درخت حوزه‌های تخصصی

Purpose: Osteoporosis usually starts at a young age and progresses slowly over time. Therefore timely diagnosis of this disease plays an effective role in raising the level of health and public health in the society. The aim of this study was to investigate the relationship between some indicators of osteoporosis and bone mineral density of the pelvis in active elderly men. Methods: This study was semi-experimental. 25 active elderly men with the age range of 60 to 85 years were selected as available and with medical records. Anthropometric characteristics and serum indices of subjects were used as effective indices of osteoporosis. Pearson's correlation coefficient was used to find the relationship between bone mineral density of the pelvis and effector indices, data analysis was done using SPSS version 26 software. Results: The results of this research showed that in the active elderly men, there is a significant relationship between age (P=0.044), body mass index (BMI) (P=0.021), serum calcium (P=0.037) and phosphorus levels (P=0.046) and alkaline phosphatase (P=0.016), with bone mineral density (BMD) of the pelvis. No significant relationship was found between vitamin D with BMD of the pelvis (P=0.055). Conclusion: In general, the results show that there is a significant relationship between bone density and body mass index, calcium and serum alkaline phosphatase indices in active elderly men. Therefore, it is possible to use the serum levels of these indicators in predicting this disease, and exercise may also be one of the influencing factors, so the effect of exercise on other bone density indicators can be investigated.

Background: Force plates are widely used in biomechanics and sports sciences to measure various aspects of human movement. The accuracy and reliability of force plate measurements are critical for valid data interpretation. Aim: The purpose of the study was to evaluate the validity and reliability of the Iranian force plate in the vertical, anterior-posterior, and medial-lateral directions using two manual dynamometers and a load cell. Materials and Methods: In this study, the force plate device utilized had a frequency of 1200 Hz and was manufactured by the Danesh Salar Iranian Company. Additionally, to determine the device's validity, we used Lafayette hand-held dynamometers manufactured in the United States and a load cell by Zemik. Pearson's correlation coefficient was employed to determine the validity of the force plate, while the internal consistency coefficient (ICC) was used to assess the force plate's reliability. Results: The study findings indicated a significant and high level of reliability between the maximum force obtained from the force plate device and manual dynamometer devices and load cell. Additionally, the internal consistency coefficient was found to be excellent (very high) for 20 trials in the three directions of vertical (0.98), anterior-posterior (0.96), and medial-lateral (0.97). Conclusion: The study demonstrated that the Iranian force plate is a reliable device for measuring maximum force in the three directions of vertical, anterior-posterior, and medial-lateral, with very high validity.

Aim and background: The aim of this study was to investigate Kinematics and kinetics Symmetry of Lower Limbs during running at a constant speed. Methods: 28 Elite runner (age: 34.75±6.63years) participated in this study. Running at constant speed was conducted by each subject at 2/5 m.s-1 on treadmill while kinematic and kinetic data were captured at 150 Hz and 300 Hz, respectively. The peak of joint moments and flexion angles in sagittal plane were calculated. The normality and homogeneity of variances assumptions of the dependent variables was tested using Bartlett and Leven’s test. Independent t tests were conducted to examine the symmetry of hip, knee and ankle moments between dominant and non-dominant joints during stance phase of running (p<0.05). Results: results of the present study showed no significant difference exists between dominant and non-dominant lower joints regarding the peak moments of Hip, Knee and ankle in sagittal plane during stance phase (p>0.05) as well as between peak flexion angles during running. Conclusion: Symmetry exists in lower joints sagittal moments and flexion angle during running at the constant speed. According to the results dominant and non- dominant lower joints play propulsive and absorbent roles cooperatively.