Comparison of the effect of eight weeks of combined whole body vibration - aerobic training with two different intensities on muscle strength and balance in older men: a randomized clinical trial, a blind

  Aging is a process that occurs over time and leads to negative structural and functional changes in the body, systems, parts and tissues of the body. Whole body vibration (WBV) exercises appear to be an effective alternative to improving physical function in the elderly. The aim of this study was to compare the effect of eight weeks of whole body vibration exercises and rope skipping training with both high and low intensities on muscle strength and balance in elderly men.

 36 elderly men (mean age 65.83 ± 2.16 years; height 169.26 ±2.9 cm; mass 77.04 ± 2.62 kg; body mass index 26.86±0.69 kg.m2) were selected by purposive and available sampling method and matched based on the weight values of the samples and randomly divided into three groups of high intensity (N=12), low intensity (N =12), and control (N =10). Vibration exercises were performed in the high intensity group with a frequency of 40 Hz and in the low intensity group with a frequency of 25 Hz, with a range of 3 mm in both groups. Exposure was intermittent (1 min WBV: 35-40 min rest) for 30 min, three times per week for 8 weeks. In rope training, intensity was applied according to the Borg scale at levels 14 and 13 with 30-35 jumps per minute for both groups. Hand grip strength tests, 30-Second Chair Stand test and Up-and-Go test respectively to evaluate the indicators of muscle strength in the upper and lower limbs and dynamic balance it was performed in the pre-test and at the end of eight weeks. Muscle strength indices in the upper and lower limbs and dynamic balance were assessed at the pre-test and at the end of eight weeks. Statistical analysis of variance with repeated measures was used to analyze the data. Significance level was considered (α=0.05).

 The muscle strength indices in the upper and lower limbs and dynamic balance in the high intensity and low intensity training groups showed a significant improvement compared to the control group (p≤0.05). There was no significant difference between the two training groups in any of the variables (p>0.05).

 It seems that both the intensity of the combined vibration and aerobic program have improved the muscle strength indices in the upper and lower limbs and the dynamic balance of older men. According to the mean and improved (but not significant) indicators of this study in the high intensity group, the choice of high intensity (frequency 40 Hz) will have more beneficial effects than low intensity (frequency 25 Hz).