What is the meaning of the rapid movement of toes and feet when reciting Surat Ya-Sin and As-Saffat, and what is the advice in this situation?

If the movement of fingers and feet is caused by being affected by and taking heed of the Quran, then it is good; because the Quran makes the skins of those who fear their Lord shiver, and their hearts soften at the remembrance of Allah. Asma bint Abi Bakr mentioned that the Companions' eyes would tear up and their skins would shiver when the Quran was recited. However, if the reason is not being affected by the Quran, then it is advisable to continue reading and persevere in remembrance (dhikr).