Sport-Specific Loading Drives Ultrasound-Detected Entheseal Adaptations in Elite Athletes

Background: Entheses are load-bearing interfaces highly responsive to repetitive mechanical stress. In elite athletes, sport-specific loading patterns may induce adaptive remodeling or microdamage at tendon-bone junctions. Ultrasound (US) enables early detection of such changes, but systematic comparisons across different sports remain limited. Methods: In this cross-sectional study, 87 elite athletes (athletics, basketball, cycling, golf, handball, climbing, archery) and 49 sedentary controls underwent US evaluation of 20 bilateral entheseal sites, resulting in a total of 2720 entheseal assessments. Athletes were classified as upper- or lower-extremity dominant based on sport type. Inflammation (hypoechogenicity, thickening, power Doppler) and damage (erosions, enthesophytes, calcifications) features were scored semiquantitatively (0–3). Group comparisons were performed with Mann–Whitney U and regression analyses. Results: Athletes demonstrated significantly higher inflammation and damage scores compared with sedentary controls, with distinct patterns according to sport and extremity dominance. Upper-extremity dominant sports (archery, handball, climbing, basketball, golf) showed elevated upper limb scores, while lower-extremity dominant sports (athletics, cycling, climbing, basketball, handball) exhibited increased lower limb scores. Climbers demonstrated the greatest overall entheseal burden. Despite marked imaging abnormalities, many athletes were asymptomatic. Conclusions: Sport-specific mechanical loading drives distinct entheseal adaptations and microdamage detectable by US in elite athletes. These subclinical findings highlight the need to contextualize imaging results within sport-related loading patterns and may support load management and injury prevention strategies.