Masters Thesis

Effects of creatine supplementation and resistance training on bone turnover markers in older men: a pilot study

PURPOSE: The primary purpose of this pilot study was to determine the effect of creatine supplementation, both with and without resistance training, on human bone. Serum bone turnover markers (BTMs) for bone formation and resorption were used as outcome measures. A secondary purpose was to investigate changes in body composition and strength resulting from the supplement and resistance training regimens. METHODS: Eight healthy older men aged 66-79 years old (71.8 ± 4.1 yr; 91.4 ± 19.3 kg; 177.9 ± 6.3 cm) were randomized into three groups: creatine only (Cr, n = 3), creatine and resistance training (Cr+RT, n = 3) and placebo (PLA, n = 2). The men underwent 12 weeks of treatment which included supplementation with creatine (0.3 g/kg for 5 days and 0.07 g/kg thereafter) or placebo. Subjects were measured pre and posttest using four serum BTMs: osteocalcin (OC), procollagen I intact n-terminal propeptide (PINP), and N and C-Telopeptide (NTx, CTx). Those in the Cr+RT group performed 12 exercises, 10 repetitions, and 3 sets session-1 for 12 weeks. All subjects underwent dual x-ray absorptiometry (DXA), and one-repetition maximum strength testing. RESULTS: Study participants in the Cr and Cr+RT groups experienced increases in osteocalcin (Cr 2.8%, Cr+RT 13.1%) as did those in PLA group (12.0%). PINP also increased in those groups receiving creatine (Cr 2.2%, Cr+RT 3.6%), yet it decreased in the PLA group (-15.6%). Bone resorption markers (NTx and CTx) decreased in the Cr-alone group (-11.9% and -23.1%, respectively), increased somewhat in the Cr+RT group (0.8% and 10.4%, respectively), and increased by a greater amount for those in the PLA group (22.5% and 38.9%, respectively). Small changes in lean mass (Cr 1.8%, Cr+RT 3.7%, PLA -2.9%) and fat % (Cr 0.3%, Cr+RT -0.2%, PLA 2.5%) were observed. Changes in strength were greatest in the Cr+RT group, but notable increases were also seen in the Cr-alone group (leg press: Cr 20%, Cr+RT 55%, PLA 5%; knee extension: Cr 10%, Cr+RT 43%, PLA 6%; and bench press: Cr 9%, Cr+RT 27%, PLA 0%). CONCLUSION: Observable patterns in change in serum BTMs indicate that creatine alone, and with resistance training, may have a positive effect on bone metabolism. Body composition and strength changes in creatine-supplemented groups were consistent with prior studies using a similar cohort and methodology.

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