To optimize shoulder work during dumbbell presses, it is recommended not to let the dumbbells touch at the top of the movement in order to avoid excessive recruitment of the trapezius and to maintain constant tension on the deltoids.

noli's read

This advice is based on a common biomechanical observation in the fitness industry: letting the dumbbells touch at the end of a vertical press often forces the shoulder blades to move forward (protraction) and upward (elevation), which can transfer part of the tension from the deltoids to the upper trapezius muscle. Biomechanics research supports that maintaining scapular stability (fixed shoulder blades) is crucial for isolating deltoid work. Although touching the dumbbells is not systematically dangerous, limiting it effectively helps maintain more localized tension on the shoulders, as suggested by hypertrophy-focused coaching practices. The idea that this reduces shoulder tension is valid in the sense that it avoids unnecessary compensatory movement. There is no meta-analysis precisely comparing "touching" versus "not touching" the dumbbells, but the empirical consensus favors a clean trajectory to optimize muscle recruitment.

the sources

No named source held this one up — that absence is part of the verdict.