What exercise is bad for knees?

If you have mild to moderate pain in your knees due to osteoarthritis, walking and other exercise helps mobilize your joint fluid and lubricate the joints. You shouldwalk and do other exercises that move your knee joints. ... If you have moderate to severe pain in your knees before you start walking, take it easy.

http://www.myhealthtipstoyou.com/3-exercises-for-quadriceps/