http://youtu.be/UMC48BO-GQE
He pulls down the bar well. Notice how much he arches his back, broadens the front of his chest, keeps his shoulders down and his elbows under his hands. When his arms are straight, the shoulders rise and the back relaxes.
By all means pull the bar down to the top of the chest BUT do check that your chest stays broad and shoulders down. He doesn’t mention 2 other common mistakes in the Lat Pull Down. The first is that the shoulders lift as the bar is pulled down. This is generally caused by lack of knowledge or not thinking about what is trying to be achieved, ie a back workout. In the picture below, the lats are muscle D. They run from the very top of the arm down into the grey bit seen in the picture, attaching onto the spine from the middle of the upper back and down to the hips. In other words, the lats attach your arms to your bottom. Other muscles that engage are B and the middle and lower parts of A
The second mistake is that as the bar goes down to the chest, the fronts of the shoulders tend to roll forwards and down.
This is caused by a lack of ability to bend the upper back backwards enough and by a muscle called the pec minor being short and tight and holding the shoulders forwards and down. You can see the muscle marked in red.
As he says, if you don’t broaden the chest sufficiently you are working inefficiently. It would be better to pull the bar down only as low as the body will allow whilst the problems causing the poor movement as the bar reaches the chest are sorted out.
You can hold the bar in many positions as well as the wide grip demonstrated. The wide grip hits those back muscles most whereas holding the bar shoulder width apart with palms facing you will use more of the biceps. In all exercises, it is important to vary grips, angle and tempo for the best effect.
Because the body is fixed, the transition from a lat pull down to a chin up will always be big. A well performed chin up involves the body actually slightly rotating around the bar. This little clip of a superbly performed pull up demonstrates this:
Crikey, he’s tireless!
The difference between a chin up and a pull up is hand position – palms away, as above, is a pull up, palms facing you is a chin up.