If my 78 yr old father just had both knees replaced, what should he use to strengthen the rest of his legs?

Quad exercises: After a knee replacement, most patients will have quad inhibition and weakness. He can improve the situation by strengthening the quad muscles. Exercises like straight leg raises, stationary bicycle, and slow stair-walking will not harm the knee and can relieve symptoms. His therapist will likely be working on all these already.

Exercise: Exercises directed at strengthening the quads and hip abductors such as waking, cycling and swimming will have the best overall effect.

Post tkr: There r a variety of standard post op protocols to advance ones thigh and leg muscle strengthening. Typically one is given direction with sequential monitoring by a physiotherapist for 3-4 months.Your surgeon should be able to provide appropriate direction.