Sit-to-Stand Power Is a Stronger Predictor of Gait Speed than Knee Extension Strength

Area of Science:

• Gerontology
• Musculoskeletal Health
• Biomedical Engineering

Background:

• The aging population necessitates reliable methods for assessing physical function.
• Objective physical function, particularly gait speed, is a key indicator of health and mobility in older adults.
• Current assessments of muscular function require comparison for clinical utility.

Purpose of the Study:

• To compare isometric knee extension strength (KES) and sit-to-stand (STS) muscle power in predicting objective physical function (gait speed) in aging adults.
• To evaluate the relative effectiveness of KES and STS power as indicators of mobility in older adults.
• To determine the most suitable muscular function assessment for primary care screening.

Main Methods:

• Cross-sectional study involving 84 aging adults (mean age 66.6 years).
• Measurements included relative isometric knee extension strength (KES) and sit-to-stand (STS) muscle power.
• Objective physical function was assessed via usual gait speed (UGS) and fast gait speed (FGS).
• Multiple linear regression analyses were used to examine associations.

Main Results:

• Both KES and STS power were independently associated with UGS and FGS when analyzed separately.
• In a combined model, STS power remained significantly associated with both UGS and FGS.
• KES was only significantly associated with FGS when both measures were included in the same model.

Conclusions:

• Sit-to-stand (STS) muscle power appears to be a more robust indicator of overall physical function, including gait speed, in aging adults compared to isometric knee extension strength.
• The findings suggest that STS power is a valid measure for assessing functional status in older individuals.
• The feasibility of using STS power as a primary care screening tool for identifying "low" physical function in aging adults warrants further investigation.