힘줄, or "tendons," are strong, flexible tissues that connect muscles to bones in the human body. They play a crucial role in movement by transmitting the force generated by muscles to the skeleton, allowing for coordinated actions like walking, running, and lifting. Tendons are made primarily of collagen, which gives them their strength and durability. Common examples of tendons include the Achilles tendon, which connects the calf muscles to the heel bone, and the patellar tendon, which connects the thigh muscles to the kneecap. Proper care and conditioning are essential to maintain tendon health and prevent injuries.