Final answer:
A muscle strain involves the stretching or tearing of muscle fibers, often called a pulled muscle, and is treated with the PRICE method and possibly NSAIDs. Distinguishing a strain from sprains, contusions, and fractures is crucial as each injury affects different tissues.
Step-by-step explanation:
A strain is a stretching or partial tear in a muscle or a muscle-tendon unit. When a strain occurs, muscle fibers tear as a result of overstretching. This injury is also commonly referred to as a pulled muscle or torn muscle. A strain can be quite painful and is associated with symptoms such as stiffness and bruising in the area of the affected muscle. Hamstring strains are particularly common amongst athletes such as sprinters.
First aid for a muscle strain includes the steps represented by the acronym PRICE (protection, rest, ice, compression, and elevation), and medications such as NSAIDs may be used to reduce inflammation and pain. It's important to note the difference between a strain and other injuries such as sprains, contusions, or fractures; as these are injuries to ligaments, skin tissue, or bones respectively, not muscles.