It's important because,if you don't tears and strains will occur in the muscles. That's why keeping your muscles healthy will also help you enhance your performance and allow you to gain more muscle strength. Also, Healthy muscles let you move freely and keep your body strong. Healthy muscles let you move freely and keep your body strong. Strong muscles also help to keep your joints in good shape. If the muscles around your knee, for example, If you get weak, you may be more likely to injure that knee.