Difference in Hamstring-to-Quadriceps Ratio and Dynamic Stability between Limbs in Elderly People

Purpose: previous studies have suggested that thigh muscle imbalance may be a risk factor for knee injury. The Present study aimed to compare Hamstring-to-Quadriceps (H:Q) Ratio and dynamic stability between the two lower limbs of elderly people. Methods: This was a correlational study and by nonprobability sampling 19 healthy community doweling elderly (age=65.93±3.53 yrs.) participated in this study. Dynamic strength and power of knee extensor and flexor muscles and H:Q ratios of each lower limb were measured by isokinetic dynamometer. Dynamic stability was evaluated using the biodex balance system. Paired t test and Wilcoxon test were performed to compare power, strength, H:Q ratio, and balance index of 2 sides. Data analysis were conducted using SPSS software, version 19. Results: Strength and power between two legs was significantly asymmetrical. There was no significant difference in H:Q strength ratios (P=0.057) between the two sides although this ratio was 14.42% greater in weaker leg. Antero-posterior stability index (APSI) was significantly different between two legs (P=0.03), however there is no significant difference in overall stability index (OSI) and medio-lateral stability index (MLSI). Conclusion: The asymmetry between limbs or weakness of the quadriceps and/or hamstring muscle strength and the resultant change in H:Q ratio should be considered in rehabilitation of older adults.