5. Leg Extensions
The leg extension machine is inherently bad, so all people should avoid them. Knees aren’t designed to fully extend while moving weights. The angle is abnormal and that adds to the wear and tear on your knees.
Adding weights just increases the chance of damaging knees. Young athletes who use these machines often find themselves developing chronic knee pain as they age.
Knees age badly, so avoid this machine and encourage your young workout companions to avoid it as well.
4. Leg Press
Along with the leg extension, the leg press is a machine you should avoid. It is hard on your knees and back as a young athlete. As an older athlete, back and knees will pay the price of using this machine. It can be hard to press forward, especially with heavy weights and keep your back in proper form.
There are kettle ball exercises that will provide the same workout without grinding your knees away and making the small of your back ache.