Abstract
The Dance Functional Outcome Survey (DFOS) was developed as a self-report questionnaire for healthy and injured ballet and modern dancers, focusing on the low back and lower extremities. Our aim was to determine factor analysis and internal consistency of the 16 items and to investigate test-retest and equivalence reliability and validity of the DFOS compared to three orthopedic outcomes instruments. Data were collected from 80 healthy and injured adult ballet and modern pre-professional and professional dancers. DFOS Likert-type and visual analog scales were completed twice within 4-9 days to study test-retest reliability. The Cincinnati Knee Rating System, Olerud and Molander Foot-Ankle Questionnaire, and Oswestry Disability Index were used to assess concurrent validity using intraclass correlation coefficients in SPSS, p<0.05. To determine instrument dimensions and internal consistency of the items, we conducted exploratory factor analysis and calculated Cronbach's α in JASP. DFOS demonstrated single factor loading and high Cronbach's α; high test-retest repeatability and equivalence reliability ( r =0.74-0.99) and acceptable criterion validity compared to the orthopedic outcomes instruments (r≥0.67). These results support further study of a revised 14 item Likert-version DFOS for repeatability, validity and responsiveness.