Does biking help your running

Welcome to BT!

For what it's worth, you are opening a can of worms, as there are frequent discussions on this topic around here, and opinions are all over the map. The general summary of the typical discussion is:

-- Biking may contribute to running fitness for folks who are starting out and who can benefit from any form of cardiovascular training (you probably don't fit that category)
-- Biking can be a lower-risk way of burning lots of calories to get to race weight (you likely don't fit that one either)
-- For well-trained runners, the science doesn't show clear evidence of a cross-over benefit [and people vary in how compelling they find that]
-- Plenty of anecdotal reports from people who think that cycling has helped their running (I would count myself in that group)

If your goal is to get in shape for triathlons, then it's time to get on the bike, and you'll want to be riding rather more than 30 mpw. 100+ would be good for somebody at your level of fitness. But it sounds like your main goal is the marathon right now. I don't think that 30 mpw of easy biking is likely to do much for your marathon, except possibly as a form of recovery exercise after a bout of harder/longer running. My own experience is that I find that hard cycling workouts contribute to my run preparation, as I am much better able to do those than harder run workouts, due to injury risks. On the bike I can accumulate a lot of time at a high HR, with much lower risk of injury, so I think that makes it easier for me to benefit from my no-speedwork run training. I'm sure I would get more from doing run speedwork too, if I could do that without getting hurt. So doing the high intensity stuff on the bike is a compromise.

I crossed over to biking for running last spring after getting sidelined with plantar fasciitis. I went all summer primarily on the bike and have only recently built my running mileage back into the 40-45mpw neighborhood. I was toying with having a go at a sub 3 prior to the injury, but was still in the 3:10 ballpark, so I had a way to go.

I've now switched my ambitions to the tri, and have spent the fall working on my swim. I'll jump to a 12 week Pfitz plan in late February for a May marathon.

Here's what I noticed coming off of a summer of biking and back into a build for running miles:

I can tax my legs, as is suggested as well, with a nasty bike workout and then go for a long run or medium long run still impacted by that workout ... simulating running on fatigued legs, but not having risked injury as much. I did a 90 minute bike workout yesterday ... no intervals, just a long steady ride ... and felt like I was running through molasses at an 8:30 pace for today's 15 mile run. If I take that sort of cycle through a nice taper, I have to think my late stage marathoning is going to be impacted for the positive.

But as has already been stated, 30 mpw on the bike isn't necessarily going to see you any significant running gains at the mileage you're running. From the people I know who were successful at finally going sub 3, they did it with very high mileage ... if sub 3 remains your primary goal, I think I would focus on the run training and, as has been stated, use the bike for recovery gains for the time being.

I think that it doesn't matter what side of the various debates that Colin mentioned you are on to decide the bolded part.  An additional (well conceived) 10mpw running will benefit your running far far more than 30mpw biking (which, to be honest, will not do much for your biking either after a few weeks).

Why do you assume the OP has 'junk miles' in there?  And cycling is not recovery.  It is training.  If you want to recover, recover.  If you want to train, train. 

If you want to be the best runner you can be, run.

It depends on a lot of things...everything from your base, to your running and cycling abilities, to how much of each you are doing and what you're doing.

In GENERAL, I would say, if you want to run better...run. Run more, run smarter, run harder/easier/some balance, but run.

That being said, for some folks, in some cases, adding in cycling (as long as it doesn't act as a detriment to the running) will benefit them.

I completely agree, Brian, but in the interest of fairness, there are some decent studies showing a slight crossover effect, even with experienced runners (though less so for them).  At the risk of opening a can of worms, *I* think that many people tend to over-state the extent of the effect, which, to repeat, is slight (in the studies).

The effect of 30mpw biking for somebody sniffing at sub 3 and running 60mpw, though, would be nil, as opposed to the very good effect that an increase of 10mpw running could produce.

Meulen - 2011-12-19 10:54 AM

JohnnyKay - 2011-12-19 9:02 AM

Meulen - 2011-12-19 9:26 AM

marath7 - 2011-12-18 12:52 PM thanks for all the great replies. After 60mpw I am getting a little bored with running and that was why I was wondering about whether an additional 10 miles would help as opposed to some biking as a way to mix things up. From the replies I have seen so far sounds like I probably should just focus on the sub 3 and then work on the triathlon. I feel like I can increase mileage without much stress on my body so that is probably what I will do. Thanks again. 

I think you could benefit with some cycling if you do it right. I wouldn't expect to be making big gains cycling. However, some cycling inplace of some of your junk miles may aid in your recovery and benefit your running. I think people forget the importance of rcovery. Some high cadence cycling at 70-80% FTP will not only save you the stress of running impact for a day, but clear the lactic acid in your legs helping you recover and leaving you fresher for your next running workout.

Why do you assume the OP has 'junk miles' in there?  And cycling is not recovery.  It is training.  If you want to recover, recover.  If you want to train, train. 

If you want to be the best runner you can be, run.

I won't debate with you that if you want to be a good runner you need to run. I was addressing the OG's "itch" to tri train. I don't think anyone trains 60mpw w/o some sort of junk miles(which I would consider recovery miles....right or wrong I guess) I'm just saying, if the OG wants to scratch that itch and improve running at the same time it's possible to replace some recovery runs with some easy cycling. I did say, you wouldn't be getting any big gains in cycling, but it would be better than nothing. Just my opinion.

I guess I feel compelled to take issue with the bolded part.  Why would someone running 60mpw necessarily be doing 'junk miles'?  (And what exactly is a 'junk' mile, and why is it 'junk'?)

Not only poor choice of words, but a poor assumption about what 'good' run training entails (lots of easy miles are the core--not junk).  Of course, some biking will better for the OP's biking than nothing.  Odds are that less running will be worse for the running, though.  Whether one is 'better' than the other depends upon the main goal.

Meulen - 2011-12-19 1:15 PM

JohnnyKay - 2011-12-19 11:31 AM

Meulen - 2011-12-19 11:04 AM

highly debateable and poor choice of words by me........sorry

Not only poor choice of words, but a poor assumption about what 'good' run training entails (lots of easy miles are the core--not junk).  Of course, some biking will better for the OP's biking than nothing.  Odds are that less running will be worse for the running, though.  Whether one is 'better' than the other depends upon the main goal.

Awesome.....thanks! I'll make sure my terminology plays nice with the yours in the future. LOL My assumption of the OP's goals from his post is obviously different than yours, and it's hard not to make assumption when the OP doesn't have any logs showing current speed/ability. Again.....sorry I'll refrain from contributing.

Feel free to contribute.  Just expect to be questioned when you make statements others don't agree with. 

You called out replacing 'junk miles' with some biking in order to improve running.  I questioned why you'd assume the OP, in particular, had junk miles to cut out.  Your explanation of why you make that assumption appears to raise a separate assumption about run training that I also question (read: disagree with).  It's got nothing to do with terminology. 

And I've made no assumptions on what the OP's goals are.  If they would like to improve their biking while also continuing to run, then adding some cycling makes sense and may not have a negative impact on their running goals.  If they want to run to the absolte best of their ability, then it's probably wise to hold off on the bike.  Sorry if you took my questions and views of your advice personally.