Having a good, efficient kick brings benefits to your swim stroke and speed. A strong freestyle kick adds propulsion, making you faster in the water. It also aids in rotation and timing, which are vital in good swim technique. Lastly, an effective and efficient kick helps you maintain good body position, reducing resistance in the water and letting you slip through like a fish.
However, a lot of triathlon swimmers tend to neglect training their kick because it can be exhausting, especially with two other leg-heavy disciplines like cycling and running to train for.
Our resident swimming expert Brenton Ford is here with five tips to a more effective kick.
Do Kick Sets
One of the best ways to develop your kick is just to do more kicking. Brenton says, “There’s no way around developing an effective kick apart from just doing the work and doing some kicking sets in training."
For beginners, Brenton will throw in some 50-meter (or yard) kick efforts using a snorkel or kickboard, and optionally fins. Isolating the kick allows you to understand what is or isn’t working in your kick technique. “If you do have an underwater camera, film yourself when you're swimming so you can see what you're doing in the kick.”
Keep your kick narrow. “If you've got a normal-sized bucket, double that should be roughly where your feet stay in your kick,” says Brenton. Having your legs spaced narrowly during your kick concentrates most of the power in a small space behind you, like a torpedo.
Kicking inside that imaginary bucket also reduces drag, since you’re keeping your forward-facing surface area small. (Reduce drag even further by keeping your legs close to the surface.)
Controlled Knee Bend
The freestyle kick is made of two parts: the up kick where your leg draws closer to the water surface, and the down kick where your leg moves down to propel you forward.
Aside from helping to lift your legs closer to the surface, tensing your glutes also allows for a more effective up kick with a straight leg to prepare for the down kick. Brenton says, “If you are bringing the leg up only by bending your knee, it’s going to slow you down.” Bending your knees to a 90-degree angle creates a lot of drag versus the amount of propulsion you might get from the down kick.
Then keep the knee bend within a small range of motion through the down kick. Brenton notes. “We need to make sure that we are bending the knees the right amount. I've seen people go both ways: one, they’re too straight and stiff with their legs, and the other way is they're bending their knees too much.”
You won’t get much propulsion from kicking with straight legs (knees at a 180-degree angle) because you can’t transfer force from your glutes and hip flexors down your leg in a whip or wave motion.
1500-meter freestyle world record holder Katie Ledecky bends her knees asymmetrically with one leg straight and the other leg kicking with a 130-degree knee bend, according to Brenton. But it seems as if 130 degrees is the Goldilocks range for a knee bend: not too straight, and not too bent. It allows you to keep that narrow kick, but still propels you forward.
Brenton says, “We want the toes to be somewhat pointed back towards the end of the pool behind you.”
This doesn’t mean pointing your toes aggressively like a ballerina: that can actually cause foot cramps. But allowing the tops of your feet to reach away from your shins lets you use your feet like flippers or swim fins and give you more surface that will be pressing down and backwards as you're kicking.
Additionally, dorsiflexed feet with your toes angled towards shin can cause a lot of drag. In fact, if you kick using a kickboard with your toes pointing down, you’ll go backwards!
Many strong runners and cyclists have poor ankle flexibility, but this shouldn’t stop you from plantar flexion (verses “dorsiflexion”). To help you point your toes, turn your big toes towards each other like a pigeon, which gives you more flexion even with tight ankles. When kicking, you can tap your big toes together to remind your body to keep this alignment.
“We want to time the catch on the right-hand side with the down kick on the right-hand side,” notes Brenton. This gets the catch, rotation, and kick all working together in the kinetic chain that makes up the freestyle stroke, propelling you forward more efficiently as well as reducing drag from poor timing.
“If your catch and your kick are happening together, that's the right timing and that is really the key to an effective kick for middle- to long-distance swimmers.”
Brenton Ford is available for MX Endurance members to consult regarding their swim form.