No abstract

The purpose of this study was to examine the effect of a 6-wk deep water running program on the maintenance of cardiorespiratory performance (VO2max, ventilatory threshold, running economy); metabolic measurements of blood glucose, blood lactate, and plasma norepinephrine; and body composition. Sixteen trained male runners (VO2max = 58.6 +/- 3.6 ml.kg-1.min-1) were assigned to one of two groups matched by VO2max, treadmill run (R) or water run (WR). Subjects participated in their respective training programs, which consisted of workouts of a) 30 min at 90-100% VO2max and b) 60 min at 70-75% VO2max alternated daily for 5 d.wk-1. Following 6 wk of workouts, no significant intra- or intergroup differences were observed for treadmill VO2max for R (pre = 58.4 +/- 2.3, post = 60.1 +/- 3.6 ml.kg-1.min) and WR (pre = 58.7 +/- 4.7, post = 59.6 +/- 5.4 ml.kg-1.min-1). Similarly, ventilatory threshold was unaltered in R (pre = 47.5 +/- 1.8, post = 48.2 +/- 3.3 ml.kg-1.min-1) and WR (pre = 46.5 +/- 6.4, post = 47.4 +/- 6.7 ml.kg-1.min-1), nor were there any changes in running economy in R (pre = 48.4 +/- 2.3, post = 48.9 +/- 2.0 ml.kg-1.min-1 at 255 m.min-1) and WR (pre = 51.8 +/- 2.0, post = 48.9 +/- 2.2 ml.kg-1.min-1 at 255 m.min-1). No significant differences were observed within or between groups for maximal blood glucose, blood lactate, and plasma norepinephrine concentration as well as for body composition indices. It was concluded that deep water running may serve as an effective training alternative to landbased running for the maintenance of aerobic performance for up to 6 wk in trained endurance athletes.

We determined the effect of supervised physical training, without dietary intervention, on body composition of obese girls. The subjects were 25 obese 7-to 11-year-old black girls, divided into physical training and lifestyle education groups which were comparable on baseline body composition; 22 girls finished all aspects of the study. Twelve girls engaged in aerobic training (10 weeks, 5 daydweek) while 10 engaged in weekly lifestyle discussions without formal physical training. Total body and regional body composition were measured with dual energy x-ray absorptiometry, skinfolds and circumferences. Aerobic fitness was measured by heart rate response to submaximal treadmill exercise. The physical training group attended 94% of scheduled sessions and kept their heart rates at an average of 163 bpm for 28 minutedsession. The lifestyle group attended 95% of their sessions; they remained stable in aerobic fitness and most body composition measurements. The physical training group showed a significant improvement in aerobic fitness and a significant decline of 1.4% body fat. Skinfold and circumference indices of fatness also declined significantly in the training group. We conclude that controlled Submitted for publication November 1.1994. Accepted for publication in final form January 9,1995.

The effects of supervised physical training (PT) and lifestyle education (LSE) on risk factors for coronary artery disease and non-insulin-dependent diabetes mellitus were compared in obese 7- to 11-yr-old black girls. The subjects were divided into two groups. The PT group (N = 12) completed a 5-d.wk-1, 10-wk, aerobic training program; and the LSE group participated in weekly lifestyle discussions to improve exercise and eating habits. The PT group showed a significant increase in aerobic fitness (P < 0.05) and decrease in percent body fat (P < 0.05), while the LSE group declined significantly more in dietary energy and percent of energy from fat (P < 0.05). Fasting insulin did not change significantly. The LSE group declined significantly more than the PT group in glucose (P < 0.05), and glycohemoglobin declined from baseline in both groups (P < 0.05). Lipid changes were similar in the two groups: total cholesterol/high density lipoprotein cholesterol (P < 0.01) and triglycerides (P < 0.05) declined, the low density lipoprotein (LDL)/apoproteinB ratio increased (which indicates a decrease in small dense LDL) (P < 0.05) and lipoprotein(a) increased (P < 0.05). Thus, the interventions were similarly effective in improving some diabetogenic and atherogenic factors, perhaps through different pathways; i.e., the PT improved fitness and fatness, while the LSE improved diet. Exercise and diet-induced changes in lipoprotein(a) require further investigation.