Recently, I had a Video Analysis session with a swimmer from Canada whom recently moved to Kuala Lumpur. The main issue in her swim was, 'I feel I had to double effort to swim the same speed as my husband'. Why so?
KICKING TOO HARD
Kicking too hard burns a lot of your oxygen intake. This is the main reason why swimmers feel breathless other than poor breath control factor. The reason why your body naturally kick too hard is because you have poor catch and pull at the front. If you just slipping or catch the water with a very straight arm, you are sending yourself upward and not forward! Sending yourself upward means you are not creating propulsion ahead thus lifting your upper body high in the water and dragging legs low in the water. When your legs is low, the body subconsciously reacts to it by increasing the intensity of the leg kick and this is the moment when your oxygen consumption is at high peak.
How to spot if you channel too much oxygen to the legs?
Take 100M swim without buoy and then another 100M with pull buoy in between of your thighs. You may time yourself to see the difference in time.
1) If you find swimming with pull buoy slows you down, you can be assured that your swim speed is mostly derived from the leg kick.
2) If you find the amount of exhaustion has drop significantly when using pull buoy, that shows that too much of oxygen has been used when you swimming with leg kick.
How to tone down the leg kick?
Slowing down the leg kick wouldn't solve this issue and you will find out that your swim speed drops significantly. Working on the catch mechanics such as 'catch setup' and 'high elbow catch' at the front is the best advise for any swimmer who faces this issue. By working on catch mechanics at the front, you will less dependent on the leg kick to propel you forward as the propulsion now initiate by the front end and your strong leg kick will tone down naturally.