Table 4 Joint flexibility tests and references from typically developing controls attained in other studies

Modified Thomas test

 Hip measurement 1: Hip angle > 0° = short and/or stiff one-joint hip flexors (i.e. iliopsoas, hip adductors).

 Hip measurement 2 (examiner applies hip extension torque): Hip angle > 0° = short one-joint hip flexors.

 Hip measurement 3: Reference value = 0° (i.e. ASIS and patella aligned on the sagittal plane). Positive values = short and/or stiff hip abductors.

 Knee measurement 1: Knee angle < 67° = short and/or stiff two-joint hip flexors (i.e. rectus femoris, tensor fascia latae, sartorius).

 Knee measurement 2 (supported hip): Knee angle < 67° = short and/or stiff two-joint hip flexors.

 Note: Tightness of the anterior capsule and ligaments may also influence the test.

 References: [72, 97,98,99]

Passive knee extension test

 Knee angle > 40° (with the hip at 90°) = short hamstring muscles.

 References: [100, 101]

Passive ankle dorsiflexion test

 Ankle angle < 18° with knee at 0° and 90° = short Soleus muscle.

 Ankle angle < 18° with knee at 0° and ankle angle > 18° with knee at 90° = short Gastrocnemius muscle.

 Ankle angle > 18° in with knee in 0° and 90° = good triceps surae flexibility.

 References: [102, 103].