Effect of resistance exercise and growth hormone on bone density in older men

OBJECTIVE The purpose of this study was to evaluate whether 16 weeks of heavy resistance exercise training combined with daily growth hormone administration (GH) increases bone mineral density in 64–75-year-old men greater than resistance exercise training without GH supplementation. DESIGN Eighteen healthy, elderly men (67 ± 1 year) followed a 16-week progressive resistance training programme (75–90% maximum strength, 5–10 repetitions/set, 4 sets/day, 4 days/week) after double-blind, random assignment to either a GH (12.5 or 18 μg/kg/day, equivalent to 25 or 36 mU/kg/day, n = 7) or placebo (n = 11) group. MEASUREMENTS Before and at the end of 16 weeks of resistance exercise with or without GH administration, body composition, whole body and regional bone mineral density (BMD) were determined by dual-energy X-ray absorptiometry. Serum osteocalcin and IGF-I were determined by radioimmunoassay before, during and at the end of treatment. RESULTS Increments in fat-free mass and training-specific maximum voluntary muscle strength were similar in both groups after training. Serum insulin-like growth factor-I (IGF-I) and osteocalcin levels were increased (P