There is nothing wrong with reading from the Mushaf while one is stretching his or her leg or even lying down, wearing slippers etc.

Al-Bukhari and Muslim narrated that the Prophet (peace and blessings be upon him) used to lie in `A’ishah’s lap and recite Qur’an.

Imam Al-Nawawi commented: This indicates that it is permissible to read Qur’an while reclining and lying down.