. Author manuscript; available in PMC: 2016 May 23.

Published in final edited form as: Arch Phys Med Rehabil. 2009 Feb;90(2):285–295. doi: 10.1016/j.apmr.2008.08.214

Table 2.

Description of the Impairment Measures Used in the Study, the Technique Used, and the Intertester Reliability for the Measures

Measure	Technique	Intertester Reliability
Quadriceps femoris strength	Measured using an Isokinetic dynamometer^a. The subject was seated with the tested knee flexed to 75°. The subject was instructed to exert as much force as possible using an isometric contraction while extending the knee against the force-sensing arm of the dynamometer. The contraction was repeated for 4 trials, and the trial with the maximum torque was recorded.	ICC above 0.80 in 2 studies.^{84 and 85}
Hip abduction strength	Measured with a hand-held dynamometer^b with the subject side- lying with the tested hip positioned superior in relationship to the nontested hip.⁶³ The subject exerted an isometric contraction of the hip abductors against the resistance of the dynamometer positioned proximal to the lateral malleolus. The average force of 2 trials with 1 minute of rest between trials was recorded.	ICC=0.85.¹³
Hip external rotation strength	Measured with the hand-held dynamometer. Subject was lying prone with the tested knee flexed to 90° and the hip in neutral rotation. Subject exerted an isometric contraction of the hip external rotators against the resistance of the dynamometer positioned just proximal to the medial malleolus. The average force of 2 trials with 1 minute of rest between trials was recorded.	ICC=0.79.¹³
Hamstrings length	Determined using the straight leg raise test with the subject lying supine.⁶⁴ The lower extremity was passively lifted to the firm end feel. Angle of the straight leg raise test was measured with a gravity goniometer^c placed over the distal tibia. The average measurement of 2 trials with 5-second pause between trials was recorded.	ICC=0.92.¹³
Quadriceps femoris length	Determined by measuring passive knee flexion using the gravity goniometer placed over the distal tibia with the subject in the prone position. The average measurement of 2 trials with 5- second pause between trials was recorded.	ICC=0.91.¹³
Plantar flexors length	Measured with a standard goniometer with the subject in prone. We measured the amount of ankle joint dorsiflexion with the knee extended and again with the knee flexed at 90°. Ankle dorsiflexion measured with the knee extended was used to account for the influence of gastrocnemius tightness. Measurement of ankle dorsiflexion with the knee bent was used to detect tightness of joint capsule or soleus muscle. The average measurement of 2 trials with 5-second pause between trials was recorded.	With knee extended ICC=0.92.¹³ With knee bent ICC=0.86.¹³
ITB/TFL complex length	Determined by using the Ober test.⁶³ A gravity goniometer was placed over the distal portion of the ITB/TFL complex to record the result of the test as a continuous variable. The gravity goniometer was zeroed on a horizontal surface prior to the measurement. Negative values represented more tightness, whereas positive values (below horizontal) represented less tightness. The average measurement of 2 trials with 5-second pause between trials was recorded.	ICC=0.97.¹³
Lateral retinacular structures length	Assessed with the patellar tilt test.⁷² The examiner attempted to lift the lateral edge of the patella from the lateral femoral condyle with the subject in supine and the knee in full extension. The inability to lift the lateral boarder of the patella above the horizontal plane indicates a positive test for tightness. Lateral retinacular length was recorded as tight or normal.	κ=0.71.¹³
Foot pronation	Measured by the navicular drop test as the difference in millimeters between height of the navicular at subtalar joint neutral position and that of the relaxed stance position.^{86 and 87}	ICC=0.93.¹³
Q-angle	Measured with a standard goniometer as the angle formed by the intersection of a line from the anterior superior iliac spine to the center of patella with a line from the center of the patella to the tibial tubercle⁷⁶ with the knee in full extension.	ICC=0.70.¹³
Tibial torsion	Measured with the subject prone on a low table, and with the tested knee bent at 90°. The examiner measured the angle formed by the axis of the knee (imaginary line from the medial to lateral femoral epicondyle) and an imaginary line through the malleoli.^{88 and 89}	ICC=0.70.¹³
Femoral anteversion	Measured with the Craig test with the participant in prone with the knee flexed to 90°.⁶⁴ The degree of anteversion was estimated based on the angle of the lower leg with the vertical when the most prominent portion of the greater trochanter reaches the most lateral position or the horizontal plane.	ICC=0.45.¹³
Quality of movement	Measured by visual observation during the lateral step-down test. The subject stood on a 20-cm-high step. The tester kneeled 1m in front of the subject and observed the task. The subject bent the tested knee until the contralateral leg gently contacted the floor and then re-extended the knee to the start position for 5 repetitions. The tester scored the movement according with the use of arm strategy (if subject used an arm strategy in an attempt to recover balance, 1 point was added), trunk movement (if the trunk leaned to any side, 1 point was added), plane of pelvis (if pelvis rotated or elevated one side compared with the other, 1 point was added), medial deviation of the knee (if the knee deviated medially and the tibial tuberosity crossed an imaginary vertical line over the second toe, 1 point was added, or, if the knee deviated medially and the tibial tuberosity crossed an imaginary vertical line over the medial border of the foot, 2 points were added), and steadiness of unilateral stance (if the subject stepped down on the nontested side, or if the subject wavered from side to side on the tested side, 1 point was added). Total score of 0 or 1 was classified as good quality of movement, score of 2 or 3 as medium quality, and score of 4 or above as poor quality of movement.	κ=0.67.¹³

Abbreviations: ICC, intraclass correlation coefficient; κ, Kappa.