hell no. running is so much less efficient than biking... you think running 30 miles is as easy are biking 90? it isn't.

i'd say it's closer to 1:5 when under five miles of running, and closer to 1:10 when over ten miles of running, with the slope of the curve increasing exponentially.

of course, the athlete's personal physiology and predispositions/proficiencies/strengths will drastically change the distances and amounts. i don't run, so i could probably just as easily bike 60 miles at a strenuous pace as i could run 5. furthermore, i bet i could bike 60 miles at 16mph where i could only run 5 miles at maybe 7, or 8. last time i ran a 5 mile was 13 years ago and i did it in 45'. i'd be surprised if i could break 40' now that i'm stronger and have greater endurance and a much longer stride.

You also have to take into account running/cycling economy. Someone who has terrible form and swings their arms too much/rocks back and forth is going to burn way more calories per mile running than a smooth, efficient runner.

A good "average" that most runners use is about 100 calories per mile. This is regardless of speed, because a person running 9 miles per hour will run a mile in less time than someone running 6 miles per hour, but calories per mile will average out to be pretty close.

There are a ton of variables at play here, but I have also heard that you can do about 3 to 1 (as previously stated) biking to running. But I would think this is for distance, not time.

you guys are really contributing by throwing out these scientifically derived ratios of biking to running miles.

IME, I bike a lot and run a little bit. I bike between 150 and 200 miles a week and run about 15 miles a week. My typical road bike ride is about 40 miles (usually lots of hills, too) and my typical run is about 5 miles. I am more exhausted after the bike.

it all depends: what kind of running, and what kind of biking, how long, how intense, etc? Are you running to something? Are you running from something? Is it a bear? Is the bear an average bear, or Olympian bear?

Considering the apples v. oranges nature of it anyway, the 1:3 rule of thumb (with respect to distance) has always been a decent enough calculation for me, if considering approximately equal levels of effort for either.

I run some mornings maybe 4-5 miles with half minute water breaks every mile, and it definetly wears me out more than a 30 mile bike ride, fixed. Running 400m, 800m, and relays in track is not as draining as say, 3 minutes of heavy sprinting on a bike.

agree with cc, the curve goes up quite a bit - distance running drains you so much more than biking. not that ive ever done a century yet.

and there is no starting ratio (1:3, 1:5). Someone mentioned before some people can do centuries but cant run a mile in ten mins. that is completely true, sometimes the other way around.

person-to-person, varies between distances.

done.

As an injured runner, running always being my primary sport, I have a good deal of experience using cycling to supplement my training. As far as general fitness goes, running to cycling is roughly a 1:3 ratio in terms of distance. In other words, someone who cycles 15-30 miles per day will have similar fitness attributes to one who runs 5-10 miles per day. Although these two people will not have identical musculature, they will perform very similarly to each other in other activities, i.e. swimming. Obviously, the runner will beat the cyclist running, and the cyclist will do likewise cycling.

For someone who is training for a running race, supplementing running with cycling in training can result in equivalent sport-specific performance gains if the ratio is tweaked to emphasize running, say, 6:1 cycling to running. A 60 mile per week runner will decimate a 360 mile per week cyclist in a footrace, but a runner who does 40 miles per week running and 120 miles per week cycling will be quite competitive, perhaps even having an advantage.

Besides attempting to substitute one form of exercise for the other for performance reasons, cross training in this manner is useful for decreasing overuse injury risks. Running muscles, although not primarily engaged in cycling do help reduce load when cycling-specific muscles are fatigued. The same goes for running.

I hope that wasn't too long for people to read. :thumb:

not if you have vibram fivefingers, they are da bomb

1:3 ratio is completely bs. A cyclist that could do 30 miles rides will have an EXTREMELY hard time running 10 miles.

As would a 10-mile runner cycling 30 miles. The 3:1 ratio is only applicable with a third point of reference, be it swimming, roller-blading, or Frisbee. The runner and cyclist, compared using a tertiary reference, would have similar endurance.

I don't think that's even remotely true.

I'd assert that very few people who are used to running 10 miles would have any difficulty biking 30 miles, whatsoever.

I usually only run 5-6 miles when I go running and I ride 25 miles without breaking a sweat, but I do train for half marathons.

+1

I really wish my ultra-marathonin' buddy would hop on a bike. Dude can do a 140 mile run. Bet he could pull 200-400 miles without issue.

I would think the only thing holding someone like that back would be comfort. If you're not used to being in the saddle for long periods of time it can be a killer.