2) Muscular calfs with a defined muscle.
It comes from the term kancles where the calf hangs over the foot. In this occurrence the calf is on the calf generally not referring to the obese but to runners.
Sentence: Look, that hurdler has calffuls.
2) When I do track we run a lot and our calfs get stronger and defined. This then causes us to get muscular calfs resulting in calffuls
Sentence: Did you see that runner's calffuls?