The impact of various anthropometric and flexibility measurements on the sit-and-reach test

This study sought to determine which components of anthropometry and leg/back flexibility best contribute to performance of the sit-and-reach (S&R). It also examined relationships among selected back and lower extremity flexibility tests. Thirty-four healthy college-age women performed 5 flexibility tests: (a) S&R, (b) Schober-L for lumbar spine flexibility, (c) Schuber-L+T for thoracic and lumbar spine flexibility, (d) straight-leg raise (SLR) for hamstring flexibility, and (e) ankle dorsiflexion (DF) for ankle plantar-flexor flexibility. Statistical analysis included the use of correlation matrices among all measurements of flexibility and anthropometry. Also, a stepwise regression model was used to establish the best flexibility and anthropometric predictors of performance on the S&R. The level of association between S&R and SLR performance was found to be r = 0.78 (p < 0.01). All other flexibility tests and anthropometry variables (leg and arm length) were not as well associated with S&R performance. In conclusion, S&R performance was almost exclusively determined by hamstring flexibility. Also, ankle plantar-flexor, hamstring, and back flexibility were poorly correlated, indicating a need for specific flexibility measurements on each joint or muscle group.