- Emma and I looked up why most riders can produce more
power on climbs or on the flat, but how the same rider
can rarely produce the same power for the same effort
on both terrains.
- Yeah.
One explanation was that the greater inertia that
comes from riding at faster velocities, i.e. on the flat,
changes the way you transfer power from
your legs to the pedals.
Now the other theory suggests that the gradient of
the road itself changes your relationship with the bike,
specifically the position of your hips
in comparison to the bottom bracket.
- Two theories, then.
But can we test it?
(upbeat music)
- It's not gonna be the glasses that do it actually.
But this, this being the Leomo Type-R.
Now, they got in touch with us to ask, to see if we wanted
to use this little gadget to do some science.
Now as you know, we need all the help we can get,
so the answer was a resounding yes.
Thank you very much.
Now, what this is is firstly, five little wireless
sensors that attach to various parts of your body,
and then give you motion tracking data in real time.
Firstly displayed on this head unit, but then of course,
also saved for further analysis later on.
- So, it's kind of like a supercharged version of
something you might find in a really advanced bike fit,
but you can use it at home, and take it outside
into the real world in all sorts of conditions.
- Yeah.
So, you could use it if you need to analyze your position,
maybe check out your time trial bike position,
all sorts of stuff, really.
But in this case, it's gonna allow us to keep
a very close eye on our body position, our technique,
whilst riding at VO2 max, so full gas,
both on the flat and on climbs,
outdoors, in the real world, but firstly simulated indoors.
- Does this mean we're gonna get some really cool graphs?
- Lots of graphs.
- Yes, everyone loves graphs.
- But it is gonna hurt first.
- Ahh.
- So firstly, what's the protocol?
How do we use this to analyze how we produce power
on the climbs or on the flat?
We will start with a warmup, and then ride at 420 watts
on the flat for five minutes, ease off, and then ride
420 watts again for five minutes on a climb.
Outdoors, it's very simple.
We will find a flat road and we will find a climb.
Indoors, how do you simulate gradient?
Well, fortunately, it just got a whole lot easier
'cause Wahoo has very kindly sent us one of their new
KICKR CLIMBs, which does exactly that,
right up to gradients of 20%.
As you can see, it angles the bike,
but it also changes the resistance at our smart trainer
at the back, in this case it's a Wahoo KICKR.
Now, it could do far more immersive and exciting things
like respond automatically to what's going on
in Zwift, or respond to a route that we've
downloaded onto our head unit.
But in this case, we literally need it to angle the bike
and then increase the resistance at the back.
And that increased resistance is gonna effect the inertia
because we'll be using much, much harder gears
when we're riding on the flat,
so, that's gonna get that really weighty flywheel
turning faster to generate that inertia.
(upbeat music)
As you can see, Chris has drawn the short straw,
and so is doing his VO2 max intervals first.
Why don't you warm up, mate?
Let's do a quick introduction to Mio, shall we?
So, Mio is a sports scientist, who works at Leomo,
and very kindly came in to help us out.
Basically, you do cool experiments for a living, right?
So, in this case, the five sensors that we've got on Chris,
can you talk us through what each one is gonna tell us?
So, maybe starting with the sacrum one?
- Yep.
So, Chris is wearing the sacrum sensor which measures
his sacrum angle as well as it tracks the motion,
the left, right, rocking motion on the saddle,
and it also outputs the rotation motion
on the saddle as well.
The rotation is about his central axis.
And then he has two thigh sensors, the left and the right,
which measures the range of motion, minimum and maximum,
of how far the thighs travel up and down.
And then he has left and right foot sensors,
which it's tracking the movement in the sagittal plane
of the foot itself.
So, how much heel's dropping, his foot drop.
- Okay, and so, as an overall picture then.
Do you think that we might tell a difference as the bike
is inclined, and then also the resistance
on the flywheel changes?
- Yeah, so the incline difference whether he's
doing the flat or a simulated climbing,
that may show up on his pelvic rocking
and pelvic rotation.
I've seen that case before.
And with the resistance on the flywheel,
if the inertia is significantly different,
then that might translate to Chris pedaling
slightly different.
And that would show up as a motion indicator
on his foot sensors.
- Okay, so fingers crossed then.
If there is a difference between climbing and
riding on the flat, then the foot sensors
should pick up different pedaling technique,
and then the sensor on his sacrum could well show up,
again in different pedaling technique, but from the top
as opposed to the bottom.
All right.
Okay mate, you probably better find that 420 watts
and give it some beans.
(upbeat music)
All right, Chris, are you ready, mate?
- I am as ready as I'm ever gonna be.
- Five minutes at 120% of FTP.
- Yeah, which I recently found out means 350 in Dawson.
- Is that all?
- Yeah, so.
- Okay, mate, all right.
Right, I'm gonna press the select button on here,
and then I'm gonna go on my phone as well.
You ready?
- I'm ready.
- Okay, three, two, one, go for it, mate.
(upbeat music)
What a legend, come on mate.
Good effort dude, good effort.
Ready, there he goes.
(upbeat music)
Right then, Chris, you should recover by now.
I have.
- I'm getting there.
- Okay, good stuff.
Right, I'm gonna increase the tilt then.
So, one, two.
- Going up.
- Three, four, five, six, seven.
- Oh, I'm slowing down.
I'm changing gear.
- There we go, right.
So, 8% gradient simulated.
(bike chain clicks)
You ready?
- I feel heavier than I did a minute ago.
- Good stuff, mate.
Okay.
Read me the lap.
- Yep.
- Okay, three, two, one, go.
(upbeat music)
- That was nowhere near as comfortable as the first one.
It just felt like an uphill struggle, literally.
