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What Is The Most Efficient Pedalling Style? We Test Flat Vs. Clipless Pedals | GCN Does Science


Last year, we shot a video: ‘How To Pedal
Like A Pro’, using our combined 40+ years of experience of both riding and racing, plus
the common wisdom that you should pedal in circles, i.e. dragging your heel through the
bottom of the stroke and pulling up etc. But a lot of people responded in the comments
section that this isn’t in fact the most efficient way of pedalling. It is true, there is a wealth
of scientific evidence to say that a full pedal stroke isn’t necessarily the most efficient.
But I don’t necessarily agree with some of these lab tests, and mainly because my perception
is that I do in fact add force to the pedal stroke somewhere other than just the downstroke. So we thought “how can we test this out the
GCN way?” Thankfully one of the top sports science centres in the country, here at the University of
Bath, have allowed us to do an experiment. First things first – we do realise that this
is not a completely legitimate scientific experiment. After all, Simon is the only person
doing this and according to what he just said, he’s only going to do it once. What we do
hope it will prove is once and for all whether as Si thinks he is more efficient by pedalling
around in circles using clipless pedals vs. just pushing down. Either way, at least we
get to put him through some pain. The hypothesis is that pedalling around in circles is more
efficient than simply pushing down and to test this, he’s in a very controlled environment.
He’s already doing the first of two ten minute tests. At the moment he’s on a 6% incline
here on the treadmill riding at 20km/h and if I just look at the data, that requires
around 300 watts and his heart rate at the moment is about 168 just over a minute through
this first test. Once we get to the end of the ten minutes we’re going to analyse various
things. The lactate in his blood, we’re also going to analyse some of the things in his
breath and also see heart rate etc as well. Then we’re going to repeat the test, but this
time we’re going to use just flat pedals to try and eliminate anything which will enable
him to pull through at the bottom of the stroke or even pull up, and then re-analyse all the same
metrics at the end of that to come to a conclusion. OK, Simon’s only got 15 seconds left to go
now. His heart rate is up to 175, so it’s gradually risen. Almost time to start collecting
some data through the breathing analysis and blood lactate. Now we’ve swapped the pedals over for some
standard flat ones with some normal mountain bike pedals which Si is riding on the treadmill
now. Exactly the same conditions – we’re on the same incline of 6% and the same speed
of 20km/h. Before we give you or even Si some of the numbers from the last test or during
this one, Si, how is it actually feeling at the moment from your point of view? Well it’s got to be said it feels bloody weird.
It does feel harder and it also feels much less smooth, I’m quite jerky on the treadmill
and that’s my perception, so I can’t wait to see the numbers. Right, well you’ve still got 6 minutes left
and so we thought that in that time we’d answer a burning question that we had from the last
time that we came here and used the treadmill. How is it that a treadmill, where you’re effectively
not moving anywhere, feels the same as when you’re going up a climb even though you’re
not gaining any potential energy? Well thankfully we’ve got Jonathan here from the University
of Bath, who’s going to explain. On the treadmill, we’re not actually gaining
any elevation, so why does it feel like we’re still climbing? I think what is a really good point is that
we use the treadmill so that it’s a really controlled environment, we can mimic and repeat
the speed and the gradient and there’s no changes in environmental conditions, so everything
is the same. Obviously the athlete is not moving forwards or backwards but they are
riding against the rolling belt of the treadmill and given the gradient as well, if they were
to stop pedalling they would come off the back. We know that they are expending energy
as they’re going through and also as we recorded the power, we can see what power they are
generating. Thanks very much. I think Si is close to ending
his effort now, so let’s go and see how he’s getting on. There’s now 20 seconds left for Simon, and
before we get all of the official numbers, I can say that I’ve seen a slight difference
here on my own Garmin. 10 seconds to go, Si. Also important to note that we did allow Si
adequate time between the first test and this one before he went on the treadmill again
to make sure that he was completely rested. 2 seconds, 1 second, and stop! OK Jonathan, let’s talk through some hard
numbers. Simon’s perceived exertion that he gave you at the end of the 10 minute test
– for the first one, the clipless pedals – it was 13. For the second one it was 15. The heart rate I was looking at, the average
over the last minute was 180 for the flat pedals and 175 for the clipless. In terms
of the blood lactate which you took out at the end of both tests – how did that come
out? Surprisingly it was actually the same – 3.1
millimoles for both rides so no difference at all seen there. So that was similar. In terms of the gas analysis
of the breath that you had, how did that come out? The VO2, which we recorded over the last 3
minutes actually came out at slightly different values, so 51 ml per kilo per minute for the
flat pedals and 53 ml per kilo per minute. Wow, so he was consuming more oxygen with
the clipless pedals than he was with the flat pedals? Yes. The clipped pedals were actually eliciting
a higher oxygen consumption. So perhaps the opposite to what we were expecting,
that’s interesting. OK let’s go and have a word with Si now that he’s recovered slightly
to see how he feels about those results. Simon, Jonathan’s just given us the results
and surprisingly the flat pedals appear in this single test to be slightly more efficient
than your clipless pedals, so what do you make of that? Yeah, I’m scratching my head a little bit
to be honest with you Dan. I am surprised, but I’ve been thinking about it a little bit
and the main feeling is that when I was pedalling with the flat pedals it felt like my shoe
was almost always about to come off the pedal. But then the fact that it was almost coming
off but not quite means that I suppose my natural pedalling style is one where I don’t
actually pull up, which I suppose I never really knew. But then, if it’s not adding
anything then presumably it should be as efficient, if not more efficient just using flat pedals.
But I’m not going to throw away my clipless pedals just yet because for a start I can’t
bunny hop without them! And also, this is a steady state ride. As you well know, even
in a race situation, the amount of times where you have to accelerate really hard, I know
full well that I do pull up when I’m generating the most peak power that I can and therefore
in a normal environment clipless pedals are still going to be the ones that win out. I guess that’s the thing, isn’t it? The laboratory
here does take all external factors out, but when you’re racing or training on the road,
you have all of those external factors. Anyway, stay tuned to GCN because we’re going to be
coming back here to the University of Bath to do more experiments with myself and Si
on this treadmill which should help to answer a lot of your burning questions.

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