Front Or Rear Lats Pull-down ?

The pull-down is a staple lat exercise, especially for anyone not yet strong enough to do pull-ups. For years, though, many fitness writers and personal trainers have cautioned against bringing the bar down behind the neck, urging lifters to bring it down to the front instead. They argue that behind-the-neck pull-downs aren't as effective as front pull-downs and may even lead to injury.So why is it that you can walk into practically any gym and see someone doing behind-the-head lat pulls? Some people like this variation because it places a different angle of emphasis on the traps, which they believe will lead to better results. Still others are actually using it as a trap exercise—which makes no sense, because there are plenty of trap-specific exercises out there that work better.

THE RIGHT MOVE FOr MUSCLE ACTIVATION

The hand positions used were close grip, supinated (underhand) grip, wide-grip in front of the neck, and wide-grip behind the neck.It is concluded that the lat pull-down exercise with wide-grip hand position brought to the front of neck produced greater muscle activity in the latissimus dorsi than any of the other hand positions studied. This finding supports the use of lat pull-downs to the front to maximize muscle activation of the lats.Another study,  evaluated EMG activity of some of the main muscles (pec major, lats, posterior deltoid, and biceps) used during three variations of the lat pull-down.2 The exercise variations were behind the neck, front of the neck, and V-bar (close grip).Although no differences in muscle activity of the lats were observed using the different variations, muscle activity of the pec major was highest with the front-of-the-neck variation. Furthermore, the posterior delt and biceps brachii demonstrated higher activity during the behind-the-neck variation. Considering the main objectives of the exercise, the authors singled out the lat pull-down to the front as the better choice.

STRESS ON THE SHOULDER JOINT AND ROTATOR CUFFS

But muscle activation isn't the only consideration when evaluating the lat pull-down; stress on the shoulder joint is an important factor as well. According to a studies, when the shoulder joint is placed in a position of horizontal abduction combined with external rotation (as seen with behind-the-neck lat pull downs), more stress is placed on the rotator cuff in order to stabilize the head of the humerus.3 This forces the rotator-cuff muscles to work harder to stabilize the joint, making them vulnerable to injuries such as tendinosis and pain.

So Its clear that real winner is front version of the exercise, DO it and remain injury free in long run.