Leg workout for knee injuries

Sat on a bank or chair with your legs bent at 90 degrees, raise the foot of your injured knee til the leg is straight. Hold for 3 seconds and repeat 10 times. Then, do the same routine with the foot bent inwards. Then, the same with the foot pointing out. Rest one minute and start again. Another minute and one last round. In a few consecutive days, the improvement will be obvious.