I saw my ortho yesterday to review my MRI results. Great news! There is no sign of a stress fracture. There was some evidence of a bone bruise, but the MRI wasn't perfectly clear and it wasn't exactly where my pain had been. The doctor generally seemed unconcerned about it and felt the injury was likely muscular, which is what I thought all along and what I got confirmed by one of the coaches at my gym last night. "Oh yeah," she said, "We see that here. It's from jumping, like in double unders". Darn, where was that conversation 3 weeks ago before I wasted my time with multiple doctor's appointments and an MRI?
Bottom line is I've got the okay to start slowly reintroducing the "high impact" work. I've already been doing weighted squats so mainly this means box jumps and jumping rope. I'll admit I'm a bit terrified of setting myself back to square one, so I really will be taking it slowly, mostly leaving them out of my workouts and just doing an increasing number at home each day. I did do 35 box jumps in my workout today (on a very short softer box) and so far, so good!