Effects of resistance training and chromium picolinate on body composition and skeletal muscle in older men

Abstract

The effects of chromium picolinate (CrPic) supplementation and resistance training (RT) on skeletal muscle size, strength, and power and whole body composition were examined in 18 men (age range 56–69 yr). The men were randomly assigned (double-blind) to groups ( n = 9) that consumed either 17.8 μmol Cr/day (924 μg Cr/day) as CrPic or a low-Cr placebo for 12 wk while participating twice weekly in a high-intensity RT program. CrPic increased urinary Cr excretion ∼50-fold ( P < 0.001). RT-induced increases in muscle strength ( P < 0.001) were not enhanced by CrPic. Arm-pull muscle power increased with RT at 20% ( P = 0.016) but not at 40, 60, or 80% of the one repetition maximum, independent of CrPic. Knee-extension muscle power increased with RT at 20, 40, and 60% ( P < 0.001) but not at 80% of one repetition maximum, and the placebo group gained more muscle power than did the CrPic group (RT by supplemental interaction, P < 0.05). Fat-free mass ( P < 0.001), whole body muscle mass ( P < 0.001), and vastus lateralis type II fiber area ( P < 0.05) increased with RT in these body-weight-stable men, independent of CrPic. In conclusion, high-dose CrPic supplementation did not enhance muscle size, strength, or power development or lean body mass accretion in older men during a RT program, which had significant, independent effects on these measurements.