The influence of this program has its roots in three different places. Firstly, we have all likely heard of or completed the Hatch Squat cycle. This program has the lifter performing both Back Squats and Front Squats in the same session. I love that cycle and my legs respond extremely well to performing both squats back to back. I was always playing with ways to make that happen in different ways.
The second influence came from one of my coaches, Richard Flemming, has always loved making his athletes perform front squats followed by back squats at specific times during his program. So his influence was HUGE.
The last influence came from the love/hate relationship I have with 20 rep back squat programs. I love the size they develop in my legs but hate the process. However, I loved the 20 rep idea. Hence 7+13=20 reps.
Enjoy the program!