M. Daniel Becque

Effects of oral creatine supplementation on muscular strength and body composition.

PURPOSE The purpose of this investigation was to examine the effects of 6 wk of oral creatine supplementation during a periodized program of arm flexor strength training on arm flexor IRM, upper arm muscle area, and body composition. METHODS Twenty-three male volunteers with at least 1 yr of weight training experience were assigned in a double blind fashion to two groups (Cr, N = 10; Placebo, N = 13) with no significant mean pretest one repetition maximum (IRM) differences in arm flexor strength. Cr ingested 5 g of creatine monohydrate in a flavored, sucrose drink four times per day for 5 d. After 5 d, supplementation was reduced to 2 g x d(-1). Placebo ingested a flavored, sucrose drink. Both drinks were 500 mL and made with 32 g of sucrose. IRM strength of the arm flexors, body composition, and anthropometric upper arm muscle area (UAMA) were measured before and after a 6-wk resistance training program. Subjects trained twice per week with training loads that began at 6RM and progressed to 2RM. RESULTS IRM for Cr increased (P < 0.01) from (mean +/- SD) 42.8 +/- 17.7 kg to 54.7 +/- 14.1 kg, while IRM for Placebo increased (P < 0.01) from 42.5 +/- 15.9 kg to 49.3 +/- 15.7 kg. At post-test IRM was significantly (P < 0.01) greater for Cr than for Placebo. Body mass for Cr increased (P < 0.01) from 86.7 +/- 14.7 kg to 88.7 +/- 13.8 kg. Fat-free mass for Cr increased (P < 0.01) from 71.2 +/- 10.0 kg to 72.8 +/- 10.1 kg. No changes in body mass or fat-free mass were found for Placebo. There were no changes in fat mass and percent body fat for either group. UAMA increased (P < 0.01) 7.9 cm2 for Cr and did not change for Placebo. CONCLUSION Creatine supplementation during arm flexor strength training lead to greater increases in arm flexor muscular strength, upper arm muscle area, and fat-free mass than strength training alone.

Rating Perceived Exertion during Short Duration, Very High Intensity Cycle Exercise

This study compared undifferentiated ratings of perceived exertion (RPE) during short duration, very high intensity cycle exercise using high and low resistance. 30 recreationally trained males (24.2 ± 2.4 yr.) were memory-anchored to the Borg 15-category scale. The high and low resistance exercises were defined by 30-sec. maximum tests assigned in counterbalanced order, with resistances set before testing during an orientation session. High resistance was 10% of body mass. Low resistance resulted in the same total work as the high resistance over the 30-sec. sessions (± 5%) but increased pedal rate. RPE was taken at 8, 13, 18, 23, and 28 sec. during the high and the low resistance exercises. Measurements were compared using a 2-way repeated-measures analysis of variance. RPE was significantly greater (p = .005) for the high than the low resistance exercise at each interval. RPE increased when the subjects were required to pedal against a greater resistance and produce the highest forces. These RPE data are consistent with data from both aerobic cycle and resistance exercise. The data suggest that instantaneous force production, not summed work, is a primary determinant of RPE. All of these observations support Cafarellis theoretical model of effort sense. In conclusion, as an individual generates more force during high resistance exercise than in light resistance exercise, a potential explanation of our results is that the increased motor outflow and corollary sensory signal lead to a greater sense of effort.

Comparison of Memory and Combined Exercise and Memory-Anchoring Procedures on Ratings of Perceived Exertion during Short Duration, Near-Peak-Intensity Cycle Ergometer Exercise

The purpose of this study was to compare ratings of perceived exertion (RPE) following memory-anchoring and two different types of combined exercise and memory-anchoring during short duration, near-peak-intensity cycle exercise. Thirty recreationally trained males volunteered to participate. The M group, n=10, received only verbal instructions prior to the experimental trial. The EM1 group, n = 10, and the EM2 group, n = 10, received the same verbal instructions, but these were administered while participants performed maximal, graded cycle ergometer exercise. The low perceptual anchor was established during light pedaling for both EM1 and EM2. The high perceptual anchor was established during the final stage of the maximal cycle test for EM1 and during a 30-sec. sprint immediately following the final stage of the maximal cycle ergometer testing for EM2. On the experimental trial pedaling at maximal intensity for 30-sec. was against a resistance equal to .10 × body mass (kg) on a cycle ergometer. The Borg 15-category RPE scale was used to record exertional perceptions. RPE was reported at 8, 13, 18, 23, and 28 sec. each trial. Ratings were similar among the three groups. Their linear regression slopes and intercepts were also similar. Memory-anchoring produced similar RPE for two different combined exercise and memory-anchoring procedures. In conclusion, memory-anchoring and combined exercise and memory-anchoring produce similar RPE during high intensity, short duration cycle exercise in young recreationally trained athletes.

Perception of effort during high-intensity exercise at low, moderate and high wet bulb globe temperatures

AbstractThe purpose of this study was to determine the effect of low, moderate and high wet bulb globe temperatures (Twbg) on cardiovascular variables and ratings of perceived exertion (RPE) during moderately prolonged, high-intensity exercise. Six subjects [four men and two women; mean (SD) age, 22.0 (1.2) years; maximum oxygen consumption ({ie519-1}), 51.0 (8.4) ml · kg−1 · min−1] completed 30 min of exercise (80% {ie519-2}) on a cycle ergometer at low [14.7 (2.1)°C], moderate [21.0 (1.5)° C], and high [27.4 (2.3)° C]Twbg. Two additional subjects completed 20 min of exercise in the high temperature condition, but completed 30 min in the moderate and lowTwbg. Heart rate (fc), blood pressure, blood lactate (La), mean skin temperature (

Comparison of Perceived Exertion Ratings during Graded Peak Cycle Exercise between Cigarette Smokers and Nonsmokers

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Effects of High and Low Intensity Weight Training on iEMG and Force 1139

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Letters to the Editor-in-Chief

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