- Among older adults, a decline in plantarflexion rate of force development is associated with mobility decline.
BACKGROUND & OBJECTIVE
Declines in the musculoskeletal, neuromuscular, and cardiovascular systems are highly associated with greater dependence on functional mobility and activities of daily living (1). Decline in the musculoskeletal system can be further subdivided into skeletal, muscle strength, muscle mass, and muscle power (2).
Muscle power is the rate of force development (RFD), or change in force / change in time, and it is lost faster than muscle strength (2). Due to multiple functional mobility tasks needing quick force production over a short period of time (i.e. a high RFD), it has been identified that compared to muscle strength, muscle power is a better predictor of independence with functional mobility (2).
Examples of activities that require muscle power include standing up from a chair, walking upstairs, accelerating when walking, and preventing a fall (3). Therefore, it may not be surprising to hear that common methods of assessing muscle power include walking speed (WS), chair stand test, stair-climb time, and timed up and go (TUG) (2).
Unfortunately, during these tests, it is difficult to determine if the limiting factor is muscle power, muscle endurance, or a cardiorespiratory component (3). The objective of this study was to examine the contribution of plantarflexion (PF) RFD and other common tests of muscular performance on the TUG and WS.
It is recommended that plantarflexion RFD is assessed when treating older adults, especially if the patient’s gait speed and TUG are limited