If you add fins in too quickly or use fins too much, you may torque your ankle, especially if your ankles aren’t particularly flexible to begin with. Swim fins are available in a wide variety of styles, colors and designs. In addition, make sure your fins fit properly and don’t rub against your feet as this can cause blisters. Buy swim fins designed for your aquatic activity to improve your performance whether you scuba dive, compete or swim for exercise. Purchase a monofin to improve your dolphin kick or to train for monofin competitive events. Using monofins helps to strengthen your lower back, abdominal, buttocks and quadriceps muscles.