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by Terry Heggy

April 1, 2015

What runners and cyclists need to know for effective swimming

Experienced runners and cyclists have strong legs and excellent lower-body endurance. Therefore, it’s only natural to assume that your legs will provide an advantage in swimming. It makes sense to apply most of your energy toward a powerful kick when you race in the water. Doesn’t it?

Well, no. I’m afraid it’s exactly the opposite. Allocating the majority of your energy to the legs is probably going to have a negative impact on your triathlon results. Let’s review Water Physics 101:

  • The more space you take up in the water, the more resistance (drag) you have to overcome. A large kick can create a lot of drag while generating very little propulsion.
  • With flutter kick, your legs can only create propulsion through up and down motions, which creates thrust by deflecting the water off your feet. Your arms, however, can actually grab water and propel you forward, which is a much more efficient way to generate thrust.
  • Many runners and cyclists do not have good ankle flexion. If you can’t point your toes, the entire foot contributes to drag—and the harder and deeper you kick, the more resistance you create.

Does that mean our legs are useless in the swim? Oh no, far from it—strong legs are still an asset! We just need to implement a few strategies to take the best advantage of them.

Load Up Your Toolbox

  • Get a good wetsuit and let it support your legs so that you can apply your kick power with an economical motion. (Don’t kick any deeper than your hips.) Once you’ve learned good body position and kick technique, lock it in so you feel exactly the same during your nonwetsuit training swims.
  • Leverage your learning resources. Read articles, watch videos, and get a good coach to help you minimize your drag profile. Master good posture and position.

Balance Your Portfolio

Someone racing a 50 freestyle in a swim meet uses all available energy in both the arms and legs, and expects to be completely spent in just a few seconds. But a triathlete needs to understand how energy allocation should change throughout a triathlon, and plan the race accordingly.

  • Your leg strength and speed will come in handy on a beach start, and during the run out of the water to the transition area. Practice those sprints as part of your training routine.
  • For most of the swim, though, you want to allocate the vast majority of your energy into your arms. Let the legs rest up for the bike and run.

Let’s Get Flexible

Even though you’ll be focused on upper-body power during the swim, it’s still critical to have good kicking technique, and that requires ankle flexion.

  • Assess your flexibility by lying on your back with your legs straight and heels on the ground. Push your toes away from your torso and see how far down they go. Many world-class swimmers can almost touch their toes to the floor, but for most of us, just being able to get the top of the foot parallel to the shinbone is pretty good. If your toes only point to the ceiling, well, your flutter kick is going to suffer.
  • Stretch your ankles by gently pressing the toes into that pointing position and holding it for at least 30 seconds. CAUTION: Avoid stretches that put stress on your knees (e.g., sitting on your feet, of pulling up on your feet with excessive force.) Consider getting a friend to use a blanket or pillow to apply gentle downward pressure.
  • When you wear fins in swim practice, feel how the fins help stretch those ankle tendons. Remember, you’re wearing fins to help achieve efficient foot movement, not just to go faster.

Run to the Gym

  • Increase your swim strength by implementing a weight-room program to gain stroking power, especially in your core, lats, and triceps.

Tear Up the Road

By allocating your energy to your upper body during the swim, your legs will have the power you need once you hit dry land. Turn that leg power loose and have fun!


  • Triathlon