THE EFFECTS OF SHORT-TERM NON-AXIAL LOADING RESISTANCE TRAINING ON CALCIUM REGULATING HORMONES

Abstract

A 12-week study was undertaken to determine the effects of non-axial loading resistance training (RT) on serum parathyroid hormone (PTH), calcitonin (CAL), bone mineral content (BMC) and bone mineral density (BMD). Eleven untrained pre-menopausal women were divided into either a RT (n = 6; mean ± SE; age = 29.4 ± 3.2) or control (CON; n = 5; mean ± SE; age = 39.4 ± 4.1) group. The RT group performed single-joint machine resistance exercise three days a week while CON performed no training. Data were analyzed using a 2 ± 2 repeated measures ANOVA. Post-testing showed significant (p < 0.05) increases in maximal strength in the RT group only. Increases in IRM chest press (44%), shoulder press (31%), lat pulldown (31%), leg curl (35%) and knee extension (32%) were observed. Due to the interactive nature of PTH and CAL in calcium resorption and deposition, a CAL to PTH ratio is proposed to quantify the state of bone turnover. No differences were seen (p > 0.05) between and within groups pre- and post-testing for calcium regulating hormones. Whole body BMC (g; RT; pre = 2058.7 ± 163.7, post = 2073.7 ± 165.9; CON: pre = 2170.9 ± 111.3, post = 2205.7 ± 92.3) and BMD (g/cm2; RT; pre = 1.014 ± 0.050, post = 1.020 ± 0.052; CON: pre = 0.061 ± 0.032, post = 1.064 ± 0.031) did not change in either group from pre- to post-test. The results of this study suggest that RT of this type produces changes in muscular strength without affecting calcium regulating hormones, BMC, or BMD.Table