Related Experiment Videos
Functionally relevant thresholds of quadriceps femoris strength
Lori L Ploutz-Snyder1, Todd Manini, Robert J Ploutz-Snyder
1Department of Exercise Science, Center for Policy Research, Syracuse University, New York 13244, USA. llploutz@syr.edu
Summary
Identifying quadriceps femoris strength thresholds is crucial for assessing ambulatory function. A strength-to-weight ratio below 3.0 Nm/kg indicates a high risk of impaired mobility in older adults.
Area of Science:
- Gerontology
- Biomechanics
- Physical Therapy
Background:
- Maintaining ambulatory function is vital for independence in older adults.
- Quadriceps femoris strength is a key determinant of mobility.
- Preclinical disability can be identified by subtle declines in functional performance.
Purpose of the Study:
- To determine quadriceps femoris strength thresholds impacting ambulatory task performance.
- To assess the correlation between self-reported function and objectively measured performance.
- To identify individuals at risk for preclinical mobility decline.
Main Methods:
- 100 older adults (mean age 73 years) underwent isometric knee extension strength testing.
- Participants performed chair rise, gait speed, and stair negotiation tasks.
- Strength-to-weight ratio (STR/WT) was calculated and correlated with functional task success.
Main Results:
- Significant relationships (p <.0001) were found between STR/WT and functional performance.
- STR/WT thresholds between 3.0 and 3.5 Nm/kg were identified, below which success likelihood decreased.
- A STR/WT < 3.0 Nm/kg indicated substantial risk for impaired chair rise, gait speed, and stair negotiation.
Conclusions:
- STR/WT thresholds can identify older adults with preclinical disability.
- This ratio is a sensitive and specific predictor of functional success in ambulatory tasks.
- Targeted strengthening interventions can be developed based on these identified thresholds.