CdCf

If you're an experienced runner AND cyclist, please help me to find a sort of equivalency factor between the two.

In terms of effort (how tired you feel during the event, as well as after), what distance cycled is roughly equal to running a full marathon?

Does that relationship, whatever it is, hold for substantially shorter distances as well?

TomM

I run and cycle and find that cycling allows me to work at a higher intensity level and still not feel as tired when I run.

Pat

Running and cycling are pretty different so I think searching a distance equivilence factor is not really viable.

If you look at running and cycling based solely on calorie expenditure, a marathon is similar to about a metric.

But looking at calories does not take into account that running is a high impact sport. How many people have you heard of who have run marathons two days in a row? I know of bike rides where all the riders, including the not so fit, ride four centuries in a row. I think much of the "fatigue" caused by running is good old wear and tear and possibly even minor injuries.

There are other differences between running and cycling. Running is pretty relentless. I mean you have to keep well running. In cycling, even if you are riding pretty hard, there are times when you coast such as down hills or at stop signs and times when you back off a tad, such as when you are drafting. Also in cycling, you can drink and even eat whilst riding. Another thing about cycling, is that the penalty for being chubby really is not that big unless you are climbing hills. Rather plump cyclists can be really strong riders.

Pat

zowie

What's the basis for that statement? I find that hard to believe based on the relationship of time and intensity for them, but I don't have any real numbers.

donrhummy

Exactly. Cycling (if done properly on a well-fit bike) has very little impact on your joints, ligaments/tendons. Running, especially running on concrete, is a very destructive activity with regard to those parts of the body. I think that's why people find it easier to complete a century than a marathon - not because aerobically it's easier, but less destructive

blue_nose

I used to be a pretty decent long distance runner, but had to scale back on running after some knee problems. Although both activities do have a great deal in common in terms of anaerobic expenditure, I really do believe that running is a much more strenuous event. Running and completing a marathon requires a great deal of training and really cannot be completed by a person that is not quite fit and prepared for the event. Although you can say the same thing for a bike century, an average cyclist can complete this event with as little as a couple of months of training. A have a friend that completed a century after 3 weeks on a bike. I just don’t think this would be possible in a marathon.

The big equalizer here is the elevation on a bike century. A hilly century can be very difficult and a think the most similar to completing a marathon – maybe even a little more difficult.

A lot really depends on the intensity of the ride. If you are complete the ride with little time off the saddle, and at a consistently hard pace then it is more equivalent to running a marathon where there are generally few stops in the run.

DannoXYZ 

Well, they both take about 3-4 hours and burns up about 2500-calories (metric is 62-miles).

What's hard to compare is the muscle-exertion forces and times. Cycling tends to exert the muscles smoothly and continously,whereas running exerts them in high-force spurts. Each push when running loads the muscles higher than in cycling, with a lot of dead time in between. Average power-output may be teh same, but the muscles are being stressed more. You'll end up more tired at the end of a run that burns off the same number of calories as a bike.

Enthalpic

For me I say it is about an 8:1 ratio. A 10Km run makes me as sore as an 80km ride. I would say doing a double (200miles) is about the same as a marathon. It’s a much longer duration but far less damaging.

CdCf

I do realise that there are several major and minor differences between running and cycling. But I was really only looking for a highly subjective opinion. How sore you are during and after is a fairly good indicator. Enthalpic's reply was pretty much what I was looking for.

The reason I ask is partly out of curiosity, but also because I'm going to try to get into running this year. Knowing roughly how running compares to cycling should be a rough guide to what kind of distances I should realistically be able to run once I'm fairly experienced. Not this season, but maybe next year.

sam.g

Since you ask... I just finished my 9th marathon yesterday and I'm sore as hell today. No way could or would I run or cycle today. Hoping to take spinning class on Wednesday evening to loosen up. As others have voiced I don't think that there really exists an accurate comparison as running is a weight bearing activity and entails serious impact stresses to your skeletal and muscular system straining your joints and tendons. I've ridden back to back centuries and even 163 miles at one time but I can't imagine running back to back marathons. Since you really can't isolate the impact stresses from the exersion, I really can't estimate an equivilent distance in cycling to a marathon. I'm sure that there exists an equality measurement for the exersion and calories expended for both, but it would be very specific to the individual, the terrain and the intensity of the effort.

I've also found that running a marathon takes considerably more training than say preparing for a century. I'm still trying to discover a short cut, but have found that nothing takes the place of putting in the miles.

Sam in Cincy

kf5nd

more reasons for me to never run

blue_nose

Elevation on a ride varies so much ride to ride, it is very difficult to come up with any sort of rule-of-thumb / adhoc comparison. Riding a reasonably flat double-century may feel easier and less stressful on your body than a hilly century.

My two cents is that a century with about 8-10,000 feet of climbing is pretty equivalent to how I felt after running 26 miles.

Hope this helps.

