[Training adaptation of the Achilles tendon in competitive athletes--sonographic standard values for the Achilles tendon].

BACKGROUND

Current theories and empirical results regarding the sonographic dimensions of the Achilles tendon as well as an alleged training adaptation of the tendon in competitive athletes are tested for the first time in a large in vivo sample. The pathological validity of a thickened tendon in competitive athletes is under scrutiny.

MATERIAL AND METHOD

In addition to 202 national squad athletes from the German track and field federation, 199 age-matched normal individuals were examined sonographically. The portable ultrasound scanner Just Vision was used to compare 404 Achilles tendons of athletes with 398 Achilles tendons of normal individuals as to tendon diameter. Furthermore, pathologies were assessed.

RESULTS

Achilles tendon diameter at the calcanear insertion was 4.2 ± 0.72 mm on average. Athletes' tendons were thicker than normal tendons (p < 0.001) - athletes, however, also reported more clinical symptoms (p < 0.001). In athletes, increasing diameters were associated with more clinical problems as opposed to normal individuals. At the tendon waist, diameters above 6.0 mm were very likely to go along with pathologies.

CONCLUSIONS

For the first time, valid data of Achilles tendon diameters in competitive athletes and normal individuals have been presented. The emerging pattern of results clearly contradicts the notion of a physiological training adaptation of the Achilles tendon.