Swim Tech Video: eliminate sinking legs

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This is another cracking swim technique video from Dan Bullock, Head Coach at Swim For Tri.

Like many great things, simplicity is what does it for me. At just a minute long, it simplifies what can at times feel like a mystery – why do my legs ‘sink’ when swimming when my training partners seem to have no such issues?!

Watch, learn… and then put this great advice into practice. As a self-confessed pull buoy addict, I almost feel as though this has been written for me personally…


It is imperative to change your approach to swim technique in order to break through to more economical swimming. Working from the legs up may seem strange, but they do cause most issues. Improving your leg kick is possibly the biggest breakthrough you can make to your front crawl stroke. A perfect leg kick with a less-than-perfect front crawl arm pull is better than a bad kick and a perfect pull/catch position. A wetsuit will not cure a bad leg kick, and continually pulling will not help solve the issues that are slowing your full stroke front crawl. Adding fins will generally make a bad leg kick faster, but it will not stop it from tiring you out. Wearing a band will reduce a bad kick but not teach you what a good leg kick is.

The kick should not be engaged to the point that it is overly propulsive. We need the kick to hold the body in position, to help initiate rotation. It is not about propulsion. It is absolutely necessary to have an efficient front crawl leg kick to swim faster. The bike and run are still to come once the swim is complete, but a good front crawl leg kick will not overtire your leg muscles.

What we want to avoid is the kick being too big – that is, kicking outside the profile of the body and creating drag. The disparity between how you imagine you kick and what actually happens can be huge. Frequently when people see their video playback they are amazed to see the width and depth of their kick compared to just how small a good kick is: they cannot believe ‘that’s all it is!’ It is easy to see how this happens: on dry land strong leg movements do create speed, and the bigger and faster movements usually dictate big, fast returns. The skill when it comes to swimming is limiting the range of movement. The leg kick even while mechanically accurate in terms of a relatively straight movement from the hip can still be quite big.

Using the ‘plank’ position as well as the Pilates ‘swimmer’ movement will supplement and accelerate an accurate small kick. If the leg kick is likened to the movement of a pendulum, then it is easy to see how a small movement at the hip can generate such large unwanted positions down at the feet. Core exercises will add rhythm to create a good small kick, and the core strength to control it and keep it small. It is also necessary to have flexible ankle mobility so that the feet can turn inwards and improve ‘usable surface area’. Feel the big toes tapping as a constant reminder of this aspect of the kick. This will also stop the feet splaying too far apart if you maintain a fast rhythm.

If all the above fall into place and your kick mechanics improve, then the kick will add traction to the stroke (rather than propulsion). You will then stand a better chance of creating rotation around the long axis internally.