I am a casual swimmer who does a steady breaststroke in the pool. I am often overtaken by people doing front crawl, but who is actually swimming the more efficient stroke?
@laurafae_,via Twitter
Advertisement
As a competitive swimmer for 10 years, front crawl is the most efficient stroke when done correctly due to having the least active drag. However, if the technique isn鈥檛 correct, it can be one of the hardest.
Chris Boynieson, via Facebook
In terms of energy expended, front crawl is more efficient for a skilled swimmer. Breaststroke uses the big leg muscles, and you can spend half the stroke in a glide, so it feels much easier.
@newnhamengineer, via Twitter
It is so difficult to get the breathing exactly right for the front crawl, which makes it more exhausting than breaststroke. While breaststroke is less efficient, it is more forgiving, manageable and practical.
@welsh_shaun, via Twitter
There is a reason 鈥渇reestyle鈥� competitors all do front crawl. Technically, they could choose any stroke for these races.
@TomorrowMaking, via Twitter
I write as someone who has been a competitive swimmer, a lifeguard and is now a leisure swimmer. If I wanted to reach someone quickly, the most efficient stroke is front crawl. If I want to swim indefinitely with no speed concern, then breaststroke is.
@the_biologian, via Twitter
Faster doesn鈥檛 equal more efficient. You can drive your car slower and get better miles per gallon. Going fast covers distance quickly, but will not get you as far per unit of energy expended.
Simon Dales, Oxford, UK
The front crawl is much more efficient than breaststroke.
Water is very dense, so swimmers are fighting drag all the time and must minimise the area of any body part in relation to the direction of movement. Ideally, you only move your limbs aft (rearwards) in the water, but with breaststroke, you have to push your arms and legs forwards and sideways, which creates a lot of drag. With freestyle, the arms mostly move backwards in the water, and are then moved forwards 鈥渇or free鈥� in the air.
Efficient swimmers spend most of their time long and flat in the water, like a telegraph pole.
In open-water races, swimmers tuck in behind each other to reduce drag. A breaststroker鈥檚 wake is too diffuse and turbulent to be of much use for this. Behind a freestyler, it is smooth and tight. The swimmers tuck tight to each other and synchronise their arms.
Mike Follows
Sutton Coldfield, West Midlands, UK
Front crawl allows you to travel further or faster, or both, using the same amount of energy.
Drag increases with the square of a swimmer鈥檚 speed. This favours a stroke with a more constant speed as a big penalty is paid for bursts of speed. The front crawl produces a more even speed, partly because the application of power is spread out over two arm pulls for every double-arm pull in the breaststroke.
In front crawl, maybe 90 per cent of the power comes from the arms and 10 per cent from the legs. For breaststroke (and butterfly), the arms and legs share the effort equally. Arms are better designed to pull the water.
The breaststroke allows swimmers to keep their heads above water at all times, but competitive swimmers will spend most of their time submerged, as they experience less drag.
If you look at a swimmer head-on, you will see that the best front crawlers spend most of their time with their shoulders and hips nearly perpendicular to the water surface. They achieve this by rolling their bodies through 180 degrees between each arm pull. This makes their 鈥渉ull鈥� narrower and means they come up against less drag. There seems to be less scope for breaststroke swimmers to reduce their drag.
But it might be consoling for breaststroke swimmers covering the same distance as a front crawl swimmer to know they will burn more calories during the session.
To answer this question 鈥� or ask a new one 鈥� email lastword@newscientist.com.
Questions should be scientific enquiries about everyday phenomena, and both questions and answers should be concise. We reserve the right to edit items for clarity and style. Please include a postal address, daytime telephone number and email address.
91色情片 retains total editorial control over the published content and reserves all rights to reuse question and answer material that has been submitted by readers in any medium or in any format.