Thermal profiles over the Achilles tendon in a cohort of non-injured collegiate athletes over the course of a cross country season.

Objectives: To determine normal temperatures over the Achilles tendon over nine weeks.

Design: A prospective cohort study with nine weeks of observation.

Setting: University's Human Biomechanics and Physiology Laboratory.

Participants: Male or female competitive runners running at least 25 miles per week who did not report pain in the region of the Achilles over 9 weeks of data collection.

Main Outcome Measure: Thermal images taken at the same time and day of the week, were used to measure the temperature of the skin over the Achilles tendon.

Results: Seventeen athletes were eligible for analysis. The Achilles tendon temperatures were right 28.7 °C ± 1.3 °C, left 28.8 °C ± 1.3 °C. ICC demonstrated a very high consistency and minimal variations in temperatures (right 0.86 (95% CI = 0.58, 0.98), left 0.79 (95% CI = 0.38, 0.97). The mean difference between sides over the season was 0.50 °C ± 0.43 °C (p = 0.681). A decreasing trend in the Achilles tendon temperatures as the season progressed was observed.

Conclusion: This is the first report of normal thermal profiles over an extended period. Variations in Achilles temperatures left to right, and over time were not significant. The decreasing temperature trend over the season warrants further investigation.