Ankle sprains occur when the ligaments in the ankle are stretched or torn, usually from a sudden shift in movement. Symptoms include swelling, tenderness, and bruising. People who have previously sprained their ankle are at higher risk of re-injury. To prevent ankle sprains and re-injury, regular stretching, strengthening, and balance exercises are recommended to improve flexibility, strength, and proprioception in the ankle. A study found that athletes who did home proprioceptive training after an ankle sprain were less likely to suffer re-injury within a year compared to those who did not do home training.