Cross training is imperative for good knee health. Cross training is athletic conditioning or drillsemploying different activities, mixing, for example, a central activity with one that rests, orunloads, the body from stresses of the main activity.
When we were hunters-gatherers, our physical activities were very diverse. As modern-day foragers more likely to graze in a mall than in a field, we don′t get enough exercise in our normal routines, so we need to exercise perhaps not to accomplish necessary work but maybe still to survive! However, any specific exercise if done repetitively can cause an overuse injury. Pain on the inside of a knee can be just overuse–"runner′s knee" or "breastroker′s knee."
The treatment I prescribe for overuse is what I call "cross training" or "active rest." You need to stay active but need to rest the area that takes the most stress in the primary activity. Activities fall into weight-bearing and non-weight-bearing categories.
If your main activity is walking or running, you need a cross training activity that is non–weight bearing such as swimming or biking. Some activities are closed-chain and minimally weight bearing (Nordic Track, stair stepper, leg press).
This is a section from Dr. Jack E, Jensen’s book The One Stop Knee Shop. Read the next section Beating the Weekend Warrior Syndrome.