Muscle Endurance:  Being able to use your muscles  
for a long period of time. 

Muscle Strength:  How strong your muscles are at  
different events. 

Flexibility:  Keeping your muscles stretched to stop  
from getting hurt. 

Aerobic Endurance:  Being able to exercise for long  
periods of time without running out of breath. 

Body Composition:  How much muscle you have compared  
to how much fat you have. 

Aerobic Exercise:  Aerobic exercise helps make the heart and lungs  
stronger by increasing the oxygen available to the body and by enabling  
the heart to use oxygen better.  It uses the same large muscle group, rhythmically,  
for a period of 15 to 20 minutes or longer while maintaining 60-80% of  
your maximum heart rate.  Aerobic activities include: walking, biking,  
jogging, swimming, aerobic classes and cross-country skiing.

Anaerobic Exercise:  Anaerobic activity is short in time but high in effort.  
Anaerobic activities include: racquetball, downhill skiing, weight lifting,  
sprinting, softball, soccer, and football.

Ectomorph:  This body type is characterized by a light  
build and slight muscular development. Ectomorphs 
may even have trouble gaining weight and feel they are too thin.  
As with other body types, people who fall into this category should exercise,  
but will have a different focus. Because they are often trying to gain weight,  
an ectomorph might spend more time on  
strength training and a bit less time on cardio work. (1) 

Endomorph:  This body type is characterized by a stocky  
build, wide hips, and the annoying tendency to easily store  
body fat. Endomorphs may also have more internal fat around  
the organs, which makes fat loss more difficult than other  
body types. People with this body type will want to pay  
close attention to their diets and make sure to follow a  
complete exercise program that includes cardio and  
strength training. (2) 

Mesomorph:  This body type tends to be more muscular, with  
a large chest and a long torso. A person with this body type  
may find it a little easier to build muscle than others.  (3) 

(1) By Paige Waehner, About.com  
(2) By Paige Waehner, About.com  
(3) By Paige Waehner, About.com