Sitting Knee Flexion (Long Arc Quads)

Phase I

Sit in a chair or on the edge of the bed with back straight and legs bent. 

Bilateral shoulder girdle is in neutral
Bilateral shoulder joint in neutral

Phase II

Extend the knee as far as you can to make the leg straight.
Agonist Muscles used in extending the knee.

rectus femoris contracts concentrically to extend knee.

vastus intermedius contracts  concentrically to extend knee.

vastus lateralis contracts concentrically to extend knee.

vastus medalis contracts concentrically to extend knee

Phase III

 Go back into the original position by flexing the knee.

Agonist muscles used to flex the knee. 

Bicep femoris contracts eccentrically to control flexing of the knee.

popiteus contracts eccentrically to control flexing of the knee.

semimembranous contracts eccentrically, to control flexing of the knee.

            semitendinous  contracts eccentrically to control flexing of the knee

Drill

1 - Stand with your right foot forward and left foot back, a step width apart and toes pointing ahead.

2 - Slightly bend your right knee (moving your weight forward), keep your left knee straight and heels on the floor. Facilitate this stretch by leaning on a wall directly in front of you. Gently push against the wall whilst doing the stretch described above.3 - Feel the stretch in your left calf.

4 - Repeat by switching legs.