Although traditional shrugs effectively target the upper trapezius, complete and balanced development of this muscle (which also includes the middle and lower portions) requires incorporating specific movements at varied angles, such as the Kelso shrug for the middle portion and the prone Y-raise for the lower portion.

noli's read

This anatomical approach is widely validated by research on muscle activation. A classic electromyography (EMG) study by Ekstrom et al. (2003, published in the JOSPT, an experimental study on healthy subjects) confirms that the traditional shrug is the best choice for isolating the upper portion, while the prone Y-raise is the gold standard for activating the lower portion. Other work, such as the cross-sectional EMG analysis by McCabe et al., confirms that it is essential to modify the pulling angle to effectively recruit the lower trapezius. The Kelso shrug on an incline bench allows for specific engagement of the middle portion by prioritizing pure scapular retraction. However, although this targeted approach is ideal for working on weak points or optimizing posture, suggesting that it is mandatory to isolate every area is a bit of an exaggeration. Indeed, many compound pulling movements (such as the deadlift or horizontal rows) already stimulate these three portions in a highly coordinated manner.

the sources

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