Resumo

Introduction: Age-related weakness results in slow movements, altered motor control, and higher sense of effort during activities of daily living. Thus, when an older adult performs tasks closer to the maximum functional capacity it may contribute to the onset of fatigue and increased risk of falling. Objective: The present study aimed to compare lower limb strength and strength ratio (isokinetic strength/isometric strength) in younger and older adults. Methods: The maximum isometric and isokinetic strength were assessed at hip, knee and ankle joints at sagittal plane. Peak isometric and isokinetic torque were normalized by body mass (Nm.kg-1) and strength ratio was calculated dividing the maximum isokinetic strength over the maximum isometric strength of each joint in each movement. Results: Younger adults had 11.6% higher ankle extension strength ratio (p = 0.013) and 17.6% higher ankle flexion strength ratio (p = 0.001) than older female adults. The isometric peak torque was higher in younger adults than in older adults during all movements tested (p < 0.001). The isokinetic peak torque was higher in younger adults than in older adults during all the movements tested (p < 0.001). Conclusion: This study demonstrated that older female adults had increased functional demand (lower strength ratio) than younger women, which may predispose them to fatigue and increased risk of falling.

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