Running a Marathon-Its Influence on Achilles Tendon Structure.

CONTEXT: Several studies have been conducted to better understand the effect of load on the Achilles tendon structure. However, the effect of a high cumulative load consisting of repetitive cyclic movements, such as those that occur during the running of a marathon, on Achilles tendon structure is not yet clear. Clinicians, coaches, and athletes will benefit from knowledge about the effects of a marathon on the structure of the Achilles tendon.

OBJECTIVE

To investigate the short-term response of the Achilles tendon structure to running a marathon.

DESIGN

Case series (prospective).

SETTING

Sports medicine centers.

PATIENTS OR OTHER

PARTICIPANTS

Ten male nonelite runners who ran in a marathon.

MAIN OUTCOMES MEASURE(S): Tendon structure was assessed before and 2 and 7 days after a marathon using ultrasound tissue characterization (UTC), an imaging tool that quantifies tendon organization in 4 echo types (I-IV). Echo type I represents the most stable echo pattern, and echo type IV, the least stable.

RESULTS

At 7 days postmarathon, both the insertional and midportion structure changed significantly. At both sites, the percentage of echo type II increased (insertion P < .01; midportion P = .02) and the percentages of echo types III and IV decreased (type III: insertion P = .01; midportion P = .02; type IV: insertion P = .01; midportion P < .01). Additionally, at the insertion, the percentage of echo type I decreased (P < .01).

CONCLUSIONS

We observed the effects of running a marathon on the Achilles tendon structure 7 days after the event. Running the marathon combined with the activity performed shortly thereafter might have caused the changes in tendon structure. This result emphasizes the importance of sufficient recovery time after running a marathon to prevent overuse injuries.