When gym go-ers think of their "traps" (known as trapezius in the anatomical world), their mind automatically begins to think of the shrug.
The problem is, performing shrugs only works the part of your trapezius highlighted in yellow, your upper trap.
It's true that having a strong trapezius will benefit you in your lifting, but when you're missing 2/3 of the muscle it will only lead to postural abnormalities. Training this way, will hurt your lifting.
Here's why: the trapezius works in controlling your shoulder blade. When your arms move, your shoulder blades move with it to keep the shoulder aligned properly in the joint. For every 2 degrees of movement we see in the arm, there's 1 degree of movement of the scapula (shoulder blade.)
When part of the trapezius is stronger than the rest of it, it alters the movement of the scapula, taking the shoulder out of proper alignment. Specifically, when the upper trap is more developed than the rest of it, it pulls the shoulder blades up and your head forward. Bad joint motion is bad news.
We can determine what way the parts of trapezius move the shoulder blades by looking in the direction of the muscle fibers. Think of these fibers as string pulling the shoulder blades in the direction they're running.
If you're more anatomically advanced, we can think of the distal point of attachment moving towards the proximal. (Shoulder blade moving towards respective regions of the cervical and thoracic spine).
ACTIONS OF THE SCAPULA/SHOULDER BLADE
ACTIONS OF TRAPEZIUS AND EXERCISE EXAMPLES
Scapular elevation and stabilization of the scapula under carrying motion.
Scapular elevation: this is the motion you're doing during a shrug. You're elevating your scapula up towards your head.
Stabilization of the Scapula: Think of farmer's carries, deadlifts, etc. While holding the weight, your shoulders don't sag/pull down. Your upper trap contracts, and holds your shoulders up. In my opinion, this is the optimal way to train your upper trap.
Can you do shrugs? Sure! Do you need to? Not at all. Pick up a pair of dumbbells, a trap deadlift bar, or kettlebells, and take a 50m walk with good posture. As soon as your posture or grip starts to give, put down the weights and recover.
Scapular retraction: this motion is pinching your shoulder blades together
This should be done in so many lifts. With every row and pull up you should actively bring your shoulder blades down and back at the end of each rep. With every deadlift your shoulder blades should be held down and back the entire time. With every bench press your shoulder blades should be held down and back the entire time. With every farmer's carry, with so many exercises. It's good posture! Good posture should never be sacrificed for extra weight.
Seated Scapular Rows: Here you're seated at a row machine, instead of bringing your arms back into the row, lighten up the weight and just focus on bringing your shoulder blades together.
Cable Wrap Around Row: Similar to a reverse fly, but here you bend your arm at the elbow joint to shorten the lever arm. When pulling back, think about wrapping your shoulder blade back towards the opposite one.
Rack Pulls: This one's my favorite. Instead of hiking up the weight on a rack pull, go light! Set up so that your shoulder blades are already pulled together. Now maintain that throughout the whole lift. If your shoulders are falling forward, lighten up the weight.
Depression of the scapula, stabilization of scapula against thoracic cage.
Your lower trapezius is going to help hold your shoulder blades down. This is so important when performing pull ups. At the bottom of a pull up, never let your shoulder blades give in and let them shrug up towards the bar. Think about pulling them down and back. Just because the rep is over, doesn't mean the set