Do butterfly to develop endurance and strength.
For a non-IM'er, the individual medley is a daunting, scary event, incorporating all four strokes (butterfly, backstroke, breaststroke, freestyle).
In competition it's either an explosive, adrenaline-filled 200-meter distance, or a brutally painful, endurance-testing 400 meters (although some swimmers will swear it must last 800 or 1,600 meters by the time they finish).
Swimmers who favor only one stroke (and you triathletes also know who you are) are missing out on an opportunity to cross-train in the pool by swimming a medley of strokes that have many beneficial effects.
Although I compete in long-distance ocean races that require only freestyle, I continue to train in all four strokes year round and I am a firm believer that it makes me a better distance swimmer.
This article will outline the four strokes and offer ideas on how to incorporate them into a daily swimming routine to better your overall swimming performance.
Butterfly is closely related to freestyle in that it is basically the same stroke, only both sides of your body are doing a mirror image of each other at the same time (whereas in freestyle they alternate).
Considered to be the most difficult stroke, butterfly is often shunned and ignored by swimmers who fear the pain they'll endure after a few laps. However, butterfly develops strength and stamina while simultaneously testing your cardiovascular ability (see if you aren't breathing hard even after a few easy laps!).
By incorporating fly into your workout every time you step into the pool, your favored strokes will feel easier and you will notice that the same muscle groups you use in freestyle and breaststroke are being strengthened thanks to the butterfly. One challenge you can try is swimming the last lap of each of your sets butterfly (for instance, if you are swimming 5x100 on 1:30, do the last 25 butterfly).
By swimming this difficult stroke at the end of a hard set or workout, you can simulate end-of-race fatigue and condition your body to better handle such stress (try it and you will see what I mean!).
Backstroke is a great recovery stroke. You should always swim some backstroke in your warm-up and your cooldown every day. It allows you to stretch out your chest and lat muscles while giving you ample opportunity to breathe when you want because you are not face down in the water as you are in the other three strokes.
After a hard set it is wise to do 100 or so meters on your back, and let your heart rate subside with active rest (meaning that you are actively resting by swimming easy); you'll keep your muscles moving and prevent lactic-acid buildup.
Breaststroke was always my weakest stroke, but it was a terrific way for me to stretch—and use—my leg muscles. Freestylers (read: triathletes!) will neglect their legs in practice because it is simply impossible to six-beat kick for the duration of an entire workout. However, a few hundred meters of breaststroke flex your groin, thigh, and calf muscles and keep your legs limber and flexible.