Iranian Journal of Orthopedic Surgery

Abstract Introduction& Purpose: Physical activity decreases at the beginning of adolescence, so organized physical activity at school plays an essential role in promoting the health and proper physical development of students. The purpose of this study was to investigate the effect of eight weeks of calisthenics training on core stability, muscle strength, static balance and trunk proprioception of male teenagers. Methods: In this semi-experimental study with a pre-test-post-test design, 40 male high school students aged 15 to 18 in Zavareh city were selected as a sample and randomly divided into two groups: calisthenics training (n=20) and control (n=20). The experimental group received calisthenics training for eight weeks, three times per week, for 60 minutes each session. Before and after the eight-weeks training, static balance, core stability, muscle strength and trunk proprioception were measured using the Stroke balance test, McGill test, chest press, leg press, rowing and error rate of the trunk reconstruction angle at 45° respectively. Results: The results of the independent t- test showed that eight weeks of calisthenics training increased the amount of static balance (p<0.0001), trunk proprioception (p<0.0001), core stability in trunk flexion (p<0.0001), and muscle strength in the rowing and leg press test (p<0.05) significantly.
Conclusion: Overall, the findings from the present study suggest that following an 8-week participation in calisthenics training, trunk proprioception, core stability in flexion, muscle strength and static balance improved in teenagers, therefore, this type of exercises can be used along with other types of exercises or as a suitable alternative in schools.

Abstract Background: Physical activity reduces the risk of bone fractures by decelerating the bone loss and enhancing muscle strength. Such activities promote the bone strength and bone density through bone stimulation. The present study aimed to compare the effect of endurance training with varying intensities on the selected biomechanical properties of femurs in old male Wistar rats.
Methods: 24 male Wistar rats (23 months old) with an average weight of 441.75 grams were randomly divided into 2 experimental and one control grpups: Moderate intensity continuous training (MICT, n = 8), high intensity Interval training (HIIT, n = 8), and control group (CG, n = 8). Moderate and high intensity endurance training sessions were held five days a week with 60-70% and   80-110% of the maximum speed) and high (maximum speed) for eight weeks, respectively. In the MICT and HIET groups, the duration and distance (volume of training) were the same and only the intensity of training differed. Forty-eight hours after the last training session, the rats underwent surgery and their femur removed. Three–point bending flexural test was used to determine the effects of training on modulation, maximum endurance, fracture energy, and femur strength in the rats. The statistical analysis was performed using one-way ANOVA test at P <0.05.
Results: The study results indicated that eight weeks of endurance training with varying intensities had no significant effect on modulation (p < /em>=0.198), bone strength (p < /em>=0.24), fracture energy (p < /em>=0.204), deformation-to-maximum strength (p < /em>=0.89), and femur strength (p < /em>=0.31), and that no significant difference was observed among the three groups.
Conclusion: The biomechanical changes of the bone by such exercises require longer periods of training, which could be examined in future studies.