Effects of Running Speed and Duration on a Treadmill on Bone Properties in Ovariectomized Mice / The Japanese Journal of Rehabilitation Medicine

ABSTRACT

Effects of running speed and duration on a treadmill on bone properties were investigated in ovariectomized (OVX) mice. Sixty female ICR mice, twelve-weeks-old, were used in this study. They were divided into six groups of 10 mice each : either the SHAM, OVX, OVX+running groups (AS, AL, BS, BL), randomly. Running groups ran on the treadmill at 8 (A) or 16 (B) m/min, for 25 (S) or 50 (L) min, 5 days/week, for 10 weeks, respectively. After this, both femur and tibia bones were excised from the hind limb, and removed off surrounding tissues. Thereafter, bone mechanical strength (3 point bending test), dry bone weight and also ash content of the bones were determined. Bone mechanical strength and ash content of the femur and tibia in AL, BS, and BL mice were significantly higher than those in OVX mice. Running speed had effects on the bone mechanical strength and ash content of both bones significantly. Group BL showed the maximum values in bone properties among the running groups. This study suggested that a combination of running speed and duration could affect bone properties more significantly than the amount of exercise alone.