The FAQ listed below are only about the hip power benefits of leg fins. For all FAQ please see the FAQ summary.
Leg fins give a powerful kick from your hips, similar to good barefoot swimming . They encourage less knee-bend. So your knees are higher in the water. These fins guide you into a powerful kick from your hips even if you don’t yet know how to do that. They also strengthen the correct muscles to power your kick.
Regular foot fins make you kick from your knees, not from your hips. This is not the proper way to kick. When you kick from your knees, your thighs slope down in the water and cause drag. You also feel the strain from using your calf muscles too much. Watch people swimming with foot flippers to see how they make you drop your thighs too low, and kick from your knees rather than your hips. That is the style of kick that foot flippers require to work but it is not like good barefoot swimming.
In fact, these problems are also common if you are learning to swim with or without wearing foot flippers. Often, it is very difficult to kick from your hips. No matter how hard you try, you can’t manage it for very long. It is difficult to get rid of bad habits, sinking your thighs and knees too low in the water and kicking from your knees. Foot flippers can really make this problem much worse. If you have used them, they may even have caused your bad habits in the first place.
Leg fins overcome these problems because they attach to your legs. So they lift and straighten your knees. Then you feel the powerful kick from your hips driving your body more horizontally. They teach you how to kick from your hips even if you don’t already know how to do this. And when you take them off, your body remembers this hip powered kick. These fins train and strengthen you for a powerful kick from your hips. This is the correct way to swim freestyle, backstroke and fly.
Now you can have fins that give you extra speed and guide and strengthen a powerful kick from your hips!
Leg fins work the large muscles in your thighs and buttocks. They also work the core muscles in your stomach and torso to stabilise your hip and back (i.e. the core muscles that Pilates exercises focus on). So these fins encourage you to use and strengthen all these muscles.
Foot fins do not use the bigger muscles in your thighs and buttocks so much. Instead, they make you bend your knees too much and work your calves. You can feel your calves and ankles doing most of the kicking with foot flippers. Your ankles get strained and your calves get tired, often cramping up.
Leg fins overcome these problems because they are attached to your legs. They encourage a proper kick from your hips with only a little knee-bend, similar to good barefoot swimming. You use your thighs and buttocks to power your hip joints, supported by your stomach and torso. So these fins give you extra speed powered mainly by your thighs and buttocks. And they tone up your torso and stomach too. Swimming with them strengthens all these muscles.
You still use your calves to bend your knees a little bit with leg fins, but much less than with foot flippers. Calf strain and cramping are much reduced. Your main kick power does not come from knee-bend. Your main kick power comes from your hips.
Now you can have fins that give you extra speed and use the large muscles in your thighs, buttocks, stomach and torso , just like good barefoot swimming!
Leg fins give you constant speed during each stroke, for extra swimming speed overall. This applies to your down kicks, up kicks, and to the transitions between kicks. You need constant speed throughout each stroke (i.e. within each stroke) to optimise your stroke efficiency. These fins do this best for freestyle, backstroke and butterfly.
When you swim with regular foot fins, you can feel the speed changes within each stroke. The speed increases coincide with each down kick. You can feel it and hear it as the water flows past your ears. So regular foot flippers give you a fluctuating speed kick. They do not give you the constant speed within each stroke that you need for maximum efficiency. So foot flippers mess up your entire stroke.
Leg fins do give you constant speed during each stroke because they are attached to your legs . Firstly, your legs are more horizontal and you kick from your hips with only a little knee-bend. Secondly, these fins are designed to flex smoothly towards and away from your legs during your kick. This helps you swim most efficiently, by keeping your speed as smooth as possible throughout your entire stroke. Smooth kicking helps smooth arm pulls. Both together, give you a more consistent speed during each stroke. Even more, your body remembers this constant speed kick, even when you go back to swimming without fins. So swimming with these fins improves your normal swimming too!
For efficient swimming, you need constant speed within each stroke. You achieve this with long smooth arm pulls together with smooth kicking. Listen to the water flow past your ears to measure how consistent your speed is. If your speed is constant, you will hear a smooth and steady sound. If your speed is going up and down during your stroke, you will hear a changing sound.
Now you can have fins that give you extra speed and constant speed during each stroke.
Leg fins give you the correct kick timing with extra speed. They also teach you the proper kick timing and coordination if you don’t already know it. These fins help to coordinate your stroke for freestyle, backstroke and butterfly.
Regular foot fins change your kick timing. You feel their kick power happens over a shorter time, near the end of each kick when your knee moves quickly upwards to push the fin backwards. So, with foot flippers, the kick sequence of your knee and hip movements is completely different compared to barefoot swimming. You can feel it. Foot flippers disrupt your overall stroke timing, arms too.
Leg fins overcome these kick timing problems because they fit on your legs. They guide your hip and knee joints to bend and straighten with a similar sequence to good barefoot swimming. So they deliver power smoothly over a longer time, like good barefoot swimming. This gives you a more continuous and smoother kick. They strengthen the correct kicking muscles whilst using the correct kick sequence. This improves your normal barefoot swimming too, because your body remembers the correct kick pattern.
You can also use them to work on your overall stroke timing to improve your freestyle, backstroke and fly. They help you to coordinate your arms and legs properly. For example, you can use their smooth, continuous kick to lengthen your arm strokes and work on your catch.
So now you can have fins that give you extra speed and the correct kick timing!
Leg fins imprint the correct kicks on your muscle memory, the more you swim with them. You position the fins on your legs to face your kick direction and match your kick. This works for freestyle, backstroke and fly.
Regular foot fins work with a very different kick to your natural kick. You can feel the difference. For example, they cause you to slope your thighs down, bend your knees too much and strain your calf muscles too much. Foot flippers imprint the wrong muscle memory for your legs and arms, as well as for your stomach and torso muscles too. This incorrect muscle memory imprint happens because the different foot flipper kick style also changes your arm pulls and your entire body balance. So alternating between foot flippers and barefoot swimming confuses your muscle memory.
So regular foot fins imprint their own, different kick on your muscle memory. You feel this when you take them off and swim without them. It often takes a number of laps to reduce the muscle memory of their different kick, to get back to your natural good kick. Many competitive swimmers know this. So you can see for yourself why foot flippers do not improve your natural swimming kick. They may even be making it worse.
Leg fins overcome these problems because they attach to your legs. You position them to match your natural kick direction and kick action. This lets them match your natural kicks. So they imprint natural, correct kicks on your muscle memory. So they guide and strengthen your natural kick technique, speed and endurance. You notice ongoing improvements each time you swim. A useful trick is to swim a bit more just after you take them off. This helps to imprint correct kicks on your muscle memory that stay with you in the long term .
Now you can have fins that give you extra speed and imprint correct kicks on your muscle memory!
The FAQ listed above are only about the hip power benefits of leg fins. For all FAQ please see the FAQ summary.