low back pain

I've encountered the same problem. I have chronic low back pain, but
with proper therapy and bike adjustments now I can ride 100-plus miles
to train with little aching, but in a race the pain gets really bad
starting at 20 miles.
My theory is that I tense up during the race. I find myself NOT getting
in the right position on the bike, pushing a little harder, and really
tensing up muscles all over.
I first noticed it in regards to the swim: I'd get out of the water and
my legs would feel dead tired, but I don't kick at all when wearing a
wet suit... then I noticed I was tensing my muscles like I was holding
onto a pool buoy.
Same on the bike, I feel myself tense up all over, and then the aching
comes on at about 20 miles.

I've tried to make myself relax with minor success, even spent a couple
minutes sitting in the transition area to calm down before mounting the
bike. Maybe I need a massage and yoga break in the transition area?
Eric

Steve Shattuck said:

Riding 100+ miles is typically not a problem for me if I'm moving at a
leisurely pace, ie: 15 to 18 MPH.
When I am racing, once I go beyond a bout 20 miles I start getting some
pretty intense low back pain. This pace is usually 20+ mph. Not sure why
pushing causes the pain but it sure does. Any suggestions on how to solve
it. I'm in the Timberman next weekend and I'd sure like some hints prior to
the event.
Thanks to all.
Steve

Steve Shattuck said:

Riding 100+ miles is typically not a problem for me if I'm moving at a
leisurely pace, ie: 15 to 18 MPH.
When I am racing, once I go beyond a bout 20 miles I start getting some
pretty intense low back pain. This pace is usually 20+ mph. Not sure why
pushing causes the pain but it sure does. Any suggestions on how to solve
it. I'm in the Timberman next weekend and I'd sure like some hints prior to
the event.
Thanks to all.
Steve

I get the same problem. Unfortunately the solution for me was lots of
lower back and ab flexibility and strengthening work, plus doing more
training at race pace. Not going to help you much for next weekend I'm
afraid although obviously warming up and stretching up properly will
help.