Internal / External Rotation

Internal and external rotation of the knee is a popular test especially in ski-ing populations. The popliteus and hamstrings muscles play a significant role in rotating the knee (internally and externally) to aid unlocking and locking the knee.

It should be noted that this position stretches the ligaments at t the rear of the knee and can impinge the meniscus (cartilages) at the posterior horns.

This could be the effect you want some patient populations (like ski-ing) but in many cases can lead to injury.

Care should be exercised if using this test.

 Supine Lying position:

In this position there is the increased innate thoracic and pelvic stability (little rotation occurs) but the angle of the knee has to be considered with the knee at 90 degrees results tend to be higher than the other most popular angle 45 degrees.


Lying: in the lying position stabilisation usually involves holding the bed handles. Most manufacturers supply a thigh / calf stabiliser. Use the pelvic strap.


The footplate supplied with the machine should fully stabilise the foot it is likely the foot will pull to dorsi flexion during the test so care should be used to full tighten any straps

Axis of rotation:

The axis of rotation goes from the machine and extends through the center of the calcaneous (see below). To check the alignment simply rotate the foot and ensure the knee does not lift from the stabiliser.

Anatomical zero:

Foot points to roof.

Range of motion:

Large individual variations exist in the amount of movement. The ROM should be between 30-50 degrees internal rotation and 20-40 degrees external rotation. 

Gravity correction:

The effects of gravity are negligible in this position in fact some manufacturers use a counter balance rather than instrumented correction.


Speeds tend to be lower in internal external rotation of the knee with multiples of 30 being common. However, any speed from 30-240 degrees/second could be considered representative of the speed of subtalar movement during walking/running. A mid range speed for ordinary subjects is 45 degrees per second which will offer good results.

Generally it is accepted that speeds of 30 degrees/second and multiples of this should be used.

Knee Internal / External Rotation Protocols:

Muscles involved:

        Hamstrings and Gastrocnemius

Strength Test ProtocolsGeneralPatientsAthletesResearch
Contraction Cyclecon/concon/con con/concon/ecc con/conecc/ecc
Speed/s30 – 603030-18030-180
Trial Repetitions003
Repetitions1010 105
Sets34up to 9
Rest between sets20-30 secs20-30 secs 20-30 secs20 secs
Rest between speeds2 minutes2 minutes2 minutes 2-5 minutes
Rest between sides5 minutes5 minutes 5 minutes 5 minutes 
Feedback nilnil nil nil 
Endurance Test ProtocolsGeneralPatientsAthletesResearch
Contraction Cyclecon/concon/con con/concon/ecc con/conecc/ecc
Trial Repetitions000
Rest between setsN\AN/AN/AN/A
Rest between speeds10-15 mins10-15 mins 10-15 mins10-30 mins
Rest between sides5 mins5 mins 5 mins 5 mins 
Feedback nilnil nil nil 
Strength Exercise ProtocolGeneralPatientsAthletes
Contraction Cyclecon/concon/concon/ecc
Speed/s30 up to 603030-180
Trial Repetitions000
Sets66up to 12
Rest between sets30-60 secs30-60 secs30 secs
Rest between speeds2 mins2 mins2 mins 
Rest between sidesNilNilNil 
Endurance Exercise ProtocolGeneralPatientsAthletes
Contraction Cyclecon/concon/concon/con
Trial Repetitions000
Rest between sets5-10 minsN/A5-10 mins
Rest between speeds10-30 minsN/A10-30 mins 
Rest between sidesNilNilNil
Feedbackbar/pie chartbar/pie chartbar/pie chart


Test the uninvolved or dominant limb first. Extreme care must be taken to not damage the knee in this pattern.


In the knee it is normal to look at the ratio between the right and left sides there should be a 0-10% difference between the sides. Anything beyond this would indicate a muscle imbalance which would be best corrected.

Eccentric results are generally 30% higher than concentric within the same muscle.

Concentric/concentric: internal/external rotation ratio should show a external rotation dominance of 10 percent.

Peak torque occurs in the internal rotators at 20 degrees and in the external rotators at 2 degrees (Hester & Falkel 1984).

Normative values:

All values Pt ftlbs   DominantInternalNon DominantInternalDominantExternalNon DominantExternal
Ostering et al. (1980)knee angleM18-35    
30 deg sec90  89.7102.7101.3111.4
30 deg sec45  78.177.483.281.0
Hester & Falkel (1984)90M18-35    
30   2824.728.225.6
60   25.422.825.624.1
120   2018.520.119.2
PTBW ftlbsLeftInternalLeftExternalRightInternalRightExternal