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- Welcome back to the Triathlon Training Explained show,
powered by TrainingPeaks, now if from time
to time you are riding indoors, perhaps
on a Turbo Trainer as I am today,
then you will have quite likely
at some point complained that it feels somewhat hard,
or maybe considerably harder than when you ride outdoors.
Your heart rate's higher, your power's lower,
your FTP maybe feels a bit out
of reach, what is going on, well you'll be pleased
to know that you are definitely not alone.
Today, I'm gonna be exploring that conundrum and be looking
at how it happens and what you can do about it.
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Now, I must admit there have been times that I've jumped
on the indoor trainer and I've wondered,
what the heck is going in with my legs?
And it can really play with your head
because effort just seems so much harder to achieve.
Sometimes, impossible whereas normally you're knocking 'em
out of the park when you're outside on the road.
So, what do we think is happening?
Well, I've been out and I've asked you just that.
Now, why is it harder, indoor training?
- Because you don't get any rest.
You have to keep going all the time.
You're not able to glide and you
have to keep it in the zone or rate area
which is much more difficult when you're on the bike.
- The thing I find hard about indoor training
is that there's no distractions,
there's no changing gears, there's no steering,
there's no needing to be aware of traffic.
So, you really have to focus on
the pain, and how much it hurts.
- I think it's because of the heat
and you don't have the wind coming against
you cooling you down, so you can easily
overheat which can make you feel
like you are putting in much more
effort than you actually are.
- It's a definite love/hate relationship
with the indoor trainer, and it
makes training a lot harder.
There's no free wheeling, coasting,
sitting behind people, there's constant
tension on the chain as you're pushing
through the session.
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- Well, there are some very good theories there,
but let's see what the science says.
Now, one theory is that it's due
to a reduced cooling effect.
See, the human body has quite
a small and finite range it can
efficiently operate in, and that's
between 36.5 and 37.5 degrees Celsius,
and this is what's considered
our normal body temperature.
Now, if we go just a fraction above that
we can start to feel a little bit off
and actually, our training like
cycling might start to feel a
bit more laboured.
If we just go about three degrees
Celsius above maybe to around
40 degrees Celsius
we can really start to feel quite bad,
and actually we can start to
experience the onset of hyperthermia.
Now, obviously when we're cycling indoors
we are stationary, but our bodies
are still creating vast amounts
of this energy to power our legs
and keep things working.
So, this is where things get really interesting
because the cells that are in our body
actually get their energy from food
and then creating and using that
through ATP molecules, and they
are then used to make our body work
and make our legs work, and we have to cycle.
Through this whole conversion,
it's actually only an overall efficiency
of around 25% that's actually used
to make our legs work.
The other 75% is, wait for it,
is lost through heat.
So, if you take a cyclist cruising along
outside at about 30 k.p.h.
Their experience, a nice wind, a nice breeze,
a bit of headwind.
That's equivalent of a big big ol' fan
around 30 k.p.h or perhaps even more
depending on the conditions.
When we're riding inside, that headwind
that breeze, it's all gone.
So, you can start to understand
how the body starts to feel
the effects of this heat, and it
starts to respond in a few ways.
Firstly, we have a slight increase in our heart rate.
Secondly, the blood starts to
shunt, and move away from our muscles
in an attempt to dissipate the heat.
So, it goes towards our skin to try to relieve
that heat out of our body,
but through doing so it's obviously
taking oxygen away from our muscles
which then might start to experience
a slight loss in power.
Another way it tries to dissipate the heat
is through sweat, and in doing so
we can end up feeling slightly more dehydrated
and again, a loss in performance.
Also, as temperatures really rise
then our head and our brain literally
cook, meaning it leads to a decrease
in motivation, concentration,
and perhaps even lowering our pain threshold.
But, of course we all know that,
that's why we use a fan.
A fan is there to essentially
recreate the wind to try to keep
us cool, to wick the sweat away
from our skin, and stop us from overheating.
What I would say, is that I know
from experience that I am pretty
much always dripping with sweat
when I get off an indoor training session,
despite having a fan.
So, perhaps it does contribute
in some way to making indoor training harder.
Now, another theory is that it's
due to being in a fixed position.
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So, without the ability to actually
move the bike, we're causing ourselves
to use more isolated muscles,
that perhaps aren't used to working quite so hard.
When we ride outside on the road,
we're able to shift our body weight around,
get a powerful bike, move the bike around.
In turn, we can start using more muscle groups,
even our upper body, our core,
as well as obviously our legs
to really help produce as much power
as possible, and actually, through
doing that we can allow some muscles
to recover and rest, whilst others
are working to overall help to
produce as much power as possible.
Another thing athletes do complain about
is that some muscles, or certain areas
of muscles might hurt.
Such as, adductors coming up the inside of the leg.
That's a real classic one because
when we're riding outdoors we
don't tend to utilise and use
those muscles quite so much.
They seem to get quite a hammering
when we're riding indoors and that
can really contribute to a slight loss in power.
