title: 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 micromol Cr/day (924 microg 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 approximately 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.
authors.affiliation: Donald W. Reynolds Department of Geriatrics, University of Arkansas for Medical Sciences, and Veterans Affairs Geriatric Research, Education, and Clinical Center, Little Rock, Arkansas 72205, USA. campbellwaynew@exchange.uams.edu
authors.forename: W W
authors.initials: WW
authors.lastname: Campbell
authors.forename: L J
authors.initials: LJ
authors.lastname: Joseph
authors.forename: S L
authors.initials: SL
authors.lastname: Davey
authors.forename: D
authors.initials: D
authors.lastname: Cyr-Campbell
authors.forename: R A
authors.initials: RA
authors.lastname: Anderson
authors.forename: W J
authors.initials: WJ
authors.lastname: Evans
mesh_terms: D000368:Aged; D001823:Body Composition / Q000187:drug effects / Q000502:physiology*; D003401:Creatine / Q000652:urine; D004032:Diet; D004734:Energy Metabolism / Q000502:physiology; D006801:Humans; D007502:Iron Chelating Agents / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D010848:Picolinic Acids / Q000494:pharmacology*; D012885:Skinfold Thickness; D014891:Weight Lifting / Q000502:physiology*
chemical_list: D007502:Iron Chelating Agents; D010848:Picolinic Acids; D003401:Creatine; C030614:picolinic acid