Fins should be part of every serious swimmer's gear bag, for better drills and building strength and flexibility.
David De Lossy/Photodisc/Getty Images
After goggles, fins are probably the most important accessory for swimmers. Their primary use is to help you do drills more effectively and efficiently. During drills, fins help with body positioning and they help you focus on efficient kicking. They also help increase leg strength and ankle flexibility. In other words, fins aren't just there to make you go faster.
For swim workouts, you usually want a short-bladed fin, especially if your preferred stroke is freestyle or backstroke. Short fins require a faster kick, help develop your kicking tempo and keep your feet from kicking too big or too wide. Long fins are more for distance swimming since they provide more resistance and, hence, produce a slower kick. Because the kick is slower, there is not the instant feedback that short fins provide. There are also mono fins, which keep the feet together. These are specialized for the breaststroke and rarely used by other swimmers.
Fins and Body Positioning
Using fins helps you focus on body positioning and upper-body technique without having to think about propulsion. Decreasing resistance is always the first step in getting faster, so as you concentrate on streamlining your body in the water, fins maintain your forward motion. Some fins also help float the feet, giving you the higher body position in the water you want.
Fins and Leg Strength / Ankle Flexibility
Fins help build strength in the legs and improve the kick by helping create better ankle flexibility. Fins stretch the ankle more than kicking with a bare foot alone, which increases the joint's mobility. The larger surface area you're kicking with also increases load on the leg muscles. Swim coach and Total Immersion Swimming founder Terry Laughlin calls swimming with fins the вЂњwet weight workout.вЂќ
When to Use Fins
Fins are used during warm-up drills, but typically not during your main workout. If you're a general fitness swimmer with no performance goals, wearing fins consistently is fine, though swimming without them makes for a more difficult workout. For competitors and fitness alike, use fins to help with body position and stroke improvement, then start to swim more and more with bare feet. Continue using fins for your drills and take them off for your main workout. One important caveat is to avoid swimming with fins if you have an ankle, knee or leg injury. Fins may put additional torque on a body part that can't handle it.