Translation and Psychometric Validation of an Italian Version of the Dance Functional Outcome Survey DFOS-IT

The DFOS is a dance-specific, lower extremity and low back functional outcome measure, the first and only existing at the moment.

The DFOS-IT questionnaire will be developed involving forward-backward translation, a final re-evaluation made by a representative multidisciplinary expert committee and the realization of a prefinal version to establish a proper correspondence with the original English latest version.

A factor analysis and analyses of internal consistency, construct validity, internal responsiveness and sensitivity will be conducted. The reliability will be measured for internal consistency (Cronbach α) and a factor analysis will be applied to analyse the internal structure. The divergent validity will be measured by comparing the data obtained from the compilation of the DFOS-IT with those of the SF-36 to evaluate the psychometric properties and the equivalence of the results adapted to the Italian language and culture.

The validation of the psychometric properties of the instrument will start after it will been administered digitally, via a link to a website built using LimeSurvey, an application based on a MySQL database that allows the realization of online surveys, to a sample population of at least 140 dancers (10 subjects for each item of DFOS-IT) professionals or pre-professionals of age recruited through companies, professional academies, dance high schools and health professionals working with dancers. Through this link, from the time it will be online up to 30 September 2019, the dancers who will give their informed consent to their voluntary participation, will be able to access the online questionnaire.

Upon enrollment, dancers will answer a demographics questionnaire, the DFOS-IT, and the SF-36. If they will take part in the reliability portion, then they filled out the DFOS-IT a second time within 4 to 9 days and, if in the responsiveness testing, a third time after 4-months.

For the statistical analysis standard psychometric techniques will be used, such as reliability assessments, convergent and discriminant validity tests of each item and of the construct in its entirety, empirical validity tests in relation to the clinical status and formal tests to assess their accuracy to ends to test the hypotheses.

The investigators hypothesize to be able to reproduce a tool that reflects the characteristics of the DOFS in the original language and therefore it will prove to have, even in its Italian version, an acceptable psychometric performance as an outcome and screening measure for dancers. The DFOS-IT will show to be a useful tool to monitor both healthy state and functional limitation following lower extremity or low back injury in adult ballet and modern dancers.

For all dancers, inclusion criteria :

• A minimum of 3 years of dance training (classical, contemporary, modern-jazz ..)
• An Intermediate to expert skill level
• 18 years of age or older

For healthy dancers subgroup, inclusion criteria:

• No low back or lower extremity injury in the previous 3 months.

For injured dancers subgroup, inclusion criteria:

• at least one low back or lower extremity injury in the previous 3 months.

For all dancers exclusion criteria:

• Non-Italian speaking
• Pregnancy
• Current active disease processes other from a musculoskeletal injury in the low back or lower extremity.