First of all, thank you for existing... I only wish I knew about this decades ago!
I'm a 37yrs old soldier with (surprise, surprise) tight shoulders, back, hamstrings etc... Did my 1st Core today, and found I had trouble with the Stiff Leg Windmill. The biggest issue was attempting to keep the arm straight up (shoulder was ultra tight and fought me the whole way), and noticed hamstring resistance as well...
My question: Is there anything I could do to improve on this, some sort of stretch prior to, a different move to progress to this or anything else?