THE SCIENCE OF SPEED PART 1 - WATER

GETTING FASTER IS THE DREAM FOR MOST ATHLETES - BUT WHEN IT COMES TO SWIMMING, WHAT ARE THE FACTORS WORKING FOR AND AGAINST US? FROM HYDRODYNAMICS TO MARGINAL GAINS, WE EXPLORE HOW TO GENERATE SPEED IN WATER

- HELEN WEBSTER 

Water seems to exist beyond the sphere of logical science sometimes. You know the days - the ones where you get into the pool or lake and it feels like someone has tipped treacle in. Every stroke is an effort, you're fatigued after a few hundred metres and would swear someone has attached bricks to your feet.

Then there are the good days - the days you feel more dolphin than human, slipping though the water with ease, wondering why it can't be like this all the time. Obviously the water is the same though (provided you're in the same conditions) so why does it feel so much harder some days - and what can actually help to make us faster?

DENSITY AND DRAG

First, it’s worth briefly considering the properties of water. Without going too into GCSE chemistry, water is the only abundant substance on earth to exist as a gas, liquid and solid and each molecule is made up of one water and two hydrogen atoms. Water’s density is 1 gram per cubic centimetre, which is around 800 times that of air, and the hydrogen bonds also create surface tension (which is why light insects can sit on the surface). So if you’ve ever thought swimming is much harder than cycling or running – you’d be right – and this helps explain why swimming is so much harder on days you’re tired or a bit under par.

So what does this mean for us as swimmers? Here to simplify things is Paul Newsome, head coach and founder of swim coaching platform Swim Smooth. “We know that water is 800 times more dense than air. So consequently the resistance that you encounter when you’re swimming is much, much greater. That creates drag which slows us down – so basically when we try to swim, we are looking to minimise drag and increase effective propulsion. For most new swimmers, reducing drag is the key thing.”