The knee extension machine is present in most gyms across the United States. While many people use this machine, many others do not for fear of causing damage to their knees. Why is it that some people fear the knee extension machine? Is it safe to use? Is it a useful tool? Is it “functional” ? This article will teach you why the knee extension machine is safe, why it can be crucial to overcoming knee pain, and how to include it in your exercise or rehabilitation program.