Ultrasound Tissue Characterization (UTC) of the Achilles Tendon in Pre- and Post-Pubertal Dancers.

This study examined whether maturation status, body physique, and the impact of training are related to the development of Achilles tendon structure in young dancers. Seventy-one pre- and post-menarche dancers (12 to 15 years of age) were recruited. The Achilles tendon of each dancer was examined via ultrasonography tissue characterization (UTC) imaging. The cross-sectional area (CSA) and the fibrillar structure (echo types I to IV) were measured. The participants were screened for anthropometric parameters (weight, height, and leg length) with body mass index (BMI) and BMI percentile calculated; for hours and impact of training; for Tanner pubertal maturation; and for pain in their Achilles tendon (VAS scale). In addition, age and age at onset of menarche were documented. Tendon structure was found to differ between pre- and post-menarche dancers. Post-menarche dancers had a significantly lower percentage of echo type I fibers and a significantly higher percentage of echo type II, III, and IV fibers, with a greater CSA compared to pre-menarche dancers. The tendon structure was found to be correlated with BMI percentile, but no correlations were found with chronologic age or the impact of dance training. Furthermore, ANCOVA showed that BMI had a statistically significant effect on fiber types II and III (p < 0.005) and that the effect of menarche was significant, meaning that pre-menarche dancers had a lower BMI compared with those who were post-menarche. It is concluded that pre- and post-menarche dancers had developed different patterns of Achilles tendon fiber structure. Body mass index was found to be the most significant factor influencing the different tendon structures in young pubertal dancers.