Background: Despite inadequate empirical validation, sit-to-stand (STS) performance is often used as a proxy measure of lower limb strength among older adults. Furthermore, the relationships between bilateral isokinetic hip, knee, and ankle joint strength and their contributions to STS performances among older adults have not been established. The authors evaluated these relationships on 2 STS tests (5-chair STS test and 30-second chair STS test) in sexagenarian women.
Methods: 47 women (mean age, 64.50 years) performed both STS tests on the same day and bilateral isokinetic (60 degrees/second) hip extensor, hip flexor, knee extensor, knee flexor, ankle plantar flexor, and ankle dorsiflexor strength testing within 7 days after STS testing. Regression analyses were performed using the average weight-adjusted isokinetic hip, knee, and ankle joint strength scores as the independent variables and both STS test scores as the dependent variables.
Results: Regression analyses including all 6 leg strength variables explained 48% (p = .0001) and 35% (p = .007) of the variance in 5-chair STS test scores and 30-second chair STS scores, respectively. Ankle plantar flexor, hip flexor, and knee extensor strength were the strongest predictors for both STS tests.
Conclusions: Although ankle plantar flexor, hip flexor, and knee extensor strength play essential roles in performing the STS movement, most STS variance was unexplained, suggesting that important additional variables are also involved in completing the movement.