A one-word description for the ectomorph body type (or ecto, for short) is slim. If you're an ecto, mesomorphs and endomorphs usually don't want to stand next to you. It's not that ectomorphs aren't personable, it's just that you're probably a tall, slender individual who has trouble gaining weight (oh darn!). As you may have guessed, the perfect example of an ecto is a fashion model.
An ectomorph is relatively linear in shape with a delicate build, narrow hips and pelvis, and long arms and legs. As an ecto, your muscle and bone outlines are usually visible (especially if you are an extremely thin ecto), and you normally have less fat and muscle mass than people with other body types. Remember, though, that you probably don't have all the features of a characteristic endomorph, but a blend of features from more than one body type.
Your primary concern as an ectomorph is your frail stature consisting of small bones and joints that have a tendency to be injured easily during sporting activities. You probably won't be the star of your football team or the next champion gladiator. Don't worry — your body type is naturally suited to perform wonderfully in endurance activities. Just remember: Balancing your activities is the key. Like mesomorphs, ectos have a tendency to stick with what they do best, and ectos excel at cardiovascular training. You find balance in your workouts when you do both aerobic and muscle training.