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  • Author: Stephen F. Crouse x
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John S. Green, Peter W. Grandjean, Shelly Weise, Stephen F. Crouse and J. James Rohack

Although endurance exercise and supplemental estrogen have both been shown to improve serum lipid cardiac risk profiles in postmenopausal women, data regarding a possible synergistic influence are scarce and inconsistent. The purpose of this study was to determine whether such a synergistic influence could be demonstrated. Serum concentrations of total cholesterol (TC), HDL-cholesterol (HDL-C), HDL2-C, HDL3-C, LDL-C, and triglycerides (TG) were obtained from postmenopausal women (N = 45) in each of 4 groups: currently exercising and taking estrogen replacement, exercising and not taking estrogen, sedentary and taking estrogen, and sedentary and not taking estrogen. HDL-C was on average 21% higher (p < .05) and the HDL-C:LDL-C ratio on average 45% higher (p < .05) in the exercise-plus-estrogen group than in any of the other 3 groups. It was concluded that the combination of endurance exercise and estrogen replacement might be associated with better lipid coronary risk profiles in postmenopausal women than either intervention alone.

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Jonathan M. Oliver, Dustin P. Joubert, Steven E. Martin and Stephen F. Crouse

Purpose:

To determine the effects of creatine supplementation on blood lactate during incremental cycling exercise.

Methods:

Thirteen male subjects (M ± SD 23 ± 2 yr, 178.0 ± 8.1 cm, 86.3 ± 16.0 kg, 24% ± 9% body fat) performed a maximal, incremental cycling test to exhaustion before (Pre) and after (Post) 6 d of creatine supplementation (4 doses/d of 5 g creatine + 15 g glucose). Blood lactate was measured at the end of each exercise stage during the protocol, and the lactate threshold was determined as the stage before achieving 4 mmol/L. Lactate concentrations during the incremental test were analyzed using a 2 (condition) × 6 (exercise stage) repeated-measures ANOVA. Differences in power at lactate threshold, power at exhaustion, and total exercise time were determined by paired t tests and are presented as M ± SD.

Results:

Lactate concentrations were reduced during exercise after supplementation, demonstrating a significant condition effect (p = .041). There was a tendency for increased power at the lactate threshold (Pre 128 ± 45 W, Post 143 ± 26 W; p = .11). Total time to fatigue approached significant increases (Pre 22.6 ± 3.2 min, Post 23.3 ± 3.3 min; p = .056), as did maximal power output (Pre 212.5 ± 32.5 W, Post 220 ± 34.6 W; p = .082).

Conclusions:

Our findings demonstrate that creatine supplementation decreases lactate during incremental cycling exercise and tends to raise lactate threshold. Therefore, creatine supplementation could potentially benefit endurance athletes.

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Mandy Clark, Debra B. Reed, Stephen F. Crouse and Robert B. Armstrong

Little published data describe the dietary and physiological profiles of intercollegiate female soccer players; therefore, the purpose of this investigation was to report baseline dietary data, anthropometrics, and performance indices of soccer women during rigorous pre-season training (2 sessions/day) and then during the post-competitive season. Members of a NCAA Division I women’s soccer squad completed 3-day diet records, anthropometrics, and physical tests, including VO2peak. Average body mass was 62 kg with 16% body fat, and no significant pre to post differences were observed. Total energy, carbohydrate (CHO), protein, and fat intakes were significantly greater during the pre-sea-son. Pre-season energy intake met the DRI for females with an “active” lifestyle (37 kcal/kg). While CHO intake failed to meet minimum recommendations to promote glycogen repletion (7–10 g/kg), protein and fat intakes were above minimum recommendations. Pre- and post-season intakes of several micronu-trients were marginal (<75% of the DRI) including vitamin E, folate, copper, and magnesium. VO2peak significantly improved from pre- to post-season (42 and 50 ml/kg/min). In this study female soccer players appeared to meet caloric needs during periods of training but failed to meet minimum CHO and micronu-trient recommendations. Foods higher in protein and fat displaced more CHOrich and nutrient-dense foods within athletes’ energy requirements and satiety limits.

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Roger G. Bounds, Steven E. Martin, Peter W. Grandjean, Barbara C. O’Brien, Cindi Inman and Stephen F. Crouse

To test the effect of diet on the short-term lipid response to exercise, fourteen moderately trained (VO2max: 50.2 ± 6.7 ml/kg/min), healthy men (mean age: 28 ± 4 years) were alternately fed a high fat (60±6.7% fat) and a high carbohydrate (63 ± 3.2% carbohydrate) isoenergetic diet for 2 weeks in a randomized crossover design. During the last 4 days of the treatments, fasting total cholesterol, triglyceride. HDL-cholesterol, and HDL3-cholesterol were measured the day before, and again immediately, 24 hr. and 48 hr after exercise (4190 kJ, 70% VO2max). LDL-cholesterol and HDL2-cholesterol were calculated. Lipid concentrations were adjusted for plasma volume changes after exercise. A 2 (diet) × 4 (time) ANOVA with repeated measures revealed no significant interaction between the diet and exercise treatments. Furthermore, diet alone did not influence lipid concentrations in these trained men. Exercise resulted in an increase in HDL-C (10.7%) and HDL3-C (8.5%) concentrations and a concomitant fall in triglyceride (-25%) and total cholesterol (-3.5%). Thus, we conclude that diet composition does not affect the short-term changes in blood lipids and lipoproteins that accompany a single session of aerobic exercise in moderately trained men.