starting Piyo with my running

I said in my last post my goal is to be a fit mom and add strength to my runs.  This morning had to be a fast run (I tried to sneak out the door by myself but my daughter woke up).  I got in a 2 mile run with sub 10 minute miles for the first time since I got pregnant.  And then this afternoon I did the first workout from the Piyo workout series by Beachbody.  This workout was just the fundamentals so I know what I am doing in the other workouts...and I feel it in muscles that I never remember to stretch!  Doing the double workouts a day could go one of two ways...I become a stronger runner with more flexibility or 2 - I am no longer able to move.  I am really hoping it's 1 and I become a stronger runner adding flexibility and strength.  We will see what the next few days bring and how I am able to fit the workouts along with my daily routine in.