Which exercises work the upper, middle and lower traps?

Where are your traps?

Your two traps form one big diamond, from the back of your skull down to the middle of your back. On the sides, they attach to your clavicle and your scapula, your shoulder blade. Each one has three parts: the upper, the middle and the lower.

In dissections, the fibers from the back of the skull and the neck run to the clavicle; those from the base of the neck, almost horizontal, to the acromion and the spine of the scapula; those from the back converge on the spine of the scapula. The thickest start at the base of the neck (Johnson et al., 1994).

What do the traps do?

When you shrug, the upper part lifts your scapula by swiveling your clavicle: that’s elevation. For the authors of the dissection study, its almost horizontal fibers mostly pull the scapula and clavicle back, or lift the scapula through that rotation of the clavicle, rather than hoisting it straight up (Johnson et al., 1994).

The middle part, with the rhomboids hidden underneath, squeezes your shoulder blades together: that’s retraction. In 12 adults, measured with fine-wire electrodes, the middle traps and rhomboids worked together in all four positions tested (Fennell et al., 2016).

When your arm goes up, the traps rotate your scapula upward (Ekstrom et al., 2003). Arm all the way up, it had rotated 36° on average, in 21 healthy adults (Yano et al., 2010). That’s why your traps work on lateral raises: in 20 young men, upper, middle and lower trap activity rose as the arm moved out and up, with a plateau (Bagg and Forrest, 1986).

Which exercises for the upper, middle and lower traps?

For the upper part, on shrugs, spread your arms about 30°: your scapula rotates as well as lifts. In 23 adults without pain and 14 with an unstable shoulder, the upper and lower traps activated more than with the arms at the sides (Pizzari et al., 2014).

For the middle, squeeze your shoulder blades at the end of your row: it works there with your rhomboids, which are even slightly more active (Fennell et al., 2016).

For the lower part, Y raises lying on your stomach: out of 10 exercises tested in 30 adults, that’s where it activated the most (Ekstrom et al., 2003). Arms below shoulder height, side-lying external rotation and wall slides activated it about a third less than the Y, in 32 adults (Garcia et al., 2023). In 45 adults, side-lying external rotation and forward arm raise, horizontal abduction with external rotation and extension lying face down worked the lower and middle traps with little upper-trap activity (Cools et al., 2007). Pull-ups work the lower traps too, more with an overhand grip than with chin-ups, in 25 adults (Youdas et al., 2010).

Which exercise grows your traps the most?

Your traps do grow with lifting: upper-trap fiber cross-section grew 36% in ten weeks in 9 women (Kadi and Thornell, 2000); the upper traps thickened over ten weeks in 21 trained men (Bartolomei et al., 2021); the lower traps, by 0.3 mm after six weeks of shoulder-blade exercises in 19 office workers with shoulder pain (Go and Lee, 2016).

But the exercise comparisons above all measure how the traps activate: none compares which exercise grows them the most. They show where the traps work, not where they grow the most.