Fourteen trained male anabolic steroid-using bodybuilders (SBBs) (19-41 years) were recruited for the study. Three-day diet records were obtained from SBBs and analyzed. A resting venous blood sample was drawn, and serum/ plasma was subsequently analyzed for various nutritionally related factors. Results showed that mean dietary energy (4,469 ± 1,406 kcal), protein (252 ± 109 g), and vitamin and mineral intakes of SBBs greatly exceeded U.S. Recommended Dietary Allowances. Dietary cholesterol intake was 2.8 times the recommended levels. Mean serum/plasma nutrient concentrations of SBBs were within normal range. However, individual SBBs had a number of serum/ plasma values outside of the normal or recommended range, the most notable of which was hypercalcemia, which was present in 42% of SBBs. Serum/plasma lipids were such as to increase the risk of cardiovascular disease in these subjects.
Robert E. Keith, Michael H. Stone, Ralph E. Carson, Robert G. Lefavi and Steven J. Fleck
Daniel L. Blessing, Robert E. Keith, Henry N. Williford, Marjean E. Blessing and Jeff A. Barksdale
The purpose of this study was to determine the effects of an endurance training program on blood lipids and lipoproteins in adolescents. Fifteen males and 10 females, ages 13 to 18 years, underwent pretest evaluations, including physical measurements, nutritional intake, physical working capacity (PWC), and fasting serum lipid and lipoprotein levels. Physical conditioning consisted of a 16-week progressive endurance training (ET) program 40 min·day1 three times per week. Twenty-five males and females matched for age, sex, and race served as controls. Following the conditioning program, the ET group had a significant increase (p < .05) in PWC and a significant decrease (p < .05) in sum of skinfolds and resting heart rate. A significant decrease (p < .05) was also noted for total cholesterol (TC) and the ratio of TC to high density lipoprotein cholesterol (HDL-C) with a significant increase (p < .05) in HDL-C. No differences were found for the control group. The results suggest that 16 weeks of endurance training favorably improves blood lipid profiles in adolescents.
Keith Brazendale, Michael William Beets, Robert Glenn Weaver, Jennifer Huberty, Aaron E. Beighle and Russell R. Pate
Afterschool programs (ASPs) can provide opportunities for children to accumulate moderate-to-vigorous physical activity (MVPA). The optimal amount of time ASPs should allocate for physical activity (PA) on a daily basis to ensure children achieve policystated PA recommendations remains unknown.
Children (n = 1248, 5 to 12 years) attending 20 ASPs wore accelerometers up to 4 nonconsecutive week days for the duration of the ASPs during spring 2013 (February–April). Daily schedules were obtained from each ASP.
Across 20 ASPs, 3 programs allocated ≤ 30min, 5 approximately 45 min, 4 60 min, 4 75 min, and 4 ≥ 105 min for PA opportunities daily (min·d-1). Children accumulated the highest levels of MVPA in ASPs that allocated ≥ 60 min·d-1 for PA opportunities (24.8–25.1 min·d-1 for boys and 17.1–19.4 min·d-1 for girls) versus ASPs allocating ≤ 45 min·d-1 for PA opportunities (19.7 min·d-1 and 15.6 min·d-1 for boys and girls, respectively). There were no differences in the amount of MVPA accumulated by children among ASPs that allocated 60 min·d-1 (24.8 min·d-1 for boys and 17.1 min·d-1 for girls), 75 min·d-1 (25.1 min·d-1 for boys and 19.4 min·d-1 for girls) or ≥ 105 min·d-1 (23.8 min·d-1 for boys and 17.8 min·d-1 for girls). Across ASPs, 26% of children (31% for boys and 14% for girls) met the recommended 30 minutes of MVPA.
Allocating more than 1 hour of PA opportunities is not associated with an increase in MVPA during ASPs. Allocating 60 min·d-1, in conjunction with enhancing PA opportunities, can potentially serve to maximize children’s accumulation of MVPA during ASPs.
Robert G. Lefavi, Richard A. Anderson, Robert E. Keith, G. Dennis Wilson, James L. McMillan and Michael H. Stone
As the biologically active component of glucose tolerance factor (GTF), the essential trace mineral chromium is now being marketed to athletes. GTF potentiates insulin activity and is responsible for normal insulin function. Thus, insulin's effects on carbohydrate, fat, and protein metabolism are dependent upon the maintenance of adequate chromium stores. Due to excessive chromium loss and marginal chromium intake, athletes may have an increased requirement for chromium. Therefore, in some circumstances the dietary supplementation of a chromium compound may be efficacious. The restoration and maintenance of chromium stores via supplementation would promote optimal insulin efficiency, necessary for high-level athletic performance. However, potential anabolic effects of enhanced insulin function would likely be marginal, and reports of short-term anabolic increases from the supplementation of an organic chromium compound need to be confirmed.
Henry N. Williford, Michele Scharff Olson, Robert E. Keith, Jeffrey M. Barksdale, Daniel L. Blessing, Nai-Zhen Wang and Pete Preston
This investigation evaluated the iron and nutritional status of 12 highly trained aerobic dance instructors who did not take iron supplements (ANS) and 8 who did (AS). A control group (C) consisted of 10 age matched controls. The aerobic instructors had exercised for approximately 3.8 days/wk, 56 min/session for the past 7 yrs. There were no significant differences among groups for energy intake, carbohydrate, protein, fat, nonheme iron, heme iron, or total iron intake (excluding supplemental iron). But both exercise groups had lower ferritin values than the control group. There was also a significant difference in mean cell volume (MCV), with both exercise groups having greater values than the control group. There were no differences among groups for serum iron, total iron binding capacity, transferrin saturation, hematocrit, or hemoglobin. One in three aerobic dance instructors had serum ferritin values below 12 μg · L−1. Results indicate that women exercise leaders have iron profiles that are similar to other groups of female athletes. The increased MCV values suggest runners' macrocytosis or an exercise induced macrocytosis.