Development and Validation of a Questionnaire to Measure the Severity of Functional Limitations and Reduction of Sports Ability in German-speaking Patients with Exercise-induced Leg Pain

Background: Currently, there is no generally agreed measure available to quantify a subject's perceived severity of exercise-induced leg pain symptoms. The aim of this study was to develop and validate a questionnaire that measures the severity of symptoms that impact on function and sports ability in patients with exercise-induced leg pain.

Methods: The exercise-induced leg pain questionnaire for German-speaking patients (EILP-G) was developed in five steps: (1) initial item generation, (2) item reduction, (3) pretesting, (4) expert meeting and (5) validation. The resulting EILP-G was tested for reliability, validity and internal consistency in 20 patients with exercise-induced leg pain, 20 asymptomatic track and field athletes serving as a population at risk and 33 asymptomatic sport students.

Results: The patient group scored the EILP-G questionnaire significantly lower than both control groups (each p<0.001). Test-retest demonstrates an excellent reliability in all tested groups (Intraclass Correlation Coefficient, ICC=0.861-0.987). Concurrent validity of the EILP-G questionnaire showed a substantial agreement when correlated with the chronic exertional compartment syndrome classification system of Schepsis (r=-0.743; p<0.001). Internal consistency for the EILP-G questionnaire was 0.924.

Conclusions: EILP-G questionnaire is a valid and reliable self-administered and disease-related outcome tool to measure the severity of symptoms that impact on function and sports ability in patients with exercise-induced leg pain. It can be recommended as a robust tool for measuring the subjectively perceived severity in German-speaking patients with exercise-induced leg pain.