Relationship of patellar tendon micromorphology with body anthropometrics and lower-limb range of motion in volleyball athletes

Abstract

Context Volleyball athletes frequently perform jump-landings, which can lead to structural changes in the patellar tendon. However, the relationship between intratendinous morphology, anthropometrics, and lower-limb range of motion (ROM) in athletes remains unclear, and the distal region of the patellar tendon is understudied. Objective To investigate the relationship between proximal and distal patellar tendon morphology with body anthropometrics and lower limb ROM in volleyball athletes. Participants A total of 132 elite-level volleyball athletes. Main outcome measure(s) Tendon thickness and intratendinous architecture (i.e., collagen organization, indexed using the peak spatial frequency radius, PSFR) were assessed with ultrasound at the proximal and distal patellar tendons. Anthropometrics included body mass, height, and waist-to-hip ratio. Lower limb ROM included ankle dorsiflexion (knee-to-wall), hip internal and external rotations, and hip extension (modified Thomas test). Single-leg squat was also tested. Results Athletes with patellar tendinopathy (51.5%) showed lower PSFR (1.59 ± 0.32 vs. 1.73 ± 0.31, p = 0.025) at the proximal tendon than athletes without patellar tendinopathy. Proximal tendon PSFR was negatively associated with years of play (p = 0.002). Distal tendon PSFR was positively associated with ankle dorsiflexion (p = 0.039) and hip internal rotation ROM (p = 0.031), and negatively associated with body weight (p = 0.008), body height (p = 0.030), and waist-to-hip ratio (p = 0.022). In athletes without tendinopathy, distal PSFR was also negatively associated with hip extension ROM (p < 0.05). Conclusions Proximal tendon PSFR decreased with more years of play, whereas lower distal tendon PSFR was associated with reduced ankle and hip ROM, greater body weight and height, and a higher waist-to-hip ratio, with small-to-medium effect sizes. Future studies should examine a broader range of biomechanical factors that influence regional tendon micromorphology.