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  • Author: Robert J. Moffatt x
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Randall L. Wilber and Robert J. Moffatt

Ten trained male runners performed a treadmill exercise test at 80% VO2max under two experimental conditions, carbohydrate (CHO, 7% carbohydrate) and placebo (P), to determine the effect of carbohydrate ingestion on endurance performance (treadmill run time), blood glucose concentration, respiratory exchange ratio (RER), and subjective ratings of perceived exertion (RPE). Treatment order was randomized and counterbalanced and test solutions were administered double-blind. Ingestion took place 5 min preexercise (250 ml) and at 15-min intervals during exercise (125 ml). Performance was enhanced by 29.4% (p ~ 0.05) during CHO (115 ±25 min) compared to P (92 ± 27 min). Blood glucose concentration was significantly greater during CHO (5.6 ± 0.9 mM) relative to P (5.0 ±0.7 mM). There was a significant increase in mean RER following CHO ingestion (.94±.01) compared to P (.90±.01). Average RPE was significantly less during CHO (14.5±2.3) relative to P (15.4±2.4). These data suggest that time to exhaustion of high-intensity treadmill exercise is delayed as a result of carbohydrate ingestion and that this effect is mediated by favorable alterations in blood glucose concentration and substrate utilization.

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Samuel N. Cheuvront, Robert J. Moffatt, Kyle D. Biggerstaff, Shawn Bearden and Paul McDonough

Claims that ENDUROX™ enhances performance by altering metabolic responses to exercise were tested. In a double-blind crossover design, 10 male subjects were randomly assigned to consume 400 mg of placebo or 800 mg ENDUROX™ for 7 days. Cycle ergometry was performed for 30 minutes at 25%, followed by 10 min at 65% of peak oxygen consumption. After a 1-week washout period, subjects performed the identical exercise protocol following 7 days of reciprocal supplemental conditions. Expired gases were collected and analyzed continuously for oxygen consumption, minute ventilation, and respiratory exchange ratio. Heart rate, blood pressure, rating of perceived exertion, blood lactate, and serum glycerol data were also collected at regular intervals. A two-way ANOVA with repeated measures revealed no significant main or interaction effects involving group differences (p > 0.05) between trials for any variable during rest, 25% or 65% (VO2 peak), or recovery. Our findings do not support the ergogenic claims for ENDUROX™.

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Lynn B. Panton, Michael R. Kushnick, J. Derek Kingsley, Robert J. Moffatt, Emily M. Haymes and Tonya Toole

Background:

To evaluate physical activity with pedometers and health markers of chronic disease in obese, lower socioeconomic African American women.

Methods:

Thirty-five women (48 ± 8 y) wore pedometers for 2 weeks. One-way analyses of variances were used to compare age, weight, body mass indices (BMI), and health markers of chronic disease (including blood pressure, cholesterol, triglycerides, glycosylated hemoglobin, fibrinogen, C-reactive protein) between women who were classified by steps per day as sedentary (SED < 5,000; 2,941 ± 1,161 steps/d) or active (ACT ≥ 5,000; 7,181 ± 2,398 steps/d).

Results:

ACT had significantly lower BMI (ACT: 37.2 ± 5.6; SED: 44.4 ± 7.2 kg/m2) and hip circumferences (ACT: 37.2 ± 5.6; SED: 44.4 ± 37.2 cm) and higher total cholesterol (ACT: 230 ± 53; SED: 191 ± 32 mg/dL) than SED. There were no differences in health markers of chronic disease between SED and ACT. Pearson product moment correlations showed significant negative correlations between steps/d and weight (r = –.42), BMI (r = –.46), and hip circumference (r = –.47).

Conclusions:

Increased levels of physical activity were associated with reduced BMI and hip circumferences but were not associated with lower health markers for chronic disease in obese, lower socioeconomic African American women.