Master, Sir, or Mam,
Hello.

Can anyone please tell me the application or purpose for movement #21 in Se-Jong.
21. Pull the left instep to the hollow of the right leg to form a right one-leg stance toward C while striking the left palm with the right back forearm.

Specifically, the reason the instep is pulled to the hollow of the leg in the one leg stance. At first I thought it might be for support, but if that were the case I would think it would be performed like that in other patterns.
Any insight is very appreciated.

Thank you, and TaeKwon.

Zac

Perform the movement by raising the knee only, then again bringing the foot into the knee hollow. The result being in that the application becomes much stronger. Therefore it is a reaction to the force.

 TN

Hello Master Nicholls.
Thank you very much Sir. Your response is very appreciated.
Taekwon.