What is the equivalent...

[Melvil]

And you're right, very interesting answers. So we have been 3.5miles and 8miles cycling for every mile run. As you and they say, it does also depend on intensity of effort and gradients, too.

 

[Andy in Sig]

Well done Melvil, good to know that there are some clever buggers around!

 

[red_tom]

I did the London Marathon and the Marmotte in the same summer a couple of years ago. I had trouble walking for a couple of days after both.

 

[Flying_Monkey]

why would terrain make any difference?

a marathon is a marathon. not all are on dead flat surfaces

Err, no. A marathon run over mountainous terrain would clearly be significantly different to the Olympic type which tend to be at most over slightly rolling terrain and mostly pretty flat.

100 miles of mountain sportive would be comparable to the physical effort needed for 26 miles of Olympic-style marathon, but 26 miles of fell-running would probably be much more taxing.

 

[rich p]

I have run a sub 3 marathon on tarmac and could barely walk downstairs for a week.
I have run a 72 mile, 23h 50m, 42 peak challenge in the Lake District called the Bob Graham round and felt the same.
The longest cycle I've done is a 114 mile sportive in the Rhone Alpes and could almost have done it again the next day.
There is a massive difference between the damage you do to your muscles running on tarmac and offroad so it's very difficult to guage a sensible comparison of effort.
There is also a massive difference in both sports if you're running within yourself. If you're doing them eyeballs out then a road marathon would equate to 200 miles on the bike IMHO. But that's a guess!

 

[Andy in Sig]

I think you've just illustrated the key point. The difference in effect is huge due to, as somebody has already pointed out, running being an impact sport and cycling not. Therefore it seems to me that the the sensible thing to compare is energy burned.

So is there some equation where, having worked out the energy needed to shift, say a 10 stone body for 10 miles at 7.5 minute miles (I'm guessing that that might be an average speed for the not superfit), you can say that to use up the same kind of energy moving a 10 stone body on a bike on the flat you need to do X miles at an average, say, 15 mph?

 

[walker]

Err, no. A marathon run over mountainous terrain would clearly be significantly different to the Olympic type which tend to be at most over slightly rolling terrain and mostly pretty flat.

100 miles of mountain sportive would be comparable to the physical effort needed for 26 miles of Olympic-style marathon, but 26 miles of fell-running would probably be much more taxing.

thats the point Iwas trying to make