Validation of the FASH (Functional Assessment Scale for Acute Hamstring Injuries) questionnaire for German-speaking football players

BACKGROUND: The FASH (Functional Assessment Scale for Acute Hamstring Injuries) questionnaire has been recently developed as a disease-specific self-administered questionnaire for use in Greek, English, and German languages. Its psychometric qualities (validity and reliability) were tested only in Greek-speaking patients mainly representing track and field athletes. As hamstring injuries represent the most common football injury, we tested the validity and reliability of the FASH-G (G = German version) questionnaire in German-speaking footballers suffering from acute hamstring injuries. METHODS: The FASH-G questionnaire was tested for reliability and validity, in 16 footballers with hamstring injuries (patients’ group), 77 asymptomatic footballers (healthy group), and 19 field hockey players (at-risk group). Known-group validity was tested by comparing the total FASH-G scores of the injured and non-injured groups. Reliability of the FASH-G questionnaire was analysed in 18 asymptomatic footballers using the intra-class coefficient. RESULTS: Known-group validity was demonstrated by significant differences between injured and non-injured participants (p < 0.001). The FASH-G exhibited very good test–retest reliability (intra-class correlation coefficient = 0.982, p < 0.001). Internal consistency was excellent (α = 0.938). Compared with the results presented in the original publication, no statistical differences were found between healthy athletes (p = 0.257), but patients’ groups and at-risk groups presented scoring differences (p = 0.040 and <0.001, respectively). CONCLUSIONS: The FASH-G is a valid and reliable instrument to assess and determine the severity of hamstring injuries in German footballers.