Achilles tendon single bout and season long adaptations during early and late collegiate cross-country season.

AIMS

To examine single bout and season long Achilles tendon cross-sectional area (CSA) changes before and after running during the early and late cross-country season.

DESIGN

OBSERVATIONAL: repeated measures design study.

SETTING

Controlled laboratory setting.

PARTICIPANTS

This study consisted of 35 participants. The running group included 11 males and 9 females, the control group was 8 males and 7 females.

MAIN OUTCOME MEASURES

Diagnostic ultrasound images were taken before and after runners completed a common recovery run during the early and late cross-country season. Ultrasound images of control participants, who did not run, were taken following an averaged time that athletes spent running.

RESULTS

No significant tendon season long CSA increases occurred for runners (p = 0.453). Runners experienced significant Achilles tendon CSA decreases compared within subjects (p < 0.05) and between controls (p < 0.05). Significant CSA decreases occurred for runners during the early and late season run (p < 0.05) with greater percentages of decrease in the early season (p = 0.009). Male and female runners experienced similar CSA decreases while running (p = 0.696).

CONCLUSIONS

No Achilles tendon CSA increases occurred over the season. Significant Achilles tendon CSA decreases occurred while running during early and late season runs, but varied with larger CSA decreases occurring during the early season.