Unlocking mobility: A kinetic perspective on the 30-second chair stand test in older adults

The aging process is accompanied by physiological, biomechanical, and cognitive impairments. In this scenario, functional capacity tests and vertical jumps are used to assess muscle strength and power, which are performed in expensive equipment. Thus, this study analyzed the kinetic behavior of the 30-s chair test, the SJ and CMJ kinetic behavior, and the association between the 30-s with the SJ and CMJ. Twelve older adults (5 females and 7 males) performed the 30-s chair test, the squat jump (SJ), and the countermovement jump (CMJ) on two force platforms. The kinetic behavior of these actions was evaluated. For the 30-s chair test, it was calculated the vertical ground reaction force and linear impulse during the preparatory and lifting phases. The initial vertical forces and the maximal vertical forces, the rate of force development, and the jump height during the SJ and CMJ were calculated. The kinetics of the 30-s chair test is correlated with the kinetics of both SJ and CMJ. The kinetic analysis showed that the ninth repetition of the 30-s test was the cutoff point predictor of the muscle strength and power when compared to the SJ and CMJ tests.