Effects of high-intensity resistance training and low-intensity resistance training with vascular restriction on bone...

The aim of this study was to examine and compare the effects of different resistance training protocols on bone marker concentrations in older men. Thirty-seven healthy older male subjects were assigned to one of three groups: high-intensity resistance training (HI-RT, age = 57.5 ± 0.8); low-intensity resistance training with vascular restriction (LI-VRT, age = 59.9 ± 1.0); and control (CON, age = 57.0 ± 1.1). Blood samples were collected before and after 6 weeks of resistance training to measure the changes in bone formation [bone alkaline phosphatase, (Bone ALP)] and resorption (C-terminal cross-linking telopeptide of Type-I collagen, CTX) marker concentrations. A significant main effect for time was detected in Bone ALP to CTX ratio for the exercise groups (p < 0.05). There was a significant group effect for percentage changes in serum Bone ALP (21% for LI-VRT, 23% for HI-RT, and 4.7% for CON) and post hoc analysis identified significant increases in serum Bone ALP concentrations in LI-VRT (p = 0.03) and HI-RT (p = 0.02) when compared with CON. The exercise groups had significantly (p < 0.01) greater strength increases in all upper body and leg exercises compared with CON with no significant differences between the exercise groups except for leg extension strength (HI-RT > LI-VRT, p < 0.05). Serum concentrations of Bone ALP and Bone ALP to CTX ratio improved in both resistance training protocols, suggesting increased bone turnover with a balance favoring bone formation. Therefore, despite using low mechanical load, LI-VRT is a potentially effective training alternative to traditional HI-RT for enhancing bone health in older men.