From Ergo Log
The five faithful readers of this web magazine already know that you’ll get more out of your lat pulldowns by pulling the bar to your chest rather than the back of your neck. If you want to perfect your technique even further, you’ll be interested in the results of research done by sports scientists at Pennsylvania State University, published in the Journal of Strength and Conditioning Research.
In their study the researchers worked out what the best grip is to use for lat pulldowns. Does it matter whether you hold your hands far apart or close together? And does it matter whether you grip the bar from above [palms facing away from you] or from below [your palms turned towards your face]?
Not really necessary, but for the sake of completeness, in the photo here the guy is gripping the bar from above with his left hand and from below with his right hand.
The researchers got 12 men aged between 19 and 30, all of whom did weight training in their leisure time, to do lat pulldowns at 70 percent of the weight at which they could manage just 1 rep. The researchers attached electrodes to the subjects’ biceps [BB], the broad upper back muscle [LD] and the middle part of the trapezius [MT]. This enabled them to measure how intensively the men were using these muscles.
The researchers then studied 4 different ways of doing lat pulldowns: hands wide apart and gripping from above [WP], hands far apart and gripping from below [WS], hands close together and gripping from above [NP] and hands close together and gripping from below [NS]. The only statistically significant effect was on the latissimus dorsi, the broad upper back muscle, as you can see below: the figure shows the effect of the different grips on the activation of this muscle group.
Pronation = grip from above, downward facing palms; supination = grip from below, upward facing palms.
As you can see, it makes no difference whether you grip the bar with your hands wide apart or close together. Instructors swear that you should keep your hands wide apart, because if you hold them close together you use your biceps more than your back muscles, but that guideline will no doubt change soon.
What does make a difference is how you grip the bar. If you grip it with your palms facing downwards, you’re doing it right.
J Strength Cond Res. 2010 Jul; 24(7): 1895-900.