<qa>  What is the reverse direction of COP displacement before voluntary COP displacement?It is important to develop GI related APA tests and trainings. Researchers found that a perturbation applied before the COP displacement during GI could delay both GI and APA. This indicates that COP displacement has APA components. Our pilot study shows that there is a reverse direction of COP displacement before voluntary COP displacement, suggesting the existence of APA. 