Equal BMD after daily or triweekly exercise in growing rats.

Area of Science:

• Exercise Physiology
• Bone Biology
• Animal Models

Background:

• Resistance training is crucial for bone health.
• Understanding optimal training frequency for bone mineral density (BMD) enhancement is important.
• Previous research has not directly compared continuous versus interrupted resistance training schedules in growing animals.

Purpose of the Study:

• To compare the efficacy of continuous (3 days/wk) versus interrupted (6 days/wk) resistance training on bone mineral density (BMD) in growing male rats.
• To assess the impact of different resistance training frequencies on serum osteocalcin levels.
• To determine if training volume equivalence influences the effectiveness of resistance training protocols.

Main Methods:

• Young male rats were divided into three groups: Control, 3 days/wk resistance trained (RT3), and 6 days/wk resistance trained (RT6).
• Training involved climbing a vertical ladder with appended weights for 6 weeks.
• Bone mineral density (BMD) was assessed using dual-energy X-ray absorptiometry (DXA), and serum osteocalcin (OC) was measured.

Main Results:

• Both RT3 and RT6 groups showed significantly greater tibial BMD compared to the Control group.
• Serum osteocalcin levels were significantly elevated in both RT3 and RT6 groups relative to the Control group.
• No significant differences in BMD or serum osteocalcin were observed between the RT3 and RT6 groups.

Conclusions:

• Both continuous and interrupted resistance training programs are equally effective in enhancing bone mineral density (BMD) in young, growing rats.
• Training frequency does not appear to be a critical factor when total weekly training volume is matched.
• These findings suggest that adherence to either training schedule can yield similar benefits for bone health in this model.