More distance per Calorie: Walk vrs Granny Gear Uphill?



"Artemisia" <[email protected]> wrote in message
news:[email protected]...
> Peter Clinch wrote:
>
> > I recall one incident when a pal and I were taking our MTBs up a fairly
> > steep grassy field. I got bored at walking pace, and decided I'd walk.
> > While walking, I soon overtook my pal, still spinning happily in 1st...

>
>
> So isn't it actually more efficient energy use to walk uphill than to
> pedal, even if you do have unimaginably low gears and no topple-over on a
> trike?
>
> I'm thinking perhaps the only advantage of trying to pedal up my hills is
> the inconvenience of trying to stand up out of a recumbent...


You're on-road on your trike, which is a bit of a different place.

But more importantly with the trike you've got something you can't do on any
bike : stop and sit there. So you pedal until you're puffed, put the brakes
on (with locking device/velcro as appropriate) and sit there relaxing, coz
you can.

(And pushing a recumbent trike uphill is liable to be extremely tedious too)

cheers,
clive
 
Peter Clinch <[email protected]> wrote in
news:[email protected]:
>
> I think that's already been accepted and understood here.


Apparently not as Alan clearly said "We all know cycling is more
efficient in general, the question was whether
that's still true on steep uneven ground where walking may be quicker."

> The point
> is that when you throw rough ground into the equation there is a lot
> of inefficiency thrown in to the cycling because the bike and rider
> has to spend a lot of power moving up and down as well as along (why a
> full sus bike is faster downhill with the gravitational acceleration
> than a rigid, but it doesn't work so well when climbing at very low
> speed).
>
> The question is, is that up-and-down loss of efficiency bigger than
> the inherent inefficiency of walking. Since this was a grass field
> which isn't all that /rough/, I would suspect not in this case, but
> OTOH the grass gives a lot more friction to a constantly contacting
> bike wheel than a walker's feet which are typically above it for
> almost the whole time.
>
> I don't know. I suspect it's not the straightforward answer of a
> smooth
> road though (but on that smooth road again the messy Real World
> caveat
> that you can only burn energy at /any/ efficiency if the relevant
> muscles are still up to it, and if your cycling muscles are knackered
> and the walking ones aren't that could be a moot point).


But I doubt that rough grassy fields are relevant to Artemesia's original
question. Yes there are lots of ways you can make the bike less
efficient - throw in steps or a scree slope for example - but generally
none relevant to the originally posed question.

As for tired muscles, the evidence is that the efficiency does not
change, the muscles just get limited in the energy throughput, consuming
less energy and putting out less energy.

--
Tony

" I would never die for my beliefs because I might be wrong."
Bertrand Russell
 
On Sep 6, 7:09 pm, Artemisia <[email protected]> wrote:
> Peter Clinch wrote:
>
> > I recall one incident when a pal and I were taking our MTBs up a fairly
> > steep grassy field. I got bored at walking pace, and decided I'd walk.
> > While walking, I soon overtook my pal, still spinning happily in 1st...

>
> So isn't it actually more efficient energy use to walk uphill than to
> pedal, even if you do have unimaginably low gears and no topple-over on
> a trike?
>
> I'm thinking perhaps the only advantage of trying to pedal up my hills
> is the inconvenience of trying to stand up out of a recumbent...
>
> EFR
> Ile de France


Cycling (particularly on a recumbent!) is not a weight bearing
exercise like walking. That is to say, cycling up a hill requires you
to only move your center of mass up the slope, not carry it. When you
carry something up a hill you need to not only move it up the slope,
you need to support it's weight the whole time too. Think about
carrying rocks up a hill with a wheelbarrow vs a backpack. When
cycling the center of mass stays pretty still and thus follows the
slope of the hill without too much extra energy spent. Walking makes
the center of mass bob up and down a bit which uses energy that
cycling doesn't. Cycling has the added weight of the bike, and the
resistance of the drivetrain, rolling resistance, and wind resistance,
but in terms of calories per distance at slow speeds where wind and
rolling resistance are minimal, cycling will always be more efficient.
At high speeds where the exponential wind resistance is much greater,
one needs to expend a lot more energy to overcome this resistance, and
then walking is more efficient in terms of calories per distance. A
lot slower too!

