Ultrasound imaging features of the Achilles tendon in dancers. Is there a correlation between the imaging and clinical findings? A cross-sectional study

To analyze the prevalence of tendon pathology and performance associated in pre-professional classic dancers with no history of Achilles tendon (AT) pain. Design: A cross-sectional study was conducted. Twenty-nine classic ballet dancers without AT pain (58 tendons) were recruited. The tendons were classified (normal, abnormal) using ultrasound imaging (USI). Cross-sectional area (CSA) and thickness of flexor hallucis longus (FHL) muscle were measured using USI. Range of movement (ROM) of the first metatarsophalangeal join, balance test, endurance test and vertical jump were measured (bilaterally) as performance variables. More than a half (62%) of the participants had at least one abnormal tendon, with 45% of the dancers in the abnormal group having bilateral abnormalities. Dancers with AT pathology had significantly more years of dancing and number of weekly pointe hours than those with no pathology on US imaging. No significant differences between the groups were identified for the rest of the variables. Dancing years were moderately correlated with AT thickness. Asymptomatic classic dancers had a high incidence of tendon pathology. Increased dancing years was associated with pathology in the AT. Nevertheless, these abnormalities may not affect dance performance. •Dancers are particularly susceptible to a wide variety of musculoskeletal injuries.•Ultrasound imaging is an important tool for the clinicians to control training load, and to prevent injuries.•Asymptomatic classic dancers had a high incidence of tendon pathology.•Dancing years were moderately correlated with achilles tendon thickness.•These abnormalities may not affect dance performance.