Cycling equivelant to marathon

[Rob3rt]

So prey where have I misused the laws of physics? Do you disagree that the amount of kinetic energy used to run 26 mile is less than it is to cycle?

If someone wants to break the two sports down to make a comparison (which you rightly or wrongly argue can't be done) then you have to start somewhere, so you have to know the energy required and then develop some formula to take into account effort (be that effort from the nature of the exercise, or external variables, wind resistance etc.)

You have applied an equation for a point mass (which can be extended to include a body with a constant centre of gravity which can be used as an equivalent point mass). Ideally a runner and cyclists centre of gravity would remain in the same plane, however in reality it probly doesnt so the equation is a very rudimentry estimation of the kinetic energy. Also the equation for kinetic energy depends on velocity, which has both magnitude and direction. So if you are wishing to apply this formula, you are talking about moving a point mass, a set distance in exactly the same direction at a given speed. Thats not a very good approximation.

Even in a simple estimation, there are quite a few other things that need to be considered. Its just not worth the time, because even if you could perfect the science, it wouldnt explain the "difficulty" of each activity.

 

[oldfatfool]

You are getting confused about total effort.

You could burn the same calories sat on your arse for a few days as you could running the marathon.

By your rationale the two require the same level of fitness.

Getting bored now, but there is no kinetic energy used in sitting down, and in the last sentence you have quoted I mention that in order to complete the comparison you need to take into account effort required. I have frequently mentioned that running is a higher impact sport, less efficient use of energy etc etc.

If you have read all my posts you will see I came to the conclusion that to compare the two the cyclist would have to cycle between 26 mile in approx 35mins upto covering 80+ mile in 4.5 hours. Hardly sitting still.

 

[Zoiders]

Getting bored now, but there is no kinetic energy used in sitting down, and in the last sentence you have quoted I mention that in order to complete the comparison you need to take into account effort required. I have frequently mentioned that running is a higher impact sport, less efficient use of energy etc etc.

If you have read all my posts you will see I came to the conclusion that to compare the two the cyclist would have to cycle between 26 mile in approx 35mins upto covering 80+ mile in 4.5 hours. Hardly sitting still.

It's calories burned to be exact not kinetic energy.

Kinetic is just a form of expression and transference of energy - and you do BTW transmit kinetic energy just sitting down as your heart beats and blood pumps around your body which is a mechanical process that follows newtons law, that's on top of all the other chemical and electrical processes going on that all use energy.

Sit on your arse for two days or run a marathon, they could both have the same total energy requirement.

 

[oldfatfool]

It's calories burned to be exact not kinetic energy.

What is??

The body burns fuel to work, expressed in calories.

A persons potential energy will depend on the amount of fuel they have, this can be converted to kinetic energy.

K=1/2 M x V[sup]2[/sup]. so to move the same body on a bike for the same length of time at the same speed will have more Kinetic energy and ergo require more fuel than the runner, by the fact that the mass is greater (bike + body)

At no point have I said running is easier or takes less effort, or that the fuel required is purely converted to KE. If that was the case the cyclist would also use 110 calories to cover a mile, Like I expressed using the tables linked in the earlier post in order for the cyclist to burn 110 cals / mile he would have to average 55 mph.

 

[Rob3rt]

What is??

The body burns fuel to work, expressed in calories.

A persons potential energy will depend on the amount of fuel they have, this can be converted to kinetic energy.

K=1/2 M x V[sup]2[/sup]. so to move the same body on a bike for the same length of time at the same speed will have more Kinetic energy and ergo require more fuel than the runner, by the fact that the mass is greater (bike + body)

At no point have I said running is easier or takes less effort, or that the fuel required is purely converted to KE. If that was the case the cyclist would also use 110 calories to cover a mile, Like I expressed using the tables linked in the earlier post in order for the cyclist to burn 110 cals / mile he would have to average 55 mph.

In the same direction, you keep neglecting that velocity has both magnitude and direction.

In terms of the runner, there are several components of kinetic energy, simplistically we could say, both forward, and up and down (to and fro with the gaining and losing of potential energy). So its not as simple as you present it.

 

[oldfatfool]

In the same direction, you keep neglecting that velocity has both magnitude and direction.

In terms of the runner, there are several components of kinetic energy, simplistically we could say, both forward, and up and down (to and fro with the gaining and losing of potential energy). So its not as simple as you present it.

Fair and sensible comment, though there will be an element of the same for the cyclist in the pedaling action.

Originally I must admit the KE argument was a little tongue in cheek to counteract the folks who where saying you would have to cycle a million miles to equate to a marathon. I thought I had clarified my stance on the comparison in the use of the scientific tables, which obviously shows I have no doubt that you would have to cycle bloody intensely to equal the effort of a marathon runner.

I must admit I was astounded that the scientific findings were that a runner only uses 110 cals/ mile regardless of speed, I would have thought heat energy alone would have increased exponentially with the runners speed increase, know I get a lot hotter the faster I have to run!

Look forward to cycling with you sometime............but not running

 

[zizou]

Difficult to compare and depends so much on terrain and pace - running 4 hours in the London marathon is going to be alot 'easier' for the average runner to train for and achieve than the average cyclist being able to do do La Marmotte (108 miles) in under 7 hours. Whereas a flat century in 7 hours is going to be 'easier' to achieve than running a sub 3 hour marathon.

The one thing that is being over looked here is that people who do well at running marathons are runners and people who do well at long distance cycling are cyclists. Is the 100mtr sprint at world record pace harder than a world record marathon time? Is it harder to fight at flyweight or heavyweight? People condition their bodies for given disciplines. If we are to get an good comparison we need to ask a tri-athlete which is harder.

