severity grade: 3
No idea of cause other than possible cumulative fatigue from tri on weekend, Monday's easy training and then hard ride Tues AM. I normally get a tight lower right back after about an hour of riding on one side, which I had Tues AM from about the 15min mark. On the way home easy pedalling I felt a 'bit uncomfortable' but didn't feel serious. Went to get off the bike and gasped with pain. Couldn't stand straight, unable to reach floor, put socks on etc. Fine lying flat or seated, painful strong ache standing. Unable to walk normally all day. Still sore Wednesday all day, mild improvement, hard to get out/in to chair at work. No shooting pains just spasmed low-mid back and strong ache.
Lumbar spine 'hinges' instead of curves at L2/L3. Theory is hard ride Tues over loaded the hinge point and there was a minor shift of one of the joints and concurrent severe muscle spasm.