who complete minimal cardiorespiratory endurance activity, appear to have detectable signs of early endothelial dysfunction

Interlimb asymmetry in collegiate American football players: Effects on combine-related performance

The assessment of interlimb asymmetry has been of interest to researchers and practitioners who desire to maximize sport performance. The aim of this study was to explore the relationships between interlimb asymmetry and Combine-related performance testing in collegiate American football players. Twenty-four skill position players (e.g., running backs, defensive backs, and wide receivers) from a Division II university completed all study-related procedures including unilateral countermovement (CMJ) and drop jumps on a force plate, 3-repetition maximum Bulgarian split squats with bar movement tracked by a 3D motion capture system, and their annual spring performance tests (L-drill, pro-agility, 40-yard dash, broad jump, and vertical jump). Using an alpha-level of .05, significant, positive Spearman’s correlations between performance in the L-drill test (Change of Direction test; CoD) and asymmetries in mean peak velocity (rs = .491, p = .015), mean peak power (rs = .467, p = .021), and mean average power (rs = .455, p = .026) were observed. A significant, negative Pearson correlation between unilateral CMJ height asymmetry and vertical jump performance was observed (r = .578, p = .003). Asymmetry in mean peak velocity, mean peak power, and mean average power may negatively influence CoD ability within collegiate American football players