I thought I'd leave the report a few days, just to see how it all worked out, and it looks like I'm OK (not too much numbness in any foot), so it looks like some running might be possible for me, after all.
On Saturday I went to our North Beach parkrun with intentions of running part of the way, and very slowly. I did this barefoot. The idea was just to continue probing how much running I can do without aggravating my back problem.
The reason for running barefoot is that the reading I've done online suggests that there is significantly less peak force (impulse is the proper term, I think), running barefoot vs running shod. Actually it's more to do with forefoot strike than barefoot running, but if you land at all roughly barefoot, you immediately know it, and correct automatically. Here's the link:
barefootrunning.fas.harvard...
The run was quite hard, because it's been so long since I last ran for any distance. (I sometimes jog slowly up hills on my walks these days, but that doesn't last long). I also sprang a leak in the right tyre (or, more prosaically, stubbed my toe). Because of my concern with my back the stubbed toe didn't worry me as much as it otherwise would have. My mind was on other things. To avoid wearing out the soft soles of my feet I took a few detours. There's grass in front of the lifesavers building we pass early on, so I diverted to that. I also ran down onto the sand near the halway point (but not on the way back; it's heavy going all the way down to the firmer sand washed by the waves; and even heavier going, going back to join the promenade).
At halfway, I paused briefly to hear what the time was, and then headed back mainly over the paving. Looks like the spinning has preserved my aerobic fitness nicely, so I must be setting my effort level sufficiently high, because at no point did I really need a break, I just eventually walked the paved bits, because of the stubbed toe.
My time was 39:something, which I was quite pleased with, all things considered. I should not have been pleased, because my deal with myself was that I would go Really, Really slowly, just to play it safe, and that time is a bit fast when the detours and walk breaks are taken into consideration. Anyway, no harm done.
And then there are the after effects. Ow! I've spent Sunday being really stiff, and this morning I'm still not yet properly mobile. You keep your fitness if you keep training, but a lot of muscles start to lose condition. Run, and they work a bit too hard. It didn't help that we had quite a long queuing time in the scanning funnels, I think. Cool down saves you quite a lot of pain. If I do this again next week I think I'll first go for a cool off, and then come back to be scanned. There's no urgency in getting your card scanned, after all.
So the conclusions?
Well first thing, I'll restate the most basic rules: If you get numb feet, stop what you're doing, and attend to them. It's not going to just get better. And before that rule, I would be inclined to say "Tendons first". Before getting carried away with developing muscle, give the connective tissues a chance to develop.
If you do end up with a herniated disc, it's possible to run without too much harm - possibly. It certainly feels OK, having done this. Moderation would be the rule for that, assuming that I'm not being a fool pushing this. If it turns out that this works, see "rule one": Before all else, look after the back injury the numb foot is announcing to you. Be active but very careful, and if experiments with running start to come unstuck, bail out. Don't commit to stupidity. (Actually "Don't commit to stupidity" isn't a bad rule for many things).
I think also that to whatever extent rehabilitation is possible (and the prospects for compressed discs recovering are meant to be pretty hopeless) in order to initiate any repair you need to do a tiny bit of "damage". If you completely avoid all impacts, your discs are simply going to adapt themselves to an impact free world (become weaker). To become impact resistant, you need to subject your body to impacts. I'm pretty sure that has to be right. In a way, you just need to apply the same moderation you need to apply to make a sound start to exercise after a long spell on the couch. In this case, though, the "tendon" that comes first is an intervertebral disc - a finicky thing.
Hmm ... I suppose I can claim an actual Week 8 Run 1 here, too. I'm pretty sure I did at least 28 minutes continuously. Here's hoping there are no unpleasant surprises as a consequence in the week ahead.