Cycling as part of marathon training

I´m training for marathons and apart from running 4-5 times a week also cycle to work 5 times a week. It´s 9 miles each way with varying speed (due to city traffic and terrain - some in heavy traffic, some through Richmond Park where I can go much faster). It normally takes me 30-35 mins. How much of it can I count as part of my weekly mileage for running? I.e. If I aim to run 50 miles a week, can I take 10 miles or so for my cycling?


  • Not really.

    Very different leg muscles.

    If you want to run faster - then run more.

    Cycling is good for cardio and hill climbing helps you run uphill a bit - but running miles are the way.
  • I totally disagree. Cycling is great for cross training for running. I would count 2 minutes of cycling as one minute of running.
  • In the oct/nov issue of Trail running magazine there is a 13 week training plan to run a 40 mile race, and some weeks after a 12-15 mile run on a sat you have to do a 21 mile bike ride on sun. Which they say is equivalent to a 7 mile run! The principle behind it is "periodisation training-controlled overloads to help strengthen heart and lungs and to get the body burning fat mor efficiently" hope all that makes sense! 

  • NLR - it's better than nothing but you can't replace run miles with bike miles.

    You'll be undertrained if you use a plan that says run 50 miles per week and you ran 30 and cycled the rest.

    Cycling is cycling. Running is running.

    Id also say that a 21m bike is nothing like a 7 mile run.

    That would mean an 80 mile bike is like a marathon. It's just not.
  • I disagree with you Ultra Cougie. Ok so Mo Farah will not be jumping on his bike to do one of his sessions this week but for runners who struggle to knock out the mileage without getting injured, a cycle ride is a good replacement for a run. RW published a book about 3 runs a week and 2 cross training sessions a week and how runners doing this thrived on it. A cycle is different from a run but there would be no point cross training if it wasn't.
  • if you want to run faster run more (without getting injured).

    You won't find Mo or the Kenyan's cycling.

  • I'm sure there has been a time when a Kenyan has rode a bike
  • Just google imaged Kenyan Cycling and there were hundreds of them
  • But Petr hasnt said he struggles with injuries. He's got a plan of running 50 miles per week, but wants the bike to account for some of those miles.

    He'd be better off having a plan to run XX miles and then just ride on top of that ?

    He's doing about 5 hours of cycling a week.

    50 miles of running would be what - 7 hours or so ?

    If we go with your 2 mins of cycling is worth 1 min of running - he'd knock that down by 2.5 hours  - so down to 4.5hours  - which would be under 32 miles.  A long way off running 50.

    If I ran 50 every week I'd be flying. 

    As it is - I'm usually nearer the 32 but with cycling on top. I'm not flying.

    I've heard Kenya will be the next cycling nation - but I'm not sure. Its a lot more accessible to run than it is to get a bike. Plus I dont think the Kenyans would cope with cold rainy Belgian cobbles.

    (then again I never thought we'd see a Brit win the Tour)

  • Petr

    I agree with Cougie, and with NLRimage

    If your plan for the marathon training is to run 50 miles a week, then I wouldn't reduce this at all just because you cycle to work. Running a marathon requires you to put in serious time on your feet running, and I don't believe cycling is in any way a substitute.

    However, it's definitely true that cycling is a great form of cardio training, and you'll be fitter and less likely to be injured if you do both. Also, if you do start to struggle with maintaining the 50 mile a week mileage, or you start to feel an injury coming on, then I think a bike ride is a good way to try and maintain your fitness while you recover...
  • I'm thinking along the same lines as YP.  Presumably you've been in the cycle commute habit for a while so it's well within your comfort range.  However, when you start ramping up the mileage for marathon training it could take while to get used to the higher overall volume of activity, in which case you might have a case for dropping the odd easy run, and considering the cycling as useful cross-training before you feel ready for your next big running effort.

    That's another thing - not all running miles are equal, which is part of the reason why it's a little misguided to think about running/cycling mileage/time equivalents.  There's absolutely no substitute for time on feet for marathon training, so if there are any compromises on the running mileage it should only be cycling in the place of shorter, easy runs.  Make sure you still get all the long runs in.

  • I always,always agree with PhilPub
  • Thanks, guys. A bit of a mix here but helpful. Cheers!


  • Dr.DanDr.Dan ✭✭✭

    I'm in the camp that thinks that cycling can replace some of the easy "recovery/filler" mileage. Make sure you have the Sunday long run, midweek longish run and a couple of quality sessions - they cannot be substituted by cycling.

  • @ULTRA - I agree with you. especially your first comment.

    for the others yes prob 2 mins of cycling is like 1 minute of running in terms of difficulty BUT as @ULTRA says its different leg muscles. But yes of course both use the same lungs and blood and other various bodily bits and pieces. So maybe's everyone is kinda right??!!??

    FWIW I do a lot of cycling and a lot of running......


    Running 5k Better


    Goals:  82% Age Graded 5k and an open water Triathlon.

  • The BusThe Bus ✭✭✭

    I'm with Dr Dan  - cycling is good for replacing those easy and steady runs, and also for recovery so can be used to make up the miles, but for marathon training in particular you can't substitute the weekly long run or long tempo and speedwork. By replacing some of the easy runs with cycling  though, it does mean you can increase focus and effort on your critical sessions and make those work much better for you.

    The cycles sessions need to be of a good quality though and stretching you aerobically.

  • Sussex Runner (NLR) wrote (see)
    RW published a book about 3 runs a week and 2 cross training sessions a week and how runners doing this thrived on it. A cycle is different from a run but there would be no point cross training if it wasn't.

    Run Faster, Run Less. Basically all 'easy' mileage is replaced with swim/bike/row. So you could follow the plan without cycling at all.

    I subscribe to the thought that if you own a bike there is never any need for recovery run mileage.

  • More to the point who said you need to do 50 mpw to complete your marathons?

    I have been knocking out 3.30 mara times off 25mpw runs and around 100 miles on the bike.

    Everyone is different though i suppose its up to you to experiment.

  • RicFRicF ✭✭✭

    I ran 2:46:51 in the 2003 Abingdon marathon off cycling and averaging 18 miles/wk running for the six months preceding it.

  • I agree with Sussex Runner, I knew someone who did their first rather hilly 10k in 44 minutes, which isn't a bad time for a non-runner.  He was a regular cyclist.  A sub 40 runner probably isn't going to get faster by cycling, but it sure helps with hills if you cycle hard.

    Overall though, to do a marathon you should put some long mileage runs in and see how you get on.  If you can run 15 fairly comfortably, then fine.  If you struggle then do some more running.  I don't think there is a right or wrong way, everyone is different.

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