Now in the case of a steep hill with grass and thus relatively high
rolling resistance, it may be that the increased rolling resistance
more than makes up for the difference of cycling not being a weight
bearing exercise. Gearing and what is a comfortable range of cadence
and force generation for the leg muscles comes into play too.

If you try pushing someone on a bike on a flat feild of grass you can
see how much resistance there is. And since it seems that riding up
this hill vs walking was more or less a wash despite the extra rolling
resistance, this suggests to me that cycling is that much easier than
walking by the same amount of effort it took to push the person on the
grass. (That made sense to me at least...)

Joseph
 
[email protected] wrote:

> I really find it hard to believe that an intelligent and experienced
> off-road cyclist could seriously dispute that in the situation as
> described, it may indeed be more energy efficient to walk.


I guess it could be the case that technically fewer joules came into
play, but we'd gone a long way up a big hill and our spinning muscles
were well spun. It was getting quite boring spinning them more, and
however /efficient/ they were at getting me up, they were tired.

But even if fewer joules came into play I wouldn't say it was relevant
to the simpler basic question of "was I better off walking or cycling at
the time?". Walking was the winner, it was subjectively easier, and
objectively quicker.

Biological and psychological factors of muscle tiredness trump "oh well,
it's just force times distance, you can't break the laws of physics you
know!" as far as /my/ body is concerned!

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email protected] http://www.dundee.ac.uk/~pjclinch/
 
"[email protected]" <[email protected]> wrote in
news:[email protected]:

>
> The first obvious omission is the weight of the bicycle (as you admit
> below) which is a significant penalty for the cyclist,


However if you are walking with the bicycle you still have to lift its
weight up the elevation so that drops out the equation. It only matters if
the choice is between walking up the hill without the bicycle vs cycling up
the hill with.

>
> I really find it hard to believe that an intelligent and experienced
> off-road cyclist could seriously dispute that in the situation as
> described, it may indeed be more energy efficient to walk.
>


According to measurements done by Schwalbe using SRM power cranks on a 500m
uphill grade a gravel surface increases the power needed by ~30% and a
grass meadow increased it by ~80%, depending on tyre width and pressure, so
still probably well inside the walking efficiency. [For safety adds
caveats of boggy ground, ground littered with big boulders etc etc]

I have already said that there are lots of caveats I omitted to my original
response to Artemesia's post starting this thread (<46e03452$0$7753
[email protected]>). Knowing Artemesia's cycling styles from her
posting history here I doubt very much that any of the scenarios being
posted to attack my original answer are of any relevance to her cycling.
YMMV


--
Tony

" I would never die for my beliefs because I might be wrong."
Bertrand Russell
 
Tony Raven wrote:
> Peter Clinch <[email protected]> wrote in
> news:[email protected]:
>> I think that's already been accepted and understood here.

>
> Apparently not as Alan clearly said "We all know cycling is more
> efficient in general, the question was whether
> that's still true on steep uneven ground where walking may be quicker."


I was just composing a reply to that myself when I read it again, and
relaised that it doesn't make it clear he doesn't understand the issue.

> But I doubt that rough grassy fields are relevant to Artemesia's original
> question.


It emphatically isn't, but that wasn't what Alan was talking about.
Thread drift, if you can imagine such a thing! ;-)

> As for tired muscles, the evidence is that the efficiency does not
> change, the muscles just get limited in the energy throughput, consuming
> less energy and putting out less energy.


Which is what I've supposed all along, but do you want to get the top of
the hill in the most optimally energy efficient way, or the most
subjectively /comfortable/ way right there and then? I, and I suspect
Artemesia, and the majority of other cyclists will prefer the most
subjectively comfortable way, even if it's slower. And especially if
it's quicker.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email protected] http://www.dundee.ac.uk/~pjclinch/
 
Peter Clinch <[email protected]> wrote in
news:[email protected]:
>
> Which is what I've supposed all along, but do you want to get the top
> of the hill in the most optimally energy efficient way, or the most
> subjectively /comfortable/ way right there and then? I, and I suspect
> Artemesia, and the majority of other cyclists will prefer the most
> subjectively comfortable way, even if it's slower. And especially if
> it's quicker.
>


Ah but that's a debate about effectiveness, not efficiency ;-)

--
Tony

" I would never die for my beliefs because I might be wrong."
Bertrand Russell
 
Tony Raven wrote:

> Ah but that's a debate about effectiveness, not efficiency ;-)


Indeed, but I will go so far as to suggest the possibility that
Artemesia is primarily interested in "effectiveness", even if she /said/
"efficiency".

