Thanks for the info. It's interesting you should say low back issue, as it has been a little tight / sore of late as a result of some fairly heavy squatting. IMHO, there's no weakness there as I'm smashing PBs, but I guess this could cause problems that manifest at other times? If so, is it just a case of taking it easy for a bit / rest / stretching etc., or is there something more specific I should be doing?

As for the second point on connective tissue / referral, I'm not quite sure what you mean by that. How would I go about establishing if this is the case or even treating / preventing it?