Trap Function 101
Besides looking weird on an averagely developed build, humongous traps won’t do much for your athletic performance. This doesn’t mean that they don’t serve a purpose though. Here’s a quick lesson in anatomy to help you understand trap function better.
According to most definitions, the trapezius muscles are large, diamond-shaped surface muscles that extend longitudinally from the occipital bone to the lower thoracic vertebrae and laterally to the spine of the scapula. Because you see the traps mainly from the front, you probably think they merely sit atop the shoulders while in reality the traps travel down the back, which is how they get their diamond shape.
The traps are postural and active-movement muscles with a solid list of functions in the body. In short, they are responsible for moving the scapulae (shoulder blades) and supporting the arm. In greater detail, they are used to elevate, depress, rotate and retract the scapula, tilt and turn the neck, stabilize the shoulders, twist and support the arms and even assist in breathing. Having strong traps is very important for shoulder mobility and injury-free back training.
In general, the trapezius muscle is described as divided into three regions:
- the superior or upper region, consisting of the upper fibers
- the intermediate or middle region, consisting of the middle fibers
- the inferior or lower region, consisting of the lower fibers
The upper traps make up the biggest part of the muscles’ mass, are primarily responsible for lifting and rotating your shoulder blades upward, as when shrugging your shoulders. The middle traps have the job of pulling the shoulder blades together (think wide-grip seated rows), while the lower traps are here to rotate the shoulder blades downward, for example during the overhead portion of front raises.
However, these definitions are way too simplistic and merely serve a descriptive purpose, because in reality no muscle works in isolation – each muscle or group of muscle fibers works in synergy with others, functioning as one big unit at all times, even though some parts may be working harder than others during different movements.
That being said, the role of any given muscle in terms of movement depends not only on its insertion and origins, but also its orientation and the angle of its muscle fibers. Now, according to research, because of the angle and orientation of the upper fibers of the trapezius muscle, it is almost impossible for this muscle to produce any significant elevation of the shoulder blades when the arm is in a neutral position.
In fact, the upper fibers need the coordinated assistance of the middle and lower fibers in order to elevate the scapula, but even then, they can’t do the job without coordinating their work with the work of the serratus anterior muscle which covers the side of your rib cage. So again, just like any other muscle, your traps can’t work in isolation. If this is so, how can you expect to effectively build your traps by merely doing direct isolation movements that fail to optimally engage these strong muscles?
When you’re stuck on only using shrugs, which incorporate only elevation/upward rotation of the scapulae, you’re leaving a ton of potential resources untapped and opting for incomplete muscle development. So if you’ve already decided to build huge traps, you should at least learn how to do it the right way instead of slaving at the gym for hours with nothing to show for it.
Continues on next page (Best Exercises for Traps) …