What Muscles Are Hardest To Build?

What Muscles Are Hardest To Build? Obliques. Pretty much everyone does the standard ab crunches, but crunches aren’t going to develop your obliques. … Calves. … Forearms. … Triceps. … Lower stomach. What muscle is hardest to grow? Calves. Calf muscles are also considered as one of the most difficult to grow in the gym,