Eric D'Agati, founder of One Human Performance and Co-Creator of 'Principles of Program Design,' discusses mistakes in program design, getting buy-in and rapport, and developing a system. Coach Boyle shares insights on little league shoulder and foam rolling research. Vince Gabriele talks about how many hours gym owners should spend on marketing. The importance of pain-free strength training in children, enhancing Instagram engagement, and embracing feedback are also discussed.