Hi guys,
My two cents:
Back injury and deterioration can have multiple sources, and it's very true that other, non-cycling activities can aggravate the condition. My personal bugbear is jarring from too vertical a riding position, as Dan and others have described. However, I have also experienced pain (not injury, touch wood-grain screen on my iPad) from riding the drops on my Trek 520 that are now too low for me.
We humans beat the crap out of ourselves almost from the moment we can crawl. I spent yesterday playing with my beautiful and extremely energetic 18-month old granddaughter, and I marveled at the contortions, spills and bumps that little people can take. As we get older, we get shopworn and degraded. I've ridden (and fallen off) motorcycles for many years, broke my back in a car rollover, and have jammed my neck numerous times at work in mines. It's a wonder I can walk, let alone ride, but luckily, I feel pretty good for 62, all things considered.
Some of us gents also develop overhangs (guts) that no amount of riding seems able to shift, and the extra stress from having a boom bigger than your counterweight (
) doesn't do your back any good at all.
So, my advice:
1) Get your hand grip comfortable, no matter which angle is preferred. Do not use a death grip!
2) Adjust your bar reach and height so that you're generally sharing the load ( your weight) between your arms (slightly bent) and your bum. Your arms are by far your best shock absorbers, and more injuries happen from shock through the saddle than through your arms, as long as you keep them bent.
3) Try to prevent saddle jarring by posting, and by using a suspension, saddle and/or wide cushiony tyres.
4) Change positions from time to time, and take breaks at least every couple of hours.
5) Listen to your body. Pain is the way it tells you that damage is being done. Powering through back pain is not brave, it is foolhardy, as your back stops growing in your early 20s, and will not heal itself after that. That's why I don't trust pain and cortisone injections - they mask symptoms.
As has been pointed out, the good thing is that cycling can often relieve back pain, just as it can aggravate it. The main thing is to be aware of what you're feeling and what's causing it, and get good medical advice if you're not sure.
Thanks