Effects of chromium and resistive training on muscle strength and body composition

• Published in: Medicine and science in sports and exercise 1996, Vol.28 (1), p.139-144
• Main Authors: HALLMARK, M. A, REYNOLDS, T. H, DESOUZA, C. A, DOTSON, C. O, ANDERSON, R. A, ROGERS, M. A
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Body Composition; Chromium - pharmacology; Double-Blind Method; Drug intoxications. Doping; Humans; Male; Medical sciences; Muscle, Skeletal - drug effects; Pharmacology. Drug treatments; Space life sciences; Weight Lifting - physiology
• ISSN: 0195-9131; 1530-0315
• DOI: 10.1097/00005768-199601000-00025

Sixteen untrained males (23 +/- 4 yr), were studied to determine the effects of chromium (Cr) supplementation (200 micrograms.d-1) and a 12-wk resistive exercise training program on muscle strength, body composition, and Cr excretion. The subjects trained 3 times per week with two sets of 8-10 repetitions at 90% of 1 repetition maximum using Keiser variable resistance machines. Food records were used to estimate Cr intake (approximately 36 micrograms.d-1), energy intake, and the percent kJ from protein. The resistive training program resulted in significant increases in total body muscular strength in both the Cr and placebo groups (24% and 33%; P < 0.05). Body weight, percent body fat, lean body mass, and skinfold thicknesses were unchanged in either group after resistive training. Cr excretion increased in the Cr group after 6 wk of Cr supplementation (0.15 +/- 0.08 vs 1.52 +/- 1.26 micrograms.d-1; P < 0.01) and remained higher at 12 wk of training (2.03 +/- 1.73). These results indicate that Cr supplementation, in conjunction with a progressive, resistive exercise training program, does not promote a significant increase in strength and lean body mass, or a significant decrease in percent body fat. Cr supplementation results in a significant increase in Cr excretion that is not altered by resistive training.