TENDINopathy Severity Assessment-Achilles: a study protocol for cross-cultural adaptation and psychometric properties patient-reported outcome instrument in Persian athletes with Achilles tendinopathy.

Patient-reported outcome measurements (PROMs) are important to evaluate the impact of clinical practice in athletes with Achilles tendinopathy (AT). The TENDINopathy Severity assessment-Achilles (TENDINS-A) is a PROM that measures the pain, symptoms and physical function associated with AT. This study aims to translate, cross-culturally adapt and measure the properties of the Persian language version of the TENDINS-A (Persian-TENDINS-A) in athletes with AT. According to the COnsensus-based Standards for selecting health Measurement INstruments guidelines, 100 athletes with AT will be required for test-retest reliability, construct validity and internal consistency. Analyses will include confirmatory factor analysis, internal consistency, construct validity, SE of measurement, agreement, smallest detectable change, and floor and ceiling effects. Test-retest reliability of the Persian-TENDINS-A will be evaluated within 2-3 days for the Persian-TENDINS-A. Hypothesis testing of the Persian-TENDINS-A will be determined using a Pearson correlation of a single point in time between Persian-TENDINS-A scores with the Victorian Institute of Sports Assessment-Achilles and Pain Self-Efficacy Questionnaires. The study protocol was approved by the Ethics Committee of the University of Zabol (approval ID: IR.UOZ. REC.1403.004) based on the Declaration of Helsinki. Findings from this study will be disseminated to the athletes, clinicians and researchers through peer-reviewed journals and national and international conferences.