Experts say that many injuries are caused by weak muscles, or at least muscles that are not ready to handle the specific demands of your sport. This is why people who start a running program for the first time often do well for a few weeks, but then as they add the mileage on, they suddenly start to develop foot or ankle problems, hamstring soreness or perhaps lower back pain. Their bodies simply are not strong enough to cope with the demands of the increased training load. For this reason, it is always wise to couple resistance training with regular strength training.
It doesn't have to be extreme lifting, but the basic idea is that your stress out your joints and tendons if you don't have the muscle support to meet the demands of your activity. Strong legs may reduce your chances of having a bad knee etc. Just like everything else in life-- moderation!