Effects of Resistive Training and Chromium Picolinate on Body Composition and Skeletal Muscle Size in Older Women
in International Journal of Sport Nutrition and Exercise MetabolismClick name to view affiliation
This study assessed the effect of resistive training (RT), with or without high-dose chromium picolinate (Cr-pic) supplementation, on body composition and skeletal muscle size of older women. Seventeen sedentary women, age range 54-71 years. BMI 28.8±2.4 kg/m2. were randomly assigned (double-blind) to groups (Cr-pic. n = 9; Placebo, n = 8) that consumed either 924 μg Cr/d as Cr-pic or a low-Cr placebo (<0.2 μg Cr/d) during a 12-week RT program (2 day/ week, 3 sets · exercise−1 · d1,80% of 1 repetition maximum). Urinary chromium excretion was 60-fold higher in the Cr-pic group, compared to the Placebo group (p < .001), during the intervention. Resistive training increased maximal strength of the muscle groups trained by 8 to 34% (p < .001), and these responses were not influenced by Cr-pic supplementation. Percent body fat and fat-free mass were unchanged with RT in these weight-stable women, independent of Cr-pic supplementation. Type I and type II muscle fiber areas of the m. vastus lateralis were not changed over time and were not influenced by Cr-pic supplementation. These data demonstrate that high-dose Cr-pic supplementation did not increase maximal strength above that of resistive training alone in older women. Further, these data show that, under these experimental conditions, whole body composition and skeletal muscle size were not significantly changed due to resistive training and were not influenced by supplemental chromium picolinate.
W.W. Campbell is with the Department of Foods and Nutrition at Purdue University, West Lafayette, IN 47907. R.A. Anderson is with the USDA Beltsville Human Nutrition Research Center, Beltsville. MD 20705. L.J.O. Joseph, S.L. Davey. J. Hinton, and W.J. Evans are with the Nutrition, Metabolism and Exercise Program in the Reynolds Department of Geriatrics and GRECC at the University of Arkansas for Medical Sciences, Little Rock, AR 72205.
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