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Do knee injuries have long-term consequences for isometric and dynamic muscle strength?
H M Holder-Powell1, G Di Matteo, O M Rutherford
1Applied Biomedical Research Group, GKT School of Biomedical Sciences, Kings College, London, Guy's Campus, London SE1 1UL, UK. heather.holder-powell@kcl.ac.uk
European Journal of Applied Physiology
|September 19, 2001
Summary
Knee extensor muscle strength deficits persist long after traumatic knee injuries, especially in eccentric contractions. These strength impairments are influenced by the type of muscle activity and injury dominance, not time since injury.
Area of Science:
- Orthopedics
- Sports Medicine
- Rehabilitation Science
Background:
- Traumatic knee injuries, including ligamentous and meniscal tears, can lead to long-term functional deficits.
- Persistent weakness in knee extensor muscles may impact athletic performance and daily activities.
- Understanding the factors influencing persistent strength deficits is crucial for effective rehabilitation.
Purpose of the Study:
- To investigate the long-term persistence of knee extensor muscle strength deficits after traumatic knee injuries.
- To analyze how muscle strength decrements vary based on the type of muscle contraction (isometric, concentric, eccentric).
- To examine the influence of injury dominance (dominant vs. non-dominant limb) and time since injury on strength deficits.
Main Methods:
- Assessed 36 individuals with previous unilateral traumatic knee injuries.
- Measured peak voluntary quadriceps muscle strength using a dynamometer during isometric, concentric, and eccentric contractions.
- Compared strength between injured and uninjured limbs and analyzed differences across contraction types and injury characteristics.
Main Results:
- Significant quadriceps muscle strength deficits were observed in the injured limb across all contraction types (isometric, concentric, eccentric).
- Concentric and eccentric contractions showed greater strength decrements compared to isometric contractions within the injured limb.
- Eccentric strength deficits were more pronounced in the dominant limb compared to the non-dominant limb; time since injury did not correlate with decrement severity.
Conclusions:
- Quadriceps muscle strength deficits persist long after traumatic knee injuries, rarely returning to pre-injury levels.
- The type of muscle activity significantly influences the degree of strength decrement, with eccentric and concentric contractions being more affected.
- Rehabilitation strategies should consider the specific deficits related to contraction type and limb dominance for optimal recovery.