Fingers apart or fingers together – which makes for more swim propulsion?


Just before I set off to the pool this morning, I took my rings off. My husband asked what was I doing? I said I can’t get my fingers together to swim with all the rings on. He asked me why I would want to, because all the Pro’s on the television don’t, they spread their fingers.

He had a point. So the whole time I was swimming up and down I wondered which was better, fingers together or fingers apart. I set about finding out the answer to the question!  

I had always assumed your hand acted like a paddle, therefore fingers together must have been better. I was amazed with the results that I discovered.

You may well be aware of swim smooth? Well their forum was the top of the search list when I asked google my question.

THE VERDICTS:

1.      Fingers together may create tension in your arm – tension is not good, and will prevent you performing at your best.

Maybe so, but I need science!

2.      Slightly relaxed gently spaced seems to be the preferred consensus.

This seems to produce a greater surface area, therefore creating greater propulsion and there is very strong research to back this up too. Here’s the evidence:

 ‘It was determined with 95% confidence that a finger spread of 10°creates more stroke force than a fingers-together configuration across all pitch angles tested.’

Here we show, through computational fluid dynamics(CFD of a 3D model of the hand, that an optimal finger spacing (121,roughly corresponding to the resting hand posture) increases the drag coefficient (+8.8%), which is ‘functionally equivalent’ to a greater hand palm area, thus alowerstrokefrequencycanproducethesamethrust,withbenefitstomuscle,hydraulicand propulsive efficiencies

I am a picture person, and this picture was what made it clear for me.

‘Large vortices develop at the closest finger spacing, resulting in a strong back flow increasing the pressure on the dorsal surface of the hand, thus decreasing the pressure differential on the hand and the overall pressure drag. At the optimal spacing, water jets produced between the fingers prevent the formation of the vortex and contribute, via a reduced backflow toward the dorsal side of the hand, to create a stagnation region with the consequent increase in the drag force.’

Therefore, they conclude that the mid spaced fingers are the best, back vortices are created with closed fingers, and too much water escapes between wide spaced fingers.

Who’d have thought eh?!

I think I might have to try the slightly spaced fingers approach and see what happens!!

THE EXPERIMENT:

I decided to try this out in a swim session. This week is recovery week, and the set i was due to do was a 45 min steady swim, no stopping. I decided to experiment with finger position, and see what happened. I wear a lap counter, and am usually quite good at steady constant pace. I have done this set regularly during recovery week, so i know how many lengths i usually get into 45 mins.

I took a random sample of lengths, every occasionally, when i felt like it. I did some fingers together, some fingers spread, and some with hands gently relaxed. Then i worked out the average of the lap results.

Fingers together felt harder. I imagined that therefore it was faster. In fact it wasnt. At first it was no different. When i got the hang of the correct finger sprtead, fingers together was in fact slower, by a fraction.

Fingers spread apart: I definately felt the water slip between my fingers and this method was definately slower, by 1 second or more, on average (per 25m lap)

fingers gently relaxed, small gap: Eventually i concluded that this simply means relaxed hand, fingers slightly apart. This was definately the best method. It felt like a lot less effort to pull the hand through the water, and overall, it was at worst, no slower, and usually, faster, by a second at least.

Overall, I still covered the same distance that i usually do, however it definitely felt like a lot less effort, and i imagine, once i get the hang of it and do it consistently i will be able to cover more distance in that same amount of time.

Very interesting!

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