Background and purpose: Previous research has shown that improving lower extremity muscle strength plays an important role in prevention of falls in older people. The aim of this study was to investigate the relationship between the changes of lower extremity muscle strength and postural control ability in elderly after a hydrotherapy program.
Materials and methods: In a clinical trial, 30 elderly male were randomly selected and classified into intervention (mean age 65.4 years, mean height 169.3 cm, and mean weight 70.8 kg) and control groups (mean age 63.6 years, mean height 1688 cm, and mean weight 70.9 kg). The intervention group participated in an aquatic exercise program for 8 weeks while the control group had no intervention. Postural sway parameters and muscle strength were evaluated before and after the program using the Biodex balance system and hand held dynamometer (HHD) respectively. Pearson correlation test was used for data analysis (P≤0.05).
Results: The results showed a significant relationship between the changes of plantar flexors muscle strength and postural control ability after the intervention (P<0.05), but this relationship was not significant in the case of other muscles (P>0.05).
Conclusion: Compared with other lower extremity muscles, increase in plantar flexors muscle strength seems to have a major role in improving the postural control ability in elderly people. So, posterior muscles of the leg should be considered in planning exercises that aim at improving balance in older people.
 
(Clinical Trials Registry Number: IRCT2016031227022N1)