Effects of Dual Task and Repetition on Five-Times Sit-To-Stand Task in Healthy Young Adults

Clinically, the five-times STS task (FTSTS) is used to assess balance and muscle efficiency in the lower extremities of various populations. However, the changes that occur in body mechanics with greater repetitions and the effects of dual tasking while performing FTSTS are currently unknown. PURPOSE: To determine the effects of dual tasking and multiple repetitions on the FTSTS task in healthy, young adults. METHODS:10 healthy adults (age 24 (4.1) years) stood up and sat down five times fast without (SingleTask) and with a concurrent cognitive task of counting backwards by 3 (DualTask). Time to complete FTSTS was measured. Impulse (Ns/BW), peak force (N/BW), and power (Nm/BW.s) were calculated using ground reaction forces. A 2-way ANOVA and paired samples t-test were conducted. RESULTS: Participants took significantly longer to complete FTSTS during DualTask (8.16[1.77]s) vs. SingleTask (7.38[1.08]; p=.05). Concentric impulse significantly increased from 0.55 (0.02) during SingleTask to 0.59 (0.03) during DualTask (p=.022). Power significantly decreased from 0.99 (0.04) during SingleTask to 0.92 (0.05) during DualTask (p=.017). FTSTS concentric, and eccentric impulse significantly increased from 1st to 5th repetition respectively: 0.56 (0.03) to 0.59 (0.03; p=.005), 0.49 (0.03) to 0.56 (0.04; p=.013). Also, standing peak force significantly decreased from 1st repetition (1.39[0.03]) to 5th repetition (1.34[0.03]; p=.004). The mean peak force standing decreased more from 1st to 5th repetition under SingleTask (1.39[0.04] to 1.32[0.03]) compared to DualTask (1.39[0.03] to 1.35[0.03]; p=.044). CONCLUSION: Force characteristics are altered by both dual tasking and number of repetitions during the FTSTS task in healthy, young adults.
Listed In: Biomechanics, Physical Therapy