analog_kid86

My marathon running girlfriend asked me a question recently. Is riding a century comparable to a marathon in terms of physical demand? Is there some type of conversion?

gregf83 

It all depends on how fast you ride. A seven hour century might be like completing a marathon but only running a portion of it and walking the rest. The minimum level of effort required to run a marathon without walking might equate to a 5 hr marathon. I don't know if those numbers are exactly correct but the point is it's possible to ride at a much more leisurely pace than it's possible to run.

I don't know how to convert exactly but you could look at the times for Ironman finishers. The winner this year (Chris Lieto) did a 4:37 bike (112 mi) and 2:48 run. Hard to tell if he worked harder on the bike than the run.

Apart from energy output running is much harder on the body. Marathons require more recovery.

chadwick

I've had a few centuries that were harder than the marathon I've done, but those were unusually epic days (i.e. horrible, horrible wind or a ginormous mountain or 3 to go over).

Going from 'couch' to century is a whole lot less training time than going from 'couch' to marathon, in my own experience.

In both cases, going really, really fast makes the experience much, much better.

DataJunkie

It is very difficult to make a blanket statement such as one is automatically harder than the other.
There are too many variables.
So... it depends.

abdon 

Wait, she is the runner, and you are the cyclist, right?

Then of course riding a century is way harder!

Feel free to slap your forehead as you read this

chasm54

Conversions are difficult because the two exercises make very different demands on the body. Running is a weight-bearing exercise, cycling is not - most of the time.

In terms of energy expenditure, however, it is possible to make a comparison. Cycling at 12 mph consumes a similar amount of energy per mile as does walking at 4 mph. At faster speeds, the gap narrows because the air resistance becomes more significant for the cyclist - it takes much more than 20% more power to maintain 25 mph than 20 mph on a bike for this reason.

However, if you want a rough equivalence and your marathon-running GF does her marathon in four hours, she'll consume as much energy as she would in riding about 70 miles at about 18 mph. But she'll feel much more beaten up by the marathon because of the wear and tear of impact. On the bike, the machine carries your weight and you just have to propel it along.

Juha

The question comes up often in the Forums. A couple of earlier threads on this subject:

https://www.bikeforums.net/showthread...ing-a-marathon
https://www.bikeforums.net/showthread...-of-a-marathon
https://www.bikeforums.net/showthread...ing-comparison
https://www.bikeforums.net/showthread...ing-vs-Cycling
https://www.bikeforums.net/showthread...ing-a-marathon

--J

travelmama

Exactly.

Pat

As mentioned above, running is weight bearing and also pretty high impact. Cycling is none weight bearing and low impact. I think the energy required to ride a century is about 50% greater than running a marathon. But even chubby people can ride centuries well and there is a really big penalty for weight in running.

Also the wear and tear in a marathon is much greater. The impact beats up the feet and knees. You don't hear of people running back to back marathons. I have seen large organized rides that featured 4 centuries on successive days. I have talked to people who have ridden across the country averaging more than a century per day for a month. Then there is RAM.

Because cycling is so much easier on the body, a cyclist can do far more riding over time than a runner can do running.

The sports are very different.

thedutchtouch

according to the NY times, lance armstrong once called the marathon the "hardest physical thing" he's ever done... https://well.blogs.nytimes.com/2009/1...lks-marathons/

jmX

Ive done a half dozen half marathons, and a couple centuries (only started riding a few months ago, so I havent done many).

I feel that a half marathon was pretty close to the century I did with 3000ft of elevation gain. Of course as others have mentioned, the pace is everything. I was pretty slow in both (2h 10m half marathon with the wife, vs 6h 29m century), so I think that may be why I felt about the same after completing each event.

I can say that riding a century is more fun than running 13.1 miles.

A full marathon to me sounds like hell, much like a double century sounds bad to me at the moment.

hobkirk

It's hard to compare the two efforts. I was a runner and somewhat serious about it (2:52 marathon at age 40, 6 1/2 minute pace), and I was very focused on my pace. I would force myself to throttle back for roughly the first half and then gradually start pushing until by the end I was on the verge of cramping both quads and calves. I did two centuries on consecutive weekends in my fourth month of cycling (both 15.3 average, very tough on the second one, age 65). The second century left me pretty stiff, although not nearly as bad as my marathons had (I needed to go backward to go down stairs for several days) and I did flirt with cramping. But, despite the intervening years (and waning body) I think I can make an observation.

I find that one large difference is that hills prevent me from pacing myself on a bike the way I could when I ran - the difference between flats and climbs seem much greater in cycling than running. It "feels" to me that it's possible that a runner can get closer to the edge of collapse without endangering himself than a cyclist. but I am too much of a novice to know.

PS - I find it quite remarkable just how many hours a cyclist can push very hard. My reservation about cycling as exercise was my perception (possibly wrong?) that it seemed to take about twice as long as running to get the same effect.

tallmantim

Looking at this:

https://www.runtheplanet.com/resource...riecounter.asp

it says that for me I would burn about 4000 cal in a 4 hour marathon.

At race pace I would burn 1000 cal/hour and manage to do the century in the same amount of time (dependent upon terrain) - so about the same kJ output.

However riding you can replenish cals much more easily and is much less stress on the body (even at race pace).

So I'd have to give the nod to the marathon.

Berber Biker

As an avid high school track and cross country runner, I have trained and competed among top runners. At the peak of my seasons I would run sub-5:00 on the mile and fast 5ks/10ks. Of course my training runs of 10 or 13 miles can't compare to an entire marathon. I am knew to cycling, although I find my performances marginal to those of other veteran cyclists. But back to the point, I personally find distance running to be a whole lot easier. My breathing stays controlled and I can pace myself while running, however not as well with cycling...It seems like the very opposite for others; running is the hard(er) one, and cycling is easier, at least in terms of breathing. If I was to train for a marathon, and train for a century, I would say that the marathon would be easier for me. Cycling, as mentioned above, doesn't tear the muscles and ligaments on your legs, the bike absorbs a lot of it. To answer the question, NO riding a marathon and cycling a century are not comparable...

aham23

thats because he under trained and/or was poorly prepared. if you put in the training there is no way one would say on 3 hour marathon is harder then 3 weeks of TDF. later.

Carbonfiberboy 

You mean you don't hear of it. Dean Karnazes ran a marathon every day for 50 days. Look it up.

So far there is no conclusive evidence that marathon running does permanent damage to the knees or feet. There is reason to believe running may be protective to cartilage.

I think double centuries are fun.

Those who think cycling isn't weight bearing simply don't ride hard enough.

Running and cycling have different emphases. I don't think one is "harder" than the other. They're just different. For most people, riding a century will be easier than running a marathon. I think that's because of the hours a cyclist puts in while acquiring the endurance to ride a century. If a runner puts in the same hours, they'll have a good marathon.