Conceptual framework for the associations between trunk and lower limb muscle parameters and physical performance in...

Muscle status plays an important role in the achievement of good physical performance. However, which muscle group and muscle parameters are associated with different physical tasks is not well defined.

To determine the association between trunk and lower limb muscles and physical performance in community-dwelling older women.

118 older women, underwent an evaluation of physical performance, i.e., gait speed, Timed Up and Go (TUG), 5-times stand-to-sit (5TSST), forward and lateral step, and tandem gait, as well as a muscle performance evaluation with an isokinetic dynamometer to obtain the peak torque (PT), rate of torque development (RTD), and torque steadiness (TS) of the trunk, hip, knee, and ankle.

There were associations between physical performance and muscle variables. However, each physical task was associated with different muscle parameters. Gait speed is the motor task that requires the least muscle strength (i.e., PT), whereas 5TSST, forward and lateral steps require PT, RTD, and TS of different muscle groups. Lower limb muscles RTD also plays a role in TUG and gait speed performance. The ability to control a submaximal torque is mainly required for forward and lateral stepping tasks. The PT of trunk muscles is also important for better performance of clinical tests.

This conceptual framework may be a guide for the understanding of the association between physical performance and trunk and lower limb muscle functional parameters in older women and may help future longitudinal research to confirm causality and assist physical therapists in decision-making.