By Mike Steck
One question that frequently comes up in the fitness world is of the role the lats play in the bench press exercise. There does not seem to be a clear-cut consensus among fitness professionals on this issue. Most would agree that the lats are stabilizers, critical to the execution of a solid lift. But many claim the lats directly contribute to the upward pressing of the barbell. Given that they are widely known for their role in pulling exercises – such as rows, pull-ups and pulldowns – one might ask how the lats can help you push a barbell upward. This is a valid question, but the answer is not quite so clear. As we will see, when pull comes to push, there is more going on than meets the eye.
So, do the lats directly contribute to the upward pressing of the barbell during the bench press, or are they simply stabilizers forming a solid foundation from which to generate force? Although I won't claim to have the definitive answer, I will explore how the lats work, specifically the various places they attach and the movements they contribute to. I will also examine research on activation of the lats during the bench press as well as seek the thoughts of other professionals in the field. I will then leave it up to readers to draw their own conclusions.
To understand the function of the lats, it is necessary to locate their various attachment sites. The proximal attachments (i.e., origin) of the latissimus dorsi muscle are the spinous processes of T7-T12 and L1-L5, the thoracolumbar fascia, posterior sacrum and iliac crest, and the bottom portion of the ribcage. It's insertion is at the bicipital groove of the humerus. This location is interesting considering the lats are commonly thought of exclusively as part of the back musculature; the bicipital groove is on the front of the humerus. This attachment site, as I will discuss shortly, allows the lats to contribute to movements that they are not commonly thought to contribute to by those not well-versed in anatomy. See the images below for a better understanding of these attachment sites.
To understand the role the lats play in the bench press, we need to look closely at just what exactly the lats do. I'll start with their basic function. The lats assist in depression, downward rotation, and retraction of the scapula. Their attachment at the front of the humerus allows them to contribute to various movements at the shoulder joint, including extension, adduction, and medial (internal) rotation of the arm. This last movement is where things get interesting, but in order to see why, it is important to understand how muscles work on an individual level. A muscle produces what is called tensile force, which can be defined as a pulling force. Thus, when a muscle contracts, it is pulling toward its center, bringing the insertion toward the origin. That being said, what makes medial rotation of the arm by the lats so interesting?
Let's consider the bench press as the average (and properly coached) lifter would execute it. It is generally recommended that at the bottom of the movement, with the bar touching or nearly touching the lower chest and the hands placed just outside shoulder width, the elbows are at roughly a 45 degree angle to the torso. In this position, the upper arms are adducted and externally rotated, and the shoulder is transversely extended (elbows behind the body). Now, what's interesting is that the insertion point of the lats is now behind the torso and, therefore, slightly away from the origin. So, if one consciously (and correctly) engages the lats in this position, they will medially rotate the arms, flaring the elbows slightly and bringing the humerus more level with the torso, seemingly initiating the upward movement of the barbell.
But how much can this slight movement initiated by the lats contribute to the upward drive of the barbell? In a 1995 study done by Barnett, Kippers and Turner, EMG activity for five different muscles were analyzed during the bench press done at varying angles and hand spacings. The study found activity of the lats to be “very low under all conditions” with “a short burst of activity just prior to the start of the lift.”* This appears to support what I discussed in the previous paragraph, but it also seems to indicate that the lats do little to generate force in the bench press. Nonetheless, some insist that the lats have a larger role to play.
According to Tim Henriques, director of the National Personal Training Institute of Virginia and author of the book All About Powerlifting, “The lats literally contribute by helping you driving the bar off the chest...” but, “Their contribution decreases as you continue to press the bar away from you.” However, he adds, “the lats aren't completely finished helping you even after the first few inches of the press. Another key function of the lats is to produce internal rotation... Most good lifters know to flare your elbows out as you press the bar up after the initial press on the bench. This flare will create some internal rotation which helps activate the lats among other muscles...” So Henriques believes that the short burst of activity in the lats at the bottom of the movement is significant, but seems to concur that once the bar heads upward activity in the lats diminishes. Yet, he still insists they have a key role to play during the ascent phase of the lift. But again, not everyone agrees. According to Justin Lascek, a strength and conditioning coach, writer, and editor for 70sBig.com, “... internal rotation when benching or pressing isn't caused by the lats, but it's an error made by the lifter that often results in injuries. Instead, the shoulder should be in some degree of external rotation when benching...” Obviously, this matter is open to question.
So what can we agree on?
“When you're talking about the drive or force production of the bar the chest is obviously the prime mover and not the lats, but when talking about stability the lats do play a major role and without proper stability there, your press will not be as effective. Proper stability precedes good strength,” says Steve Cook, a Los Angeles-based strength and conditioning trainer and owner of Primal, Inc., when asked about this issue. Here Cook sums up what it seems few would debate. Although the lats are not generally considered an agonist muscle during the bench press, they are widely regarded as a stabilizer, and the importance of stability can be see when observing any gym newcomer learning the bench press. Often, their movement will be very loose and uneven. Their press will be crooked and the bar will drift from side to side. But after proper coaching on how to create tension (i.e. stability) in the body – chest proud, shoulder blades pinched, abdominals braced, glutes squeezed together – their press will straighten out substantially. And at the bottom of the movement, especially, the lats become a key player in maintaining that tension, the critical foundation of the lift.
When any movement is executed correctly, engaging the muscles in just the right way, there is a remarkable symmetry of motion. In a sense, every exercise is a full-body exercise, because no muscle ever acts alone. The body always works as a system, and a very complex and amazing one at that. When muscles are engaged properly to move the body in a certain way – in this case, pressing a barbell upward from a lying position and barring any individual physical limitations – everything is in place to facilitate effective force production with minimal risk of injury. So in addition to aiding stability, perhaps that short burst of activity just before pressing the bar upward puts the elbows at just the right angle to execute a clean, solid bench press. Perhaps it does that and then some. Or perhaps more research is needed to obtain the definitive answer. Until then, I leave it to you to decide what you think.
* Italics added.
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