So, Tuesday AM I went out for about a 5 mile BF run through my asphalt neighborhood.  Felt really good, too - no problems.  Then, nearing the end of the run I decided to see how it would feel to run fairly fast - did 4 or 5 fifty meter sprint/jogs with no apparent  problem.  But after I got home I realized I had bruised the bottoms of both feet, I guess from the extra force of running faster than my usual BF jog.  Too much too soon!  They are still sore as heck today and I might take tomorrow off too.  Ugh!!!!  Be careful out there! 

MTA:  So I think the way I'll handle this is to start with 1 stride each time and build slowly from there...