how much will biking (two 30 mins x5 week) interfere with running training? (Read 1115 times)

Only you will know how the extra workout time makes you feel, and if you still feel recovered for your runs.  One thing for certain, cycling is way easier on you than running.  2-3 hrs on a bike (ROUGHLY) would equal the fatigue of an hour running at the equivalent HR.  At least in this hack cyclist's experience.  

Cycling is a good way to get time in at an aerobic HR without the pounding of running.  It is a good mixer for a 5-day-a-week runner, IMHO.

As for whether it counts as a "rest day" if you cycle...who cares?  The point is not to log rest days, but to get adequate recovery.  So you will have to assess if you are getting adequate recovery.  My opinion is that, unless you are biking too hard, it's fine.

I think it's fine. I cycled to work and back for many years (I work at home now). I shouldn't interfere with running at all - if anything it'll help. Just take it easy when you feel tired - no need to push the cycling. Also - it's presumably the kind of distance that you can run sometimes as well...

I am committing to a 5-days a week training program for an October half. 16 weeks.

 

However, I just began biking to work (three weeks ago) or so. I live 7 miles away from work. My typical biking to work is an avg HR of about 155, which compares to a long run pace for me. I am still getting the strength to really crank it up the hills, so I haven't been actually able to hit a high HR all that easily (my legs give out). To compare, I might do an almost-easy run at an avg of that (long run avg HR 155-160, truly easy pace is like 140's for me).

 

Am I jeopardizing 5-day-a-week running schedule by biking an extra 5 hrs a week? Or am I adding cross training mileage that can only help? Is it still a running rest day if I bike that day?

It COULD help but you cannot substitute it with integrate part of run training program.  If you can, Lance would have been the Olympic marathon champion.  Same with any other form of cross training--they would probably help; but you cannot substitute the most vital part of run program.  I think Spaniel hit it right on (I'll bet he has the practical experience with it while he's injured or something...); it's not so much of HR or whatever; if you really want to get the same--or similar--training effect from biking, you'll have to ride at least 2 hours, more so with 3 hours, equalling with an hour of running.  I remember, in my younger days while being injured, I tried to substitute running with biking and a 2-hour biking didn't feel satisfactory and, with my unscientific unsophisticated approach, figured about 3-hours of biking equals an hour of running.  But, by then, my butts took too much pounding (or rubbing or whatever you may want to describe it) and weren't too happy about it.  

I don't know what your situation is but if running a half marathon, and do it well, is your goal and, for whatever the reason, you just HAVE TO ride a bike to work, why not alternate with riding a bike and running?  So you'll ride a bike (7-miles) to work; leave the bike there and run home; run to work the next day; ride it home...  Probably 7 miles a day is plenty of distance for you but 14 is too much; if you want to go a bit further, you can always take a detour and go a bit longer..., etc.  

As long as you're doing 5 hours EXTRA biking on the top of whatever necessary running workout you're doing, you're probably NOT jeopardizing it.  Of course, you may need to make sure it's NOT over-tiring yourself.  A few weeks ago, I went for a run AFTER I mowed--it takes about 1:30 to complete--and I was completely beat so it wasn't a good idea.  This weekend, I went for a run BEFORE I mowed.  A few years back I used to mow only a portion of it, about 30min. each, and used it as warm-up to my running and it worked fine though my wife didn't like it because sometimes I couldn't complete the whole thing (rain, etc.).  Thirty minutes of mowing didn't bother my running but 1:30 is too much.  I don't know if 7-mile biking is too much for you or not.  When Sydney Maree came to US from South Africa, he wasn't used to running on roads and he didn't have a car so he would ride a bike to a golf course and run around and ride a bike back.  So it can't be that bad.