Criterion-related validity of sit-and-reach and modified sit-and-reach test for estimating hamstring flexibility in children and adolescents aged 6-17 years.

The purpose of the present study was to examine the criterion-related validity of the sit-and-reach test (SRT) and the modified sit-and-reach test (MSRT) for estimating hamstring flexibility in children and adolescents as well as to determine whether the MSRT is more valid than the SRT. A total of 87 (45 boys and 42 girls) children (6-12 years old) and adolescents (13-17 years old) performed the SRT and the MSRT. Hamstring flexibility was measured with goniometry through the passive straight-leg raise test. Regression analysis was performed to study the association of SRT and MSRT with hamstring flexibility (criterion measure). The SRT was associated with hamstring flexibility in both children (beta=1.089, R (2)=0.281, p=0.001) and adolescents (beta=0.690, R (2)=0.333, p=0.004). The MSRT was also associated with hamstring flexibility in both children (beta=1.296, R (2)=0.298, p<0.001) and adolescents (beta=0.588, R (2)=0.243, p=0.027). It is concluded that the criterion-related validity of the SRT and the MSRT for estimating hamstring flexibility is weak. The present data do not support that the MSRT is a more valid method than the SRT in children and adolescents. Georg Thieme Verlag KG Stuttgart.