(heavy breathing)
- Well done, mate.
That was two cracking efforts there.
And the best thing is, that's all the data
we need apparently, before now going outside.
- Not quite.
It's sorta my data.
Your bike's in the next room.
So, go and get your shorts on.
(upbeat music)
- All right, then Chris, let's do this.
Lower percent, five minutes.
What was yours, 420?
- 431 actually, Si, in the end.
- All right.
Ready.
Okie doke.
(upbeat music)
(heavy breathing)
- Three, two, one, stop.
Good work, Si.
That looked enjoyable.
(heavy breathing)
- Love it.
(laughing)
(upbeat music)
- So, now that Si's done his five minutes on the flat,
he's convinced he can do a little bit more
whilst going uphill at 8%.
So, we're gonna crank it up.
- All right.
- Get ready for another five minutes at 120% of FTP.
- Okay, one, two, three, four, five.
- The suspense.
- Six, seven.
- Three, two, one, go.
(upbeat music)
Three, two, one, good work, Si.
All right, well that's test number two done.
Si's gonna spin and catch his breath, and then we're gonna
go over to the other side of the room
and check out the results.
(upbeat music)
- Well Chris, we have a lot of data to go through, don't we?
Two sets, of course, yours and mine,
and for both indoors and outdoors as well.
- Yeah, and a few things jumped at us straightaway.
Particularly Mio, who could barely contain herself
with the excitement when she saw Si's frankly, well,
unorthodox pedaling.
- Yeah, it turns out, that my pedaling technique is bizarre,
very asymmetric, not in terms of power output,
which left and right balance was still 50/50.
But it basically seems that my left leg and my right leg
do completely different things.
So, actually we've got three data sets, haven't we?
We've got Chris', and then we've got my left side,
and my right side.
- Yeah, and not only Si's left and right legs were doing
different things, Si and I also
differed quite significantly.
- Yeah, so after all of that, can we actually answer
our initial question?
Does power output vary because of inertia or gradient?
- Well Si, we've got to look closely.
- We do.
Firstly, at foot angular range.
So, how much you move your ankles.
Now, for both Chris and I, there was a measurable difference
in this, specifically, when you look at us climbing,
there was less range of motion in
our ankles compared to the flat.
So, it suggests, at the most basic level,
that there is some kind of difference in how
we're transferring power to the pedals
between flat and climbing.
- Well, that is a fairly basic observation.
- Thanks.
- And to which Mio suggests we look even closer
to the data at the individual pedal strokes.
And at that level, you can see that there is a difference
in the initiating of the push down phase
of the pedal stroke.
- That's right.
So, when climbing, you can see that that power transfer
phase starts to happen at about the one o'clock position.
However, on flat riding, you'll see that that
power transfer phase happens even earlier,
even before potentially the 12 o'clock position.
- There's also a difference in the distribution
of the dead spot score, which hits at a different leg
movement throughout the pedaling cycle.
The greater disturbances, in this case, were happening
around and after the bottom of the pedal stroke.
- Yeah, with thigh movement, which you can pick up
on these graphs, there's little wavy motions
on the orange and the yellow lines.
Now, those were consistent between indoors and outdoors,
but there were a few very interesting discrepancies
between riding indoors and outdoors.
Away from our original question, if you permit us,
a slight tangent just for a minute.
- Pelvic rotation actually decreased when outside,
primarily because the bike was no longer mounted
to a rigid, well, turbo trainer.
However, pelvic rock, so the fore and aft movement,
that did actually increase.
- Yeah, there we go.
The first one, you can kind of understand because
as you say the bike's not being held underneath you,
but the second one, that's just kind of weird.
Anyway, back to our original question, although
sticking with pelvises just for one moment.
One thing that was consistent between indoors and outdoors,
but that varied between flat and climbing was
the pelvic angle.
So, when riding on the flat, there was a lower pelvic
angle, i.e. your pelvis was closer to horizontal
than when climbing.
Now, you would think, wouldn't you, that if you angle
the bike, then the pelvic angle also increases.
But remember, an 8% gradient actually only equates
to an angle of about four degrees, which was admittedly
the exact same difference in myself, but less than
the seven degrees that we measured on Chris.
Although potentially, that's just due to you trying
to get more arrow on the flat and therefore
having a rotating pelvis compared to a
different climbing position.
- Yeah, that would make good sense because naturally,
when you're going fast on the flat, you do try
and tuck out of the wind a bit.
- Yeah, and naturally on an indoor trainer,
when going fast, you still get arrow.
- Yeah.
So, what does it all mean?
Well, we can see that as the gradient increases,
the way we ride a bike changes.
But gradient alone is not the reason because we know
the gradient increase was only equatable to four degrees.
- That's right.
And one of the most significant differences,
the power delivery initiation, was between
one o'clock and 12 o'clock, and that of course,
equates to 30 degrees.
When you combine that with the change in the dead spot
scores, it suggests, to us at least, you'll hopefully
let us know in the comments section what you think,
that the changes were not due to gradient,
but something else.
- Something else, something like inertia?
- Something like inertia.
Chris, I think we just did science.
(high five)
- Yes.
- Boom.
Yes.
- Feels good doing science, Si.
- Yeah.
We should do more science.
- Do I get a badge for doing science?
- You can wear the glasses, right.
- Oh.
- We would just like to say, genuinely big thank you
to Leomo for their help for this.
Hopefully, we'll be able to use this to do
some more science in the near future.
Now, if you would like to see that video
where we mentioned earlier about Chris and Emma
going through the existing studies
and the existing literature into this,
then please make sure you check that one out.
- And give us a big thumbs up before you do.