Small “delicate” frame and bone structure 

Classic “hard gainer”

Flat chest

Small shoulders

Thin

Lean muscle mass

Finds it hard to gain weight

Fast metabolism

Athletic

Generally hard body

Well defined muscles

Rectangular shaped body

Strong

Gains muscle easily

Gains fat more easily than Ectomorphs

Soft and round body

Gains muscle and fat very easily

Is generally short

"Stocky" build

Round physique

Finds it hard to lose fat

Slow metabolism

Muscles not so well defined