Different exercises produce different impacts on the knee joints. The best and safest exercises causing minimum impact on the knee for patients post knee replacement or knee arthritis are walking, biking, hiking, riding an exercise bike, riding an elliptical trainer and walking on the treadmill. In sports, one can play doubles tennis and not singles. One can also participate in downhill or cross-country skiing.

The maximum stress-producing exercises are jogging and golf swings.

Impact

Biking produces the minimum force, yielding an impact of about 1.3 times the person’s body weight.
Treadmill walking is next best, producing forces of 2.05 times the body weight.
Walking on level ground generates forces of 2.6 times the body weight.
Playing tennis generates forces of 3.1 to 3.8 times the body weight; serving produces the highest impact.
Jogging produces forces of 4.3 times body weight.
Golf swings produce forces of 4.5 times body weight on the forward knee and 3.2 times body weight in the opposite knee.