No matter how much time I spent stretching my biceps after the gym I could never manage to prevent stiffness/soreness appearing the next day. Well, after doing day 3 fundamentals I now know its because I was actually doing wrist stretches when I thought I was doing bicep 
The moment I went into the crap position I felt that much needed bicep stretch that I was never able to achieve, it felt soooooooooo good!
Only 3 days in and I'm loving this course already.....