What I would say is that, with
time when you're riding indoors,
you will start to train those
muscles up, condition them,
get better at using them,
and hopefully start to find
it's less slightly of an effort.
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The indoor trainer also has the
ability to suck the life out of
even the most motivated of athletes.
So, if you're riding indoors,
maybe in your garage, your dark garage
next to your lawn mower, and a bunch of tools;
Let's be honest, that is nowhere
near as motivating as riding outside
on the road, on a clear sunny day.
So, if you're not as motivated
that is going to contribute
to a loss in power.
So, what I would say is for indoor training
try to tailor your sessions specifically
for indoor training, keep them engaging
keep them interesting, keep that body guessing.
Try to make them slightly shorter, more intense.
Maybe don't do quite so many of
the longer rides indoors, otherwise
you are just going to mentally burn yourself out.
On that note, also things like Zwift, and other
virtual indoor training platforms are great
for keeping you interested, and engaged
in indoor training.
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But, the big reason I believe
comes from the indoor trainer itself,
or at least from some indoor trainers.
See, when you're cycling outside on the road
and you stop peddling, you coast,
you just keep on going,
But when you're inside on an indoor
trainer, and you stop cycling,
you pretty much come to a
stop within seconds, or at least,
on some indoor trainers.
So, what's happening is when you're outside
you have the momentum from your
own body weight, your bike weight,
and that just keeps you going
so you can free wheel, and you
can come off the gas and coast.
Whereas, inside on an indoor trainer,
you have a flywheel that's attached
to the resistance unit, and what
that flywheel tries to do is,
it tries to replicate that feeling
of riding outside on the road.
But, from experience, and we all know this,
It doesn't really do it that well.
So, what you're having to do is
work harder to try and maintain that momentum.
Because of this flywheel, it also
changes the way that we apply force
throughout the peddle strikes.
So, when we're cycling outside on the road
you may think that you're applying force
evenly and smoothly throughout
the whole peddle strike, but in actual fact
what you're probably doing is
applying force through the down stroke,
and that is also aiding the recovery
of the other leg back up to the top
of the stroke, and vice versa.
This all changes slightly when we start
to go up a hill, because we need
to apply force throughout the whole
peddle strike to maintain that momentum,
otherwise we'll either fall off our bike
or fall back down the hill, and that
is very similar to when we are riding
on an indoor trainer due to that
flywheel, and that inertia that we've
got to overcome on the flywheel,
and try to maintain that momentum.
Now, all of these factors are contributing
to what is making it harder,
and considerably harder than when we'd
ride out on the road where we've got
minimal resistance from tyres
and from wind for instance.
But, fortunately these issues are
becoming less and less, due to
advances in the flywheels.
We've got bigger flywheels on the dumb trainers
but most importantly, it's due to
these smart trainers, and direct drive trainers
as I'm using today.
So, by taking the rear wheel out
of the equation, and now including
this larger heavier flywheel,
a simulated rear wheel momentum is created.
When you stop now, on a direct drive trainer
the flywheel continues to roll
until that inertia is exhausted,
and all of that contributes to
a much more realistic feel.
Whereas before you would feel that resistance
on the bottom and the top of the peddle strike,
that is all gone, and all that helps
to allow you to produce very similar power
on the indoor trainer as you would outdoors.
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Now, regardless of the type of trainer
that you're using, add all those factors together
and you can start to understand
why some people find riding indoors
that bit harder.
Which brings us on to the big question,
should you be adjusting your
functional threshold power, or FTP
for riding indoors, and that is
a very good question.
What I would say is if you are consistently
riding at around 10 watts below your
usual power compared to when you are
riding outdoors, then yes.
But before you do that, just check
on the accuracy of your power metres.
Some people when they ride outdoors
on the road, they use the power metre
that is on their bike and when
they are indoors they read
the power from their smart metre,
but they might be reading slightly differently.
So, just check on that, and also
obviously, do calibrate your power metres
from time to time, to really
improve the accuracy.
But, back to the big question,
and if you are heading indoors,
maybe for considerable time for the winter,
then definitely do an FTP test indoors
to make sure you are tailoring your zones
around that FTP, so you're not
working too hard when you're indoors,
or perhaps even too easy, and
on the subject of riding too easy
you do need to make sure that
you are retesting quite regularly
with an FTP test.
I would normally suggest every six weeks,
but if you do find that you move on
quite considerably, then obviously retest sooner.
With all that being said,
if you train exclusively indoors,
and you're keeping yourself nice and cool,
and you're highly, highly motivated,
then you may well not actually see
any difference, or very little difference
between your power indoors vs. outdoors.
Some people just don't find they have
a difference, but they are certainly
the lucky ones, but hopefully
what we have shown today, is that
it's not all in your head.
It can actually be harder training indoors,
and actually with these advances in the
direct drive smart trainers, hopefully
we'll see less of these complaints with time.
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Now, if you'd like to see a
'How to choose an indoor trainer' video
just click up here, and if you'd
like to see our other indoor vs. outdoor
video, but this time for running
just click down there.