Reproducibility of isokinetic knee eccentric and concentric strength indices in asymptomatic young adults.
OBJECTIVE
To assess the reproducibility of isokinetic eccentric and concentric knee extension and flexion strength indices obtained at two different angular velocities.


METHODS
Cohort study.


METHODS
University human performance laboratory.


METHODS
45 healthy physically active young adults (25 males).


METHODS
A non reciprocal protocol of concentric and eccentric contractions of the knee extensors and flexors was performed at 30 and 120°/s. Strength indices evaluated included peak moment; dynamic control ratios; and the difference between eccentric and concentric ratio at the two angular velocities.


RESULTS
No evidence for inter-test bias in any of the strength indices was noted. Measurement precision for peak moment, as quantified using ratio limits of agreement, suggest that scores may be expected to vary up to 15% for the knee extensors in both eccentric and concentric contraction modes. An error of up to 19% was calculated for the peak moment scores of the knee flexors. Intraclass correlation coefficients revealed fairly robust preservation of participants' rank order for the majority of strength indices (>0.85).


CONCLUSIONS
Isokinetic-related indices of knee muscles performance enable an acceptable level of detection of expected changes in muscular strength parameters as a result of planned interventions.
Human Mobility Research Centre, Syl & Molly Apps Medical Research Centre, Kingston General Hospital & Queen's University, Kingston, ON, Canada K7L 2V7. sivan.almosnino@queensu.ca
Sivan
S
Almosnino
Joan M
JM
Stevenson
Davide D
DD
Bardana
Elena D
ED
Diaconescu
Zeevi
Z
Dvir
D016001:Confidence Intervals; D005080:Exercise Test; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D007866:Leg / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D015203:Reproducibility of Results; D055815:Young Adult