Jacko, I've found your idea of biking as a supplement for aerobic
distance to be right on. I've actually found it can be a complete
replacement for easy mileage. I ran four years in college without
stringing more then a month or two of steady training together, my
coach John Gregoric at brown was a great coach, but I was a difficult
case. My shins are incredibly bowed and I could not seem to get going
with training without getting a stress fracture. I had 5 in college
and two just after, coming back from time off was also very difficult,
injuries breed injuries. I managed to run 3:47/3:48 a number of times
in college off this limited training. That's nothing special, but I
knew I had potential and loved running so much I couldn't stop.
Finally after my last stress fracture while I was training with Zap
Fitness in NC, my coach Pete Rea and I decided to try something
completely different. We had been chatting with a triathlete who said
he actually had dramatic drops in his open 5k time after becoming a
triathlete. We decided I could try something like triathlon training
just with a major focus on the running. We started a program where I
would only run four days a week and spin on a stationary bike or swim
laps the other 3. During a running day I would run quality, either a
fairly steady distance run (6:00 - 6:15 pace) or a workout. The biking
days were on the same days that the other guys on the team did easy
distance. I would bike almost exactly the way 'backstretch' advised.
120-130 RPMs at a low resistance level. This way you will work your
lungs without building biker muscles, it does also help your
cadence/turnover. I started this program in late March last year, by
early June I had dropped my 1500 time from 3:47.9 to 3:42.5. I
continued it this fall. My best 8k time in college was 25:12, I ran
under 24:00 twice this fall. I just ran a rust-buster 3k last week
with no speed-work in 8:07, my best in college was 8:24. If you had
told me back then I could improve this much running 4 days a week I
would have laughed in your face, but I've found consistent aerobic work
is by far the most important factor in running well. Biking appears to
be almost as effective as running for this steady base. So what I'm
saying is, if I can completely replace running days with biking, then a
bit of extra low resistance biking can only help you. I'd love to see
more people try it. I know there are a ton of people out there like me
who just butt there head against the wall over and over again trying to
fit the training mold for the typically runner. The fact is we are all
very different and can handle different amounts of the shock that comes
with running. By supplementing biking I believe you are far less
likely to get injured and putting in months and months of 80 mile weeks
with extra biking is much better than a few hundred mile weeks in a row
with periodic interruptions. Anyway sorry for the long winded answer,
but I hope it helps. Let me know if you have success with it this
year. I'd like to write more about this training approach sometime,
especially if I'm able to drop another 5 or 6 seconds off my 1500.
Good luck