The effect of exercise intervention on isokinetics and gait parameters The strength of the flexor and extensor muscles of lower extremities is highly correlated with the capacity to execute mobility tasks." Previous studies have shown that stronger knee extensor and flexor strength were associated with better balance and older people with a history of falling exhibited less plantar flexion during the push-off phase of the gait cycle. Weak ankle plantar flexors can cause a longer double support phase during walking, and a reduced double support phase was reported as a strong indication of improve ment in movement stability. Thus, our results indicate that increasing muscle strength in lower limbs can improve older individuals' ability to successfully perform daily tasks In addition, the combined intervention integrated classical training movements with Tai Chi. This was expected to have more significant impacts on multi-joint muscle strength than the interventions using Tai Chi exercise only. 17 However, a direct comparison between the combined intervention and Tai Chi exercise is ideally needed to make his conclusion.