Yep -- I get that "back screaming" feeling, and it just about does me in. I try stretching on the bike, standing on the pedals, stretching out horizontally over the back of the seat, side twists to each side, etc.
I often get off the bike for a few minutes and do some stretching using my bike as a prop. The screaming muscle is generally going to be a spasm and if the muscle is warm from riding, you can stretch it out and get going again. Believe it or not, I also find it helps to put on more gear and slow down my cadence. Make sure you are not rocking your hips -- an indication your seat may be too high.
I had the screaming back yesterday about 15 miles from the car
. I employed every one of these tricks for about 4-5 miles and was able to ride the last 10 miles pain free.
I will be at the chiropractor twice this week... I'm sending one of his kids to college with my regular visits.
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