Effects of High-Intensity Interval Training and Moderate-Intensity Continuous Training on Bone Mineral Density in Rat

Moderate intensity continuous training (MICT) has been reported as an effective exercise on bone metabolism. However, very few studies have focused on high-intensity interval training (HIIT). The aim of this study was to investigate and compare the effects of HIIT and MICT training on bone density in middle-aged rats.

30 male Wistar rats (16 weeks old) were randomly divided into three groups: control, MICT and HIIT. Both test groups completed 8 weeks (5 sessions per week) of treadmill training in which the HIIT group performed 10 sessions of running at a speed of 35-47 m/min with a 2-minute active recovery, and the HIIT group ran continuously for 10-45 minutes at a speed of 15-20 meters per minute. The body composition and bone mineral density in the whole body were evaluated through Dual Xray absorptiometry (DXA) at the beginning and after the intervention. The data was analyzed using SPSS software and one-way analysis of variance and Tukey's post hoc tests.

After 8 weeks of intervention, BMD of the whole body and femur increased significantly in both groups (p0≥0.05), although the observed change was greater in the HIIT group (p≥0.05). In addition, in the case of BMD of the lumbar vertebra, no significant difference was observed between all three groups after the intervention (p≤0.05).

These findings show that a period of HIIT and MICT training can improve bone density in middle-aged rats and compared to MICT, HIIT had more benefits on bone density.