Background Transient changes in Achilles tendon structure are known to occur post exercise, it is unknown whether completing an ironman affects tendon structure.

Objective Assess the effect of an ironman on Achilles tendon structure.

Design Case study of a subject completing an ironman triathlon. The study utilised Ultrasound tissue characterization (UTC) scanning to quantify tendon structure pre and post activity. The UTC scan was completed 1 day prior to the Ironman and on day 2 by one examiner. The quantification of the UTC scan was completed by two experienced users who were blinded to the scan order.

Setting UK University.

Patients (or Participants) 49 year old male subject.

Interventions (or Assessment of Risk Factors) An ironman triathlon involves 3.86 km swim, 180.25 km bicycle ride and a marathon (42.20 km).

Main Outcome Measurements UTC quantification of Achilles tendon using percentage volume of each of the four echo types, tendon volume and mean cross-sectional area (mCSA).

Results Data is presented as the mean of the two examiners results. The mCSA increased by 10.7 mm² and 5.4 mm² on the right and left Achilles respectively. Tendon volume of the right Achilles tendon increased by 321.8 mm³ and whilst the left increased by 162.9 mm³. Data for the right and left leg were combined with the mean change in percentage of the different echo types presented post intervention. Echo type I increased by 1.7%, echo type II increased by 0.6% whilst echo type III and IV reduced by 1.7% and 0.6% respectively.

Conclusions The results indicate a change in Achilles tendon volume, mCSA and percentage of the different echo types post ironman. This preliminary study suggests that further work is required to assess alterations in Achilles tendon post ironman, specifically this work should determine if this change is observable in a larger group of athletes and whether this change is transient in nature.