Swim fins are a great way to target your leg muscles in the pool. They help to increase your kick strength, thus making you faster on race day. The length of the fin blade determines the speed at which you are able to kick through the water. The shorter the blade, the faster kick cadence you will be able to do. The longer the fin the more resistance and propulsion in the water. Medium to short blade fins are ideal for swim workouts as they provide you with plenty of resistance while allowing you to maintain a similar cadence to your normal kick, building muscle without putting too much stress on your ankles. Triathlete Sports offers a nice selection of swim fins that will ramp up your swim workouts without robbing your wallet.