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Published on: June 12, 2019
Test-retest reliability of isokinetic knee extension and flexion
Gisela Sole1, Jonas Hamrén, Stephan Milosavljevic
1Centre of Physiotherapy Research at the School of Physiotherapy, University of Otago, Dunedin, New Zealand. gisela.sole@otago.ac.nz
Objective:
To assess reliability of isokinetic peak torque and work for knee flexion and extension.
Design:
Single-group test-retest.
Setting:
University laboratory.
Participants:
Eleven men and 7 women (mean age, 21 y).
Interventions:
Not applicable.
Main Outcome Measure:
Peak torque and work for concentric and eccentric knee extension and flexion were recorded at 60 degrees/s for 3 trials on 2 occasions. Intraclass correlation coefficient model 3,1 (ICC(3,1)), standard error (SE) of measurements, and smallest real differences were calculated for the maximum and for the mean peak torque and work of the 3 repetitions.
Results:
Relative reliability was "very high" for peak torque and work (ICC range, >.90). The SE measurements ranged between 5% and 10% of the initial values for both peak torque and work. The smallest change that indicates a real improvement for a single subject (smallest real differences) ranged from 12% to 25% for peak torque and work variables and from 25% to 30% for the peak torque ratios.
Conclusions:
Isokinetic concentric and eccentric knee extensor and flexor strength variables are reliable when measured by the same examiner in asymptomatic subjects.

