Noa Markou just asked us a great question on Instagram:
I read your article (www.feelforthewater.com/2012/08/bent-it-like-becky.html) and would greatly value your opinion on the following. It states that an elbow bend of around 110° offers the most propulsion. If that is the case, why do sprinters who need maximum propulsion catch with straight arms? Thank you for any feedback...
That's a great question thanks Noa! Let's unpack:
Firstly, you are right to say that we recommend a bend at the elbow of between 100 and 120° to give you the most effective propulsion. Here's double Olympic Gold Medallist Rebecca Adlington demonstrating this position, very much in the sweet-spot with an elbow bend of 110°:
Becky is a distance swimmer specialising in longer distance events such as 800m.
As you point out though, often sprinters focusing on short races such as 50 and 100m pull through with a slightly straighter arm than that (although not completely straight as your question suggests). Here's Mr Smooth himself Jono Van Hazel showing that slightly deeper "sprinter" pull through:
Why does he do that and what's right for your own swimming?
One reason sprinters such as Jono pull through with a straighter arm is so that they can produce high levels of propulsion whilst moving extremely quickly through the water at 50 seconds per 100m pace or quicker. The straighter arm is like using a bigger gear on the bike, for a given movement at the shoulder the forearm and hand moves further and more quickly to keep up with the speed of the water moving past the swimmer.
Although this straighter pull technique can produce more propulsion that doesn't make it better. Inevitably it involves pressing down more on the water at the front of the stroke (see below) which wastes a lot of effort. It also dramatically increases the load on the shoulders meaning you have to be extremely strong in the shoulder muscle groups - so much so that even elite athletes struggle to sustain a deep powerful pull through for more than 100m of swimming.
But there's another related benefit of a deep pull to sprinters we should mention. To get quickly into this position involves moving the hand quickly downwards through the water from the front of the stroke:
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That press downwards creates lift, bringing the front of the swimmer higher in the water. Normally we say that's a bad thing because lifting you up at the front sinks you at the rear, creating lots of drag. But over short distances sprinters are able to combine this with an incredibly powerful leg kick which overcomes that downward pressure on the legs to the point where the rear also lifts high, bringing the whole body higher in the water.
That might sound awesome but don't deliberately introduce this to your own swimming unless you are a sprinter yourself. If you are typical adult swimmer - or high level distance swimmer - you simply won't be able to kick powerfully enough for long enough to use this technique. And you'll use an incredibly large amount of energy trying to do so.
So why do Swim Smooth recommend a slightly shallower pull through at 100 to 120° of elbow bend? The first reason is that biomechanically it takes the load off your shoulders so that you engage your chest, lats and other back muscles. These are some of the largest muscle groups in the body such that they can sustain the effort over a longer period of time.
Secondly, bending the elbow earlier in the stroke means a much smaller press downwards on the water, meaning less lift at the front and so less sinking of the legs at the rear. The result - much lower drag.
Bear in mind that this is still a very powerful way to pull through the water, the best distance swimmers can sustain 55 to 60 seconds per 100m pace over long distances using this technique and moderate kick power. That's the sort of speed most of us can only dream of!
So to answer Noa's question in a nutshell, although a deeper pull can give more propulsion over 50 to 100m, by using a little more elbow bend you will be able to produce plenty of propulsion over long distances.