If you haven't read it, get your hands on a copy of Training For Endurance, Edition 2. It explains it all. The book seems to be on back order everywhere. In a nutshell, if you are going to do an aerobic base building period---build your arerobic system--then don't let your HR go over 180-age (minus 5 more if you are coming off an injury). This number is your MAF. Create a zone of MAF to MAF -10. Warm-up at least 15 minutes, gradually getting to MAF -10. Then stay in that zone. Maffetone suggests that ALL your training (bike, running, swimming, etc.) stay in that zone. Do regular MAF tests at least every 3-4 weeks to monitor progress, regression, and stress. In the book, he talks about athletes saying things like your "seems it wouldn't be worth it to bike that slow." He would say it is entirely worth it. The slowness is temporary (if you are not over-stressing the system). You'll be doing everything slowly at first. But that is how it works. Good luck! --Jimmy

Okay, I appreciate the quick responses! That tells me exactly what I need to do, so I'll start wearing my HRM for cross-training, too. I'll perform a monthly MAF Test to monitor progress. Also, the more running mileage I build, the less cross-training I'm likely to do (other than some moderate core exercises). Thanks again! Bill

Jimmy, 6:23 am??? Heck, that'd be 3:23 pst!? Hope you've had some black java, fore ya start ur chores. lg

Do I have this right? I'm coming off of injury (PF), so have been cycling the last couple of months - what I would call very hilly routes at a tempo or faster pace each time. So when I start a MAF running program again soon, I should either stop cycling or cycle at my "maf pace"? Seems like it wouldn't be worth it to bike that slow... I wanted to mostly run and then bike only 2X a week, but running will be my priority. I could also cross train on the elliptical, but should it be at maf pace also? Thanks, Bill OK - I just saw the discussion on how hiking could affect maf, so I'm guessing other exercise like cycling and elliptical might be detrimental to maffing (unless I do all X-training at MAF or below - or am willing to experiment).

Something to keep in mind. Lactate theshold is often reached at a much lower HR on a bike as compared to running. This may differ by as many as 10 beats.

It's definitely typically lower, but from the three people who have sent me their data from independent bike and run vo2max tests, it was between 3 and 5 beats. These were all from triathletes who primarily run, but do a lot of cycling. Could well be higher from non-cyclists. This would effectively drive to a lower MAF value and to be conservative, if one were not well conditioned on the bike, subtracting off 5 beats would be in order. Not sure it's fully necessary though. I did stay conservatively low when I built up my cycling fitness.

The real question is how significant is this lactate level? The RQ (fat vs. sugar burning) actually doesn't change that much. So on the bike, I don't think you should change your MAF. The main difference is you have to work harder to reach MAF on the bike because forces are less (you're not working against gravity as much compared to running, for example). More so in the water. So if you want a 'harder' workout, ride at MAF. It's like running downhill.