Question

Why is the leg kept flexed at 30 degrees?

Answer 1

The flexion active normal range for knee is from 0 degree extension to 140 degree flexion for active range of motion. People with flexion deformity or in case of knee injuries the active motion range is reduced. So for such clients or patients the motion range is kept flexed at 30 degree for quadriceps and hamstring co-contraction in a closed chair position to maintain stability at 30 degree mark. The 30 degree flex also helps with the avoiding knee knocking, vulgus landing incidences and also provides additional stability with soft landing.