
Isometric knee extension performed in sitting against resistance from the contralateral leg.
Sit on a chair keeping Hips and knees at 90 degrees angle. Straighten exercising leg to 80 degrees and place the foot of other leg on the straighten leg just above the ankle. Noe straighten the exercising leg against the resistance of other leg. Release the resistance and relax.
Nothing here is a prescription. Your physiotherapist decides which of these are yours, and when.