Went on my first outdoor workout ride of the year and developed some lower back numbness and want to figure out why. The numbness is located just above and towards the spine from the posterior iliac spine of the hip (right around where back dimples are). The feeling is very shallow and includes the skin being numb. It has occured before with longer sustained efforts outdoors but never during a TR session. I haven’t been a consistent rider in years and while I’ve only done LV SSB and the first part of SPB I think my leg and aerobic gains are out pacing my untrained core.