Bodybuilding has been around for a long time, so it makes sense that some go-to exercises have found their place in the gym. But today we have the technology and experience to avoid what really hurts us and adapt to what works best. Here is a list of the major back and joint injuries that everyone does, but shouldn't. 1) LEG EXTENSIONS The weight is based on the ankles, so the torque applied to the knees is significantly higher than what you are actually lifting and causes undue stress on joints and tendons. Instead: Reverse lunges keep the weight on the muscles and don't transfer it to the joints (that's the problem with machine exercises in general). 2) BACK SQUATS This is a very controversial topic, so I'll refer you to a legitimate professional accepted all over the world. “After a certain point, your lower back doesn't allow you to transfer strength to your lower half... it's the weak link, preventing your lower body muscles from producing maximum work capacity.” - Mike Boyle - world renowned strength coach and men's health training consultant. Instead: highly recommended instead of bac...