Does weight training your quads affect your knees?

Answer 1

Not necessarily. Of course, if you exercise improperly (such as bouncing at the bottom of a squat, in my opinion) you may injure your knees. Even assuming that you exercise properly, after several decades of training your knees may hurt a bit during exercise. This does not happen to everyone. If you always warm up properly and use perfect exercise technique, it may never happen to you. Exercise selection, too, is important. For example, it is a good idea never to do heavy leg raises because they really stress the knees.

Even if your knees eventually hurt during training, there may be ways to work around it. For example, if regular back squats hurt your knees, switch to box squats. Box squats are much more difficult, which means that you will use less weight; using less weight means less stress on your knees.