The quadriceps are the most surprising of the unstretchables, because everyone has done a quadriceps stretch, and you probably think you “know” that they can be stretched. However, you were only stretching the rectus femoris muscle — about 10–15% of the mass of the group. It feels like a strong stretch, and it is of that tissue. But the other 85–90% remains only mildly elongated. The quadriceps consists of four muscles, the skinny rectus femoris and the three huge “vasti” — vastus lateralis/intermedius/medialis. The vasti are only elongated by knee flexion, which is limited to about 120˚ when the calf hits the hamstrings.
- Quadriceps! (rhvillegas.wordpress.com)
- Procedure can treat stiff-knee gait in spastic cerebral palsy (medicalxpress.com)