The type of exercise specifically designed to improve joint flexibility is known as stretching or flexibility training. This form of exercise focuses on elongating the muscles and connective tissues around the joints, which can enhance range of motion and reduce the risk of injury. Popular types of flexibility exercises include static stretching, dynamic stretching, and activities like yoga and Pilates. Regular flexibility training contributes to better posture, increased blood flow, and improved muscle recovery, making it an essential part of a comprehensive fitness routine.