CdCf

To get 8-10 000 ft of climbing inside a century here, would probably require a one-mile loop over a local hill, times 100!

blue_nose

The only way to get anythng close I would imagine is to try and ride a century at a very quick tempo pace. There is always a chance of a headwind for an extended period of time

Summit

I just watched an Ironman and it got me motivated to start running too. So I went out for my first run a week ago. Did 6 miles at about an 8 min/mile pace. I'm in fairly good cycling shape, riding 1-2 hours per day, so I didn't think a run of less than an hour would be too bad. The run felt good. My legs were tired after it, but not too bad. And then I tried to get out of bed the following morning and couldn't move my legs. My legs were litterally sore for a week! I can ride a hard pace for many hours and not be sore, but a 45+ min run put me out of commission for a few days. My next run (if it happens) will be shorter.

ericgu

+1.

The cycling intensity curve goes way down. There are some people who ride an 8-hour century, which is a really low intensity. With running, slowing down helps, but you still put out a considerable amount of effort.

DannoXYZ 

Yeah, because no matter how slow you run, you still have to catch the vertical fall of your body-weight with each step...

Garfield Cat

Running effort is more difficult and subjectively it depends on your body type and age. Cyclist can be older and ride quite well. But most cyclists don't like to run unless they were runners before becoming cyclists. I think when you're dealing with running and cycling, you're focusing mainly on the slowtwitch types. These are the long distance runners and if they cycle, they would not be the type that would transition quickly from a comfortable pace to an all out sprint. Runners who are sprinters or quarter milers, are the fast twich types who can hammer on the sprints and mash the gears.

Another thing I noticed is that cycling helped my swimming. The aerobic fitness actually works well in the pool when I attempted to swim laps. This weekend I'll be on a trip so the hotel pool will substitute for my ride. Its great to cross train.

derath

AMEN to that

ranger5oh

Im both a runner and a cyclist, and I have to say its probably at least a 4:1 ratio. Running 1 mile is about where I am at at 4 miles on my bike... but as time goes on, it changes... its not a linear curve.

Last thing I did was a half marathon(injured myself), finished in just under 2 hours. To get the same feeling on my bike, I would have to do 50 miles in about 3 hours, with moderate hills.

The biggest difference like everyone else says, is the "impact pain". After running, your joints and bones hurt, and after cycling its just muscle soreness.

sunofsand

That is a hard comparison to make. Bikes are very efficient. I don't know the efficiency of a human running. All I know is that one revolution will take you a greater distance than the 7 feet or so you may gain in a single/double "stride" -doubt that is the correct term. I would estimate something somewhere between 1:3.5 and 1:20 depending on which gear you're in and distance traveled. You can't truly sprint for more than 400 yards on legs -that's being nice- yet on a bike you may be able to do so for 1/2 mile or more -that may also be nice-
I would say that it is easier to run up a hill than ride up one since you get to use more muscle groups and can shift weight forward easier than on a bike. I'd also say that after a few large hills the bike will win out in that regard. A good runner can keep pace with an average cyclist for longer than the cyclist would like to admit. -you can put your feet to ground faster than you can pedal.
Riding a hundred miles is not a huge feat while completing a marathon is. I can go out right now after riding 60 miles today in the heat and do 100 more ..eventually. I am not sure I could run 26 miles unless my life depended on it. -That is 100 miles of actual pedal time and 26 miles of actual running ..no matter the total distance traveled. I would say 100 miles of -constant pedaling- is equal to 25 miles running and perhaps much less than that. You tire quicker running because you have to load up each stride while cycling is a more constant demand with less extreme contraction. I would liken it to driving a car in the city and driving a car in the country.
The most I have ran at one time is 15 or so miles back in 8th grade. I was a sprinter.

Pat

Shoot, a person who knows how to pace themselves can ride a century with no training. We had people do the quad century every year and that was the only time they got on their bikes. Of course, they rode their bikes very slowly. I rather doubt that anyone could run a marathon on zero training. But if someone were to run very slowly wouldn't they be "walking"?

As I said before, there are fundamental differences between the events.

If you read the comments, many people are talking about the pain factor in running. The pain factor has to do with the damage the body takes from the high impact nature of running itself. Bicycling is low impact. Pain, by its very nature, is subjective so I can not see how anyone can really come up with an objective comparison of the two beyond a statement like "to me running a mile hurts as much as riding 4 miles".

Pat

blue_nose

Read the post. I said the elevation is the equalizing factor. I agree what you are saying, but somebody with little or no training is not going to be able to climb 10,000 feet over a 100 miles at a good pace.

I am not sure what the heck you are trying to say, as I said in the post you quoted that a century really does not require much training - not like a marathon.

CdCf

I'm sure I could walk a marathon if I tried. Walking at just below 4 mph on average, it would take me maybe 7 hours. I've walked about half that once, at a slightly higher pace (4.5 mph), and I felt pretty good after that. Only a slight pain in the neck/shoulder area due to bad posture.

The impact factor is the main obstacle when it comes to running, as you say. I know that. Pretty good replies anyway!

The main reason I want to get into running is that it provides good aerobic exercise virtually anywhere! I only need to carry shoes and light running clothes with me. Easy compared to bringing a bike...

CdCf

I actually specifically asked for a subjective comparison!