A pull-up is an upper body compound pulling exercise where the body is suspended by extended arms, then pulled up until the elbows are bent and the head is higher than the hands, utilizing an overhand (pronated) grip. A traditional pull-up relies on upper body strength and swinging or "kipping" (using a forceful initial movement of the legs in order to gain momentum) making the exercise a power and conditioning movement as opposed to a pure strength one. The exercise targets mainly the Latissimus Dorsi muscle in the back along with many other assisting muscles. Pull-ups are similar to chin-ups, which are distinct due to the underhand (supinated) grip.
Muscles utilized Edit
Pull-ups primarily target the Latissimus Dorsi muscle group in the back, though many other muscles are involved in the movement. These assisting muscles include the Brachialis, Brachioradialis, Biceps Brachii, Teres Major, Deltoid muscle, Infraspinatus, Teres Minor, Rhomboids, Levator Scapulae, Trapezius Lower, Trapezius Middle, and Pectoralis Minor. 
Since multiple joints are utilized, pull-ups are known as a compound exercise.
List of variationsEdit
|A standard pull-up||
Standard dead-hang pull up is grasped with an overhand grip. Then the body is pulled up until the chin clears the bar, and finished by lowering the body until arms and shoulders are fully extended. Stricter standards would only consider a full repetition to be one in which the elbows pass behind the coronal plane.
|Animation of a weighted pull-up||
Weight is added using a dipping belt, or grasping a dumbbell with the feet.
|Animation of a behind-the-neck pull-up||
The chin is dropped the goal of the pull-up is to touch the bar with the back of the neck.
|Animation of a one arm pull-up||
One arm pull-up
A one arm pull-up is performed by grasping the bar with only one hand while pulling up. Due to its difficulty, it requires considerable fitness.
|Animation of a muscle-up||
The muscle-up is performed by pulling up, but rather than stopping with the chin or chest touching the bar, the arms are straightened, raising the body above the bar. Generally the initial pull-up uses an overhand grip to make the switch easier and is more explosive in order to use the momentum to make the exercise easier.
Sometimes called a "Reverse Push-up", this is performed with the bar 2 to 3 feet off the floor. The user lies on the ground under the bar, face-up, and grasps the bar with extended arms. The exercise is performed by pulling the chest up to the bar. The body is held in a rigid plank position while the heels remain on the floor.
Mixed Grip Pull-up
One hand is placed in the overhand (pronated) position and the other is placed in the underhand (supinated) position to provide variation on the standard pull-up (and chinup).
Videos of various Pull-up Combinations from StudBarPullup.com http://www.youtube.com/watch?v=AGOiZ24Yrxc