There are times when it's useful not to be wearing one's physics hat...

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email protected] http://www.dundee.ac.uk/~pjclinch/
 
Peter Clinch <[email protected]> wrote in news:5kd385F34a0gU1
@mid.individual.net:

> Tony Raven wrote:
>
>> Ah but that's a debate about effectiveness, not efficiency ;-)

>
> Indeed, but I will go so far as to suggest the possibility that
> Artemesia is primarily interested in "effectiveness", even if she /said/
> "efficiency".


No she was definitely wearing the physics hat with postulating "ideal"
cycles with infinitely low gears and not limited by falling over ;-)

>
> There are times when it's useful not to be wearing one's physics hat...
>


But physics hats are great for getting a thread going - almost as good as
polystyrene hats ;-)

--
Tony

" I would never die for my beliefs because I might be wrong."
Bertrand Russell
 
On 7 sep, 15:28, Peter Clinch <[email protected]> wrote:

> Which is what I've supposed all along, but do you want to get the top of
> the hill in the most optimally energy efficient way, or the most
> subjectively /comfortable/ way right there and then? I, and I suspect
> Artemesia, and the majority of other cyclists will prefer the most
> subjectively comfortable way, even if it's slower. And especially if
> it's quicker.


Exactly - I guess I didn't phrase my initial question correctly. I
should say, for the same speed and distance uphill, which will get me
less out of breathe, walking or cycling?

I hadn't considered the energy throughput, just the energy output.

Cheers,

EFR
Ile de France
 
Artemisia <[email protected]> wrote in news:1189175506.087339.182640
@d55g2000hsg.googlegroups.com:

> On 7 sep, 15:28, Peter Clinch <[email protected]> wrote:
>
>> Which is what I've supposed all along, but do you want to get the top of
>> the hill in the most optimally energy efficient way, or the most
>> subjectively /comfortable/ way right there and then? I, and I suspect
>> Artemesia, and the majority of other cyclists will prefer the most
>> subjectively comfortable way, even if it's slower. And especially if
>> it's quicker.

>
> Exactly - I guess I didn't phrase my initial question correctly. I
> should say, for the same speed and distance uphill, which will get me
> less out of breathe, walking or cycling?
>


For me walking because I can walk more slowly than I can cycle. It will
take longer and use more energy but I will be less out of breath doing it.


--
Tony

" I would never die for my beliefs because I might be wrong."
Bertrand Russell
 
On 7 sep, 14:37, "Clive George" <[email protected]> wrote:

> But more importantly with the trike you've got something you can't do on any
> bike : stop and sit there. So you pedal until you're puffed, put the brakes
> on (with locking device/velcro as appropriate) and sit there relaxing, coz
> you can.


Ah, but on the bike I just hop off , you see. When I get huffed, I
stop by the roadside, standing and visible. It's easy to walk the bike
along with me. Whereas that becomes a lot harder with the trike. So
overall, the hill may be easier with the bike, insofar as it's a walk,
with stops whenever needed.

I'm trying to figure out if the trike is an advantage or an
unnecessary bother on the morning commute.

Apart from that, I could also take the bus. ;°>

EFR
Ile de France
 
On 7 sep, 14:44, "[email protected]"

> Now in the case of a steep hill with grass and thus relatively high
> rolling resistance, it may be that the increased rolling resistance
> more than makes up for the difference of cycling not being a weight
> bearing exercise.


I should mention that in the case of my particular hill, there's no
grass; its all smooth tarmac. Its just dark and windey and infernally
steep and there are cars on it. You can tell how steep it is by how
much the cars are stinking - I get practically asphyxiated whenever
I'm passed by one.

