Greater weapon-side supraspinatus tendon thickness in elite national-team fencers: an exploratory cross-sectional ultrasound study

Fencing exposes the weapon arm to repetitive loading that differs from conventional overhead sports, yet shoulder morphology in elite fencers is poorly described. We compared supraspinatus tendon thickness, resting acromiohumeral distance (AHD), and occupation ratio between shoulders in 15 elite national-team fencers without current shoulder pain during daily life or competition. Bilateral ultrasonography measured tendon thickness at 5 and 10 mm lateral to the biceps tendon in the modified Crass position. Mean tendon thickness was greater on the weapon side (5.37 ± 0.89 vs 4.67 ± 0.96 mm; mean difference, 0.70 mm; 95% CI, 0.30 to 1.11; p = 0.002), with the difference most evident at 5 mm. No statistically significant between-side difference in resting AHD was detected (p = 0.085), whereas occupation ratio was higher on the weapon side (p = 0.013). Our findings suggest that fencers’ shoulders can differ in structure even when neither side is painful. This is worth remembering when the opposite shoulder is used as an ultrasound reference, although the cause and clinical relevance of the difference are not yet known.