• McPherson AL
• Kunzer CM
• Bates NA
• Schilaty ND

• Knee / physiology
• Lower Extremity
• Muscle Strength Dynamometer
• Open Access Document

Objectives: Develop a protocol to assess isokinetic concentric knee flexion and extension testing at three different velocities.

Methods: Ten subjects were each assessed on two test days by two clinicians. Clinicians followed a protocol developed to ensure consistency in subject set-up on the isokinetic dynamometer. Knee flexion and extension were assessed at three different velocities. Average peak torque, angle of peak torque, and total work for both the quadriceps and hamstrings muscles were assessed for reliability, via intra-class correlation coefficients (ICC), between testers and between days. Limb symmetry indices (LSIs) were also calculated and compared between testers and between days.

Results: Intra-rater reliability varied; peak torque, for both muscles, had moderate reliability for both clinicians [ICC(3,1) ≥ 0.669 (95% CI: 0.546-0.773)], total work was good to excellent for both clinicians and had the highest reliability values for all variables of interest [ICC(3,1) = 0.813 (95% CI: 0.731-0.877)]. Inter-rater reliability ranged from poor to moderate depending on the variable; total work had the highest reliability for both the quadriceps and the hamstrings, whereas the angle of peak torque had the lowest inter-rater reliability for both muscle groups. Limb symmetry indices for peak torque and total work were not significantly different between clinicians (p=0.72 and p=0.94, respectively).

Conclusion: The findings of this study demonstrated that testers who are trained and familiar with isokinetic dynamometer testing set-up and protocols prior to performing assessments on patients may help to minimize the effect set-up may have on output measurements.

Author keywords: lower extremity, dynamometer, flexors, extensors

This abstract is reproduced with the permission of the publisher. Click on the above link for free full text.