But I can see how the presence of grass would complicate the problem
in abstract.

EFR
Ile de France
 

>>
>>
>> So isn't it actually more efficient energy use to walk uphill than to
>> pedal, even if you do have unimaginably low gears and no topple-over on
>> a trike?


> The legs walking up will be a lot more efficient in tranferring the
> power to make forward progress, so I'd assume walking would be the most
> energy efficient way.
> Over to the physicists.
> Alan.



Alan, you are forgetting that the cyclist will be wearing cleated shoes. I
walked up a hill once with these shoes and soon had other problems besides
the hill.

Pat in TX
 
"Artemisia" <[email protected]> wrote in message
news:[email protected]...
On 7 sep, 14:37, "Clive George" <[email protected]> wrote:

>> But more importantly with the trike you've got something you can't do on
>> any
>> bike : stop and sit there. So you pedal until you're puffed, put the
>> brakes
>> on (with locking device/velcro as appropriate) and sit there relaxing,
>> coz
>> you can.

>
>Ah, but on the bike I just hop off , you see. When I get huffed, I
>stop by the roadside, standing and visible. It's easy to walk the bike
>along with me. Whereas that becomes a lot harder with the trike. So
>overall, the hill may be easier with the bike, insofar as it's a walk,
>with stops whenever needed.


Yes, pushing the trike isn't good. So you don't do it. It's a different
approach - rather than walking, you stop, relax, then ride again. Or indeed
ride _really_ slowly - which you can, because there's no need for balancing.

>I'm trying to figure out if the trike is an advantage or an
>unnecessary bother on the morning commute.


I think the only way you'll find it out is by trying it. I reckon the trike
will be less efficient than the bike, but other factors may make it more
effective for you.

cheers,
clive
 
In article <[email protected]>,
Artemisia
[email protected] says...

> Exactly - I guess I didn't phrase my initial question correctly. I
> should say, for the same speed and distance uphill, which will get me
> less out of breathe, walking or cycling?
>

On a tadpole trike on road in the right gear I reckon pedalling should
easily win (especially if you factor the dismount/remount time into the
speed calculation), but if you pick the wrong gear you might get puffed.
 
Artemisia <[email protected]> wrote in news:1189176557.361981.144840
@r34g2000hsd.googlegroups.com:
>
> I should mention that in the case of my particular hill, there's no
> grass; its all smooth tarmac. Its just dark and windey and infernally
> steep and there are cars on it. You can tell how steep it is by how
> much the cars are stinking - I get practically asphyxiated whenever
> I'm passed by one.
>


You need one of these:
http://www.egopt.co.uk/

Users report double takes from people as they pedal seemingly effortlessly
up steep hills

--
Tony

" I would never die for my beliefs because I might be wrong."
Bertrand Russell
 
On 7 Sep, 13:44, "[email protected]"
<[email protected]> wrote:
> On Sep 6, 7:09 pm, Artemisia <[email protected]> wrote:
>
> > Peter Clinch wrote:

>
> > > I recall one incident when a pal and I were taking our MTBs up a fairly
> > > steep grassy field. I got bored at walking pace, and decided I'd walk.
> > > While walking, I soon overtook my pal, still spinning happily in 1st...

>
> > So isn't it actually more efficient energy use to walk uphill than to
> > pedal, even if you do have unimaginably low gears and no topple-over on
> > a trike?

>
> > I'm thinking perhaps the only advantage of trying to pedal up my hills
> > is the inconvenience of trying to stand up out of a recumbent...

