Cross-cultural an Reliability and Validity Evaluation of TENDINS-A in Spain

Volunteers who want to participate in the study will read the general information of the study and sign the informed consent to participate in the study. Once the informed consent has been read and delivered, the evaluator will check that they meet the inclusion criteria. After the data collection, a randomization (Epidat V4.0) of the selected subjects will be carried out to assign them to one of the intervention groups. Patients must present Achilles pathology and will be recruited through a network of physiotherapy clinics distributed across Spain. The physiotherapist responsible for their treatment will invite them to participate in the study by providing a QR code granting access to all relevant study documentation. This documentation will include a checkbox in which the patient must indicate that, after reading all the pertinent information, they consent to participate. Without this explicit consent, marked via the checkbox, participation will not be possible. Once consent is provided, the patient will gain access to three questionnaires to be completed at the same time: VISA-A, FAOS, and TENDINS-A. After 48 hours, they will receive a link to complete the TENDINS-A retest. When the participant has completed all four questionnaires (VISA-A, FAOS, TENDINS-A, and the TENDINS-A retest), their participation in the study will be considered complete. The sample size will be calculated following COSMIN recommendations, aiming for a minimum of more than 100 participants to ensure excellent reliability.