Achilles tendinopathy is highly prevalent in runners, but its evolution is not easily predictable. The aim of this study is to evaluate the impact of clinical and social factors on the prognosis of acute (less than 3 months) Achilles tendinopathy in runners. Runners will be evaluated in person twice. At their first visit, data related to their training (frequency, intensity, …), their running pattern (cadence, foot contact angle) and shoes (minimalist index) will be collected. Moreover, an ultrasound evaluation of Achilles tendon will be performed. At one, two and three months after their initial evaluation, participants will receive a link to complete an online survey about their pain. Three months after their initial evaluation, a second ultrasound of Achilles tendon will be performed.

At their first visit, participants will read and sign the consent form. They will then fill self-report questionnaires about their pain (using the Victorian Institute of Sport Assessment for Achilles tendinopathy score and visual analog scale) and its impact on their activities, and they will be questioned on their training habits. Then, participants will be asked to run on a treadmill for five minutes at a comfortable speed. During the run, video will be recorded to evaluate to cadence and the foot contact angle. Finally, an ultrasound of Achilles tendon will be performed to evaluate thickness, area, echogenicity and inflammation of the tendon. All the images will be revised by a physician qualified in diagnostic ultrasound and the tendinopathy will be graded according to Matthew and al. model.

One, two and three months after their initial visit, participants will receive a questionnaire by email to quantify their pain. Moreover, three months after their initial visit, participants will come back in person to the laboratory. Information about their pain, training and treatment will be collected and a second ultrasound analysis will be performed.

Statistical analysis: Baseline data will be compared using independent t-test or a Mann-Whitney U test. Significant variables in the univariate analysis will be considered as potential predictor variables. Logistic analysis regression will then be performed to identify predictive factors for pain chronicity.

Inclusion Criteria:

• Have Achilles tendon pain for less than three months
• Run at least five kilometers per week
• Have a score on the Victorian Institute of Sports Assessment of Achilles tendinopathy of 80 or less
• Consent to the study

Exclusion Criteria:

• History of Achilles tendon surgery or rupture

Runners from Québec city region with Achilles tendon pain for less than three months