>
> > EFR
> > Ile de France

>
> Cycling (particularly on a recumbent!) is not a weight bearing
> exercise like walking. That is to say, cycling up a hill requires you
> to only move your center of mass up the slope, not carry it. When you
> carry something up a hill you need to not only move it up the slope,
> you need to support it's weight the whole time too. Think about
> carrying rocks up a hill with a wheelbarrow vs a backpack. When
> cycling the center of mass stays pretty still and thus follows the
> slope of the hill without too much extra energy spent. Walking makes
> the center of mass bob up and down a bit which uses energy that
> cycling doesn't. Cycling has the added weight of the bike, and the
> resistance of the drivetrain, rolling resistance, and wind resistance,
> but in terms of calories per distance at slow speeds where wind and
> rolling resistance are minimal, cycling will always be more efficient.
> At high speeds where the exponential wind resistance is much greater,
> one needs to expend a lot more energy to overcome this resistance, and
> then walking is more efficient in terms of calories per distance. A
> lot slower too!
>
> Now in the case of a steep hill with grass and thus relatively high
> rolling resistance, it may be that the increased rolling resistance
> more than makes up for the difference of cycling not being a weight
> bearing exercise. Gearing and what is a comfortable range of cadence
> and force generation for the leg muscles comes into play too.
>
> If you try pushing someone on a bike on a flat feild of grass you can
> see how much resistance there is. And since it seems that riding up
> this hill vs walking was more or less a wash despite the extra rolling
> resistance, this suggests to me that cycling is that much easier than
> walking by the same amount of effort it took to push the person on the
> grass. (That made sense to me at least...)
>
> Joseph


cycling up steep hills is less efficient than walking.ive seen many
mountain bikers riding,legs spinning round,hardly moving,whilst
walking i have also passed bikers on the mountains.ive even seen
cyclists in very low gear on the road,in too low a gear,legs going
round like mad,hardly moving,very innefficient,one turn on my gear on
a racing bike leaves them standing.i think some of them dont want to
put any hard effort into cycling.ive also seen bikers on low gear
dawdling along,no physical effort being used,they cant be benifiting
physicaly in fitness riding that slow.god forbid if they ended up on a
hill on a cycle track.
 
gary2006uk <[email protected]> wrote in
news:[email protected]:

> cycling up steep hills is less efficient than walking.ive seen many
> mountain bikers riding,legs spinning round,hardly moving,whilst
> walking i have also passed bikers on the mountains.ive even seen
> cyclists in very low gear on the road,in too low a gear,legs going
> round like mad,hardly moving,very innefficient,one turn on my gear on
> a racing bike leaves them standing.i think some of them dont want to
> put any hard effort into cycling.ive also seen bikers on low gear
> dawdling along,no physical effort being used,they cant be benifiting
> physicaly in fitness riding that slow.god forbid if they ended up on a
> hill on a cycle track.
>


You've mixed up lots of things that have nothing to do with efficiency
and some that do and you have the wrong way round. For example spinning
quickly is more, not less, efficient than your "one turn on my gear".
Speed has nothing to do with efficiency unless you are starting to go
fast enough to introduce air resistance. Those fast spinning cyclists
you deride are probably getting up that hill far more efficiently than
your wasteful technique.

--
Tony

" I would never die for my beliefs because I might be wrong."
Bertrand Russell
 
Tony Raven wrote:
> Artemisia <[email protected]> wrote in news:1189175506.087339.182640
> @d55g2000hsg.googlegroups.com:
>
>> On 7 sep, 15:28, Peter Clinch <[email protected]> wrote:
>>
>>> Which is what I've supposed all along, but do you want to get the top of
>>> the hill in the most optimally energy efficient way, or the most
>>> subjectively /comfortable/ way right there and then? I, and I suspect
>>> Artemesia, and the majority of other cyclists will prefer the most
>>> subjectively comfortable way, even if it's slower. And especially if
>>> it's quicker.

>> Exactly - I guess I didn't phrase my initial question correctly. I
>> should say, for the same speed and distance uphill, which will get me
>> less out of breathe, walking or cycling?


> For me walking because I can walk more slowly than I can cycle. It will
> take longer and use more energy but I will be less out of breath doing it.


But she says "at the same speed".

It's still not a black and white answer, because your muscles
aren't all working in a common pool in a precisely similar way
between the two modes so it's not just a case of working out the
energy needed.

There will be times when walking will work better, and there are
times when cycling will work better. Variables include the hill,
the wind, your tiredness, how fast you can hit the bottom of the
hill, how gung-ho you feel at the time, and so on.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email protected] http://www.dundee.ac.uk/~pjclinch/
 

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