Final answer:
A muscle strain occurs when a muscle or tendon is stretched beyond its elastic limits, causing damage and tears to the muscle fibers.
Step-by-step explanation:
A muscle strain occurs when a muscle or tendon is stretched beyond its elastic limits. This means that the muscle or tendon is stretched to the point where it becomes damaged and tears the muscle fibers. Strains are often painful and can result in stiffness and bruising in the affected area.
For example, if someone lifts a heavy weight without proper warm-up or preparation, they may strain their bicep muscle by overstressing it. A muscle strain occurs when a muscle or tendon is stretched beyond its elastic limits, causing damage and tears to the muscle fibers. This can lead to pain and difficulty in moving the arm.