I was an avid runner, marathons down to 5K when I was hit with UC, back in 2000...I have never returned to form. It seems for me that the bounding has an effect on urgency, my low back DDD is exacerbated from the arthritis conditions that come with UC, and general fatigue are working against me...I am somewhat defeated in this regard. I look with envy when I see someone out running...I still make attempts but am just not there yet...cycling is a nice alternative as there is no jarring of the body, unless you wipe-out
I raced cycles for a couple years after I contracted this wretched disease. Good luck to you!!
DB