Swimming

However this isn't reflected in the relative distance in triathlons which are biased against swimmers due to the swim leg being ridiculously short in comparision to the other legs - i've seen a few sprint ones with 400 metres as the swim leg, that isn't even a warm up and hardly worth getting wet for. At Ironman distance the ratio between the swim and run is about 1:11....it should really be a max of about 1:4. (Then there are the wet suits which give flotation and drafting being legal in the swim leg but not the cycle...frankly it is a conspiracy against swimmers )

Good point at the body conditioning though, very difficult to compare the demands of one sport to another.

 

[Rob3rt]

Fair and sensible comment, though there will be an element of the same for the cyclist in the pedaling action.

Originally I must admit the KE argument was a little tongue in cheek to counteract the folks who where saying you would have to cycle a million miles to equate to a marathon. I thought I had clarified my stance on the comparison in the use of the scientific tables, which obviously shows I have no doubt that you would have to cycle bloody intensely to equal the effort of a marathon runner.

I must admit I was astounded that the scientific findings were that a runner only uses 110 cals/ mile regardless of speed, I would have thought heat energy alone would have increased exponentially with the runners speed increase, know I get a lot hotter the faster I have to run!

Look forward to cycling with you sometime............but not running

However, the cyclists centre of mass remains relativelly stable when seated despite the pedalling motion, hence they typically would have 1 component of velocity (probly not wholly true, but much less than the runner). Your equation can probly be used as an approximation for the cyclist travelling in a straight line, in a given direction, as a certain speed, but not so much the runner.

 

[Zoiders]

What is??

The body burns fuel to work, expressed in calories.

A persons potential energy will depend on the amount of fuel they have, this can be converted to kinetic energy.

K=1/2 M x V[sup]2[/sup]. so to move the same body on a bike for the same length of time at the same speed will have more Kinetic energy and ergo require more fuel than the runner, by the fact that the mass is greater (bike + body)

At no point have I said running is easier or takes less effort, or that the fuel required is purely converted to KE. If that was the case the cyclist would also use 110 calories to cover a mile, Like I expressed using the tables linked in the earlier post in order for the cyclist to burn 110 cals / mile he would have to average 55 mph.

The bike is a low friction device.

It ups the velocity and striking energy for example if you ride into something by accident it does not however require more fuel to do so.

You are getting newtons law in a muddle again.

 

[MacB]

A big difference is in impact, up the pace from a walk to a run and you up the pounding, but the cycling will remain low impact. The closest direct comparison I can think of would be cycling v a cross trainer.

It's fairly easy to compare energy/effort expended for a marathon and work out an equivalence in cycling distance. But you'd likely feel fresher/better after the cycle as the impact is low.

 

[Angelfishsolo]

A big difference is in impact, up the pace from a walk to a run and you up the pounding, but the cycling will remain low impact. The closest direct comparison I can think of would be cycling v a cross trainer.

It's fairly easy to compare energy/effort expended for a marathon and work out an equivalence in cycling distance. But you'd likely feel fresher/better after the cycle as the impact is low.

Try MTBing instead

 

[lulubel]

I must admit I was astounded that the scientific findings were that a runner only uses 110 cals/ mile regardless of speed, I would have thought heat energy alone would have increased exponentially with the runners speed increase, know I get a lot hotter the faster I have to run!

Science can "find" whatever scientists want to. It takes common sense (like your reference to heat energy above) to recognise when the scientists are talking rubbish and have just manipulated the statistics to get the result they wanted.

 

[Rob3rt]

Science can "find" whatever scientists want to. It takes common sense (like your reference to heat energy above) to recognise when the scientists are talking rubbish and have just manipulated the statistics to get the result they wanted.

What on earth are you on about?

 

[VamP]

Science The deluded can "find" whatever scientists they want to. It takes common sense (like your reference to heat energy above) to recognise when the scientists delusional are talking rubbish and have just manipulated the statistics to get the result they wanted.

FTFY

You are not really on speaking terms with the scientific method, are you?

 

[pubrunner]

A big difference is in impact, up the pace from a walk to a run and you up the pounding, but the cycling will remain low impact. The closest direct comparison I can think of would be cycling v a cross trainer.

It's fairly easy to compare energy/effort expended for a marathon and work out an equivalence in cycling distance. But you'd likely feel fresher/better after the cycle as the impact is low.

+ 1

I've done 14 or 15 marathons, including 5 or 6 which were very hilly (4,000ft climb) and entirely off-road.

For each I trained hard; yet after each one, my body felt 'wrecked'. For days afterwards, just walking is painful.

Back in 2007, I had a go at the Cheshire Cat Sportive (100 miles). I did NO cycling training for it whatsoever. In fact, I'd only cycled 50 miles once, prior to the event, but that had been the year before. (I've never cycled more than 200-300 miles in any year).

Of course, the Cheshire Cat did get hard after about 70 miles, when we hit the steep climbs by Macc. Forest. Towards the end of the ride, I was tired, but what I found, was that I could still keep turning the wheels (albeit at only 10-14 mph) because the bike was taking my weight. I'm sure that I could have gone a lot further, because a big advantage with cycling, is that it is easy to carry & consume food on the move. 'Just keeping the wheels turning' is a lot easier than 'just keeping the legs going'.

The day after the Cheshire Cat my legs felt fine; likewise, after ColinJ's 70 mile ride in Yorkshire which had over 7,000ft of climb.

I sometimes do a training run of 18 miles which is largely off-road and has about 2,000ft of climb. No matter how easy I run it & despite carrying energy drinks, it 'knocks me about' far more than cycling.

I'd estimate that for me, something upwards of 250 miles on a bike would very roughly equate to a briskly run marathon (8 minute miles).