Does the Gillet test assess sacroiliac motion or asymmetric one-legged stance strategies?

The results are consistent with there being left-right differences in gluteus medius and biceps femoris activation among asymptomatic individuals that result in different balancing strategies during one-legged stance. This may create the appearance of relative PSIS/SB displacement, even though the results of Gillet testing can be wholly or partially explained by pelvic obliquity owing to muscle function asymmetry. This study questions the validity of the upright Gillet test for sacroiliac motion.