Originally Posted by
MDcatV
You should be able to, but your cycling will definitely suffer. It has to. If you are committed to running the marathon, then I would recommend scale back the intensity on the bike and use cycling only as recovery/low intensity aerobic, otherwise your potential for injury/illness will go sky high.
Running, I'd recommend, dont do too much too soon. With aerobic fitness in the bank from cycling, your lungs will feel like you should be able to run more than your legs can handle, and you're going to be stupid sore - especially going down steps - for a few weeks. When in doubt, do less. Look through some running forums, those dorks are always injured, and you dont want to end up there. That would jeopardize your marathon as well as your bicycle racing season.
Bonus, running sucks so much that you'll really be motivated to get back on the bike and tear it up come racing season.
Gotta agree with a lot of this...again, be smart, listen to your body and increase mileage carefully...I used to be one of those running dorks who now has a worn out left hip and can't run anymore (and I had a few other injuries along the way)...cycling is the only sport so far that I can do without pain (aside from the pain one must learn to love in a race)...also, the comment about soreness going down steps has some subtle value as well...the killer part of a marathon can be, after mile 16 or so,
when going downhill, more so than when going up hill as your quads are being hammered when going downhill, e.g., in Boston, I was cruising through the first 22 miles, up and over Heartbreak Hill, past Boston College, no problemo, then the course dropped and my quads totally tightened, ouch!!! Technique can help...just something good to be aware of...if the course is flat, then probably no worries...