Muscle injuries occur when muscle fibers are overstretched or torn, often due to excessive force or improper use. Common types include strains, which involve the stretching or tearing of muscles or tendons, and contusions, which are bruises caused by direct impact. Symptoms typically include pain, swelling, and limited movement. Treatment for muscle injuries usually involves rest, ice, compression, and elevation, often referred to as the RICE method. In more severe cases, physical therapy may be necessary to restore strength and flexibility. Preventive measures include proper warm-up exercises and maintaining good physical conditioning to reduce the risk of injury.