The TOP 5 reasons to use FINS during Swimming workouts

1)  Improve Body Position and Technique

One of the greatest benefits of using fins is the ease of holding a better body position. This allows swimmers to focus on other parts of the stroke technique, such as arm position, body rotation or timing.

2)  Develop Leg Strength
Kicking with fins is like lifting weights: the added resistance of the water on the blade of the fin increases the workload on your leg muscles. Your body adapts by increasing the strength and endurance of the muscles involved. Stronger muscles move more water making you swim faster, all other things being equal.

A word about specificity: It's important to realize that muscular strength for swimming needs to be "specific." Good runners, cyclists, roller bladers, etc. can have very strong leg muscles, but the muscles have developed for running, cycling or roller blading, not for swimming. Fins develop leg strength specifically for swimming, and in a way that few other activities can.

3)  Increase Ankle Flexibility

Swimmers can hyperextend (plantar flex) their ankles, pointing their toes so that the top of the foot forms a straight line with the shin. Because of the extra load from the increased surface area that fins provide, swimming or kicking with fins forces ankle extension during the power phase (pushing down when swimming freestyle) of the kick. Repeated fin use eventually stretches the ankles, increasing their flexibility for moving in all directions and helping the kick become more propulsive and efficient.

4)  Increase fitness and Cardiovascular Conditioning Although swimming is considered one of the best aerobic or cardiovascular-conditioning exercises, many people forget to use their legs where the largest muscles are located. Since the greatest cardiovascular benefits come from including the highest percentage of the body's muscles - that's why cross-country skiing and rowing are considered two of the most demanding sports - it makes sense that swimmers who activate the large muscle mass of the legs by kicking will benefit from a more demanding workout that burns more calories and increases fitness levels.  Add fins to the equation and the increased load they add to the legs means that as long as exertion levels remain high, the cardiovascular system gets an even more intense workout with even greater fitness benefits.

5)  Fast Swimming!

One of the goals of swimming faster with fins is to swim faster when the fins are taken off! By transferring the feeling of swimming faster and higher with fins to swimming without them, a swimmer makes use of a phenomenon known as neuromuscular patterning. The muscles and the nerves can actually remember the feeling of swimming faster and will try to duplicate the pattern the next time out. The more times the pattern is repeated (swimming faster and higher in the water with fins), the easier it is to duplicate it. The end result: the swimmer's technique and neuromuscular coordination improves.

What kind should I buy and how can I tell if they fit?

Fins should be snug fitting but not too tight. If you can't find the right size, get the slightly larger ones and wear socks with them.

Fin sizes

Regular sized fins are great for beginners and people who need to develop ankle flexibility.

Link to an example of this fin at Elsmore aquatics:

http://www.elsmoreaquatic.com/cgi-bin/store/agora.cgi?cart_id=5402758.27083*wL8tB0&p_id=TR112&xm=on&ppinc=search2

Medium bladed fins offer more power form each kick.  They are great for working on dolphin kick and butterfly or breaststroke. You can feel your body and leg movements as you swim - the bigger fin adds emphasis, amplifying each kick.  Recommended for the more experienced swimmers.

Link to an example of this fin at Keifer aquatics:

http://www.kiefer.com/Kiefer/productr.asp?pf%5Fid=800080&gift=False&0=dept%2Easp%2Cdept%5Fid%3D88%26Tree%3D%2CCompetitive%20Swim&1=dept%2Easp%2Cdept%5Fid%3D5%26menu%5Fid%3D%26Tree%3D0%2CTraining&2=dept%2Easp%2Cdept%5Fid%3D48%26menu%5Fid%3D%26Tree%3D1%2CFins&HSLB=False&mscssid=16A823FDCE114EB09183D46926405792

Avoid long bladed or vented scuba style fin. While excellent for scuba uses, they are not the best choice for swimming workouts. Their length and design result in very slow movements, too slow to give you as much specific benefit as the shorter variety. They still offer some benefits, for flexibility, increased workout load, and speed, but not as many as the shorter or medium bladed variety.