How can I improve the efficiency of my kick in swimming?

Question

In training, I really struggle with front/back crawl or fly kick exercises.

Not only do I not get much propulsion but the little I do get pretty much drains all my energy and leaves me gasping for breath.

My question is: if you have also struggled with this at some point, ie. you are a competent swimmer but the vast majority of your ability comes from upper-body strength, what exercises and quantity of those exercises (in or out of water) did you use to improve?

Answer 1

It comes down to a couple things.

• Ankle flexibility is huge. Your ankles are what creates propulsion in your kick. Not your thighs, not your calves. Your ankles. The more flexible they are the more water they push back (and not down, as is typically practiced).
• Kicking and swimming with a narrow profile. Most swimmers feel like they have to kick big and wide. All you are doing is creating a heap of drag that your upper body has to try and pull against. Get your hips up. Aim to have a narrower profile in the water.
• Leg fitness. The unavoidable part of the equation is simply having stronger and fitter legs. This means doing lots of kick. Not more running, more biking, but actual miles on the kickboard. Throw in some vertical kicking (my favorite), or some other kick drills to mix things up, but ultimately if you want a stronger, faster kick you gotta kick more.
• Kicking with short fins might help a little bit, particularly in giving you a little bit of ankle flexibility, but they tend to be a crutch. As mentioned before, if you want a better kick, kick more.

About me: National level swimmer, Olympic Trials qualifier. :32 second/50m kicker.

Answer 2

When I started swimming I had the same problem. I come from an ultra running background so I had very little flexibility in my ankles and poor technique. The following worked for me:

• do lots of stretching to get some flexibility back in my ankles. You must try to point your toes to the back and not down; Take a look at this page http://www.feelforthewater.com/2013/03/ankle-flexibility-with-olympic-medalist.html
• do you bend your knees excessively when kicking? I had to stop myself from bicycling under water instead of doing a proper kick where you keep your legs as straight as possible (but don't go too far and lock your knees)
• do you keep you legs together? In the front crawl I used to regularly do a scissor kick which causes drag and costs energy. I spent a lot of time focussing on keeping my legs together at all times. You can try brushing your big toes against each other when kicking.

The best tool I found for correcting these problems was swimming with flippers. Here you feel right away when your foot is not correctly aligned and when poor technique is causing more drag (and hence costing more energy). A good exercise for me is 300m front crawl with flippers and then 300m without but trying to keep the same kick.