Strength and torque consistency of the hip and knee flexors and extensors: A comparative study of elderly and young individuals

Objectives: To assess the strength of the flexors and extensors of the knee and hip joints in elderly and in young individuals. Methods: A group of elderly women (N = 47) and men (N = 44) aged 65 and older and a group of young women (N = 15) and men (N = 15) aged between 20 and 30 years were tested for the isokinetic strength of the hip and knee flexors and extensors. Results: A typical age-related decrease in the strength of all tested muscles was observed but the decline in hip muscles strength, compared to those of the knee, was significantly lower, by about 10%. Moreover, women presented a significantly better strength preservation than men. The consistency of performing the repeated isokinetic efforts was higher, in some instances significantly so, in the older (range: 4.4-11%) than in the younger (3.5-6.3%) individuals but the differences do not seem to convey any clinical significance. CONCLUSION: These findings enable clinicians to set valid rehabilitation goals, particularly with respect to hip dysfunction in the elderly. Furthermore, healthy elderly individuals perform maximal isokinetic tests with substantially similar degree of gross motor control compared to that of young individuals.