Is it allowed for Muslims to do yoga or meditation?
Yoga and meditation are basically religious rituals. According to Islam, staying or sitting in front of Hindu gods/goddesses, sending energy to the universe, establishing a connection to the ancestors and asking them for help, saying Hindi mantras (words) are pagan beliefs and shirk (associationism). Therefore they are not allowed for Muslims.
However, it’s not a sin to do physical and mental relaxation exercises that only concern the sports aspect of yoga or meditation without adding any religious content.
Some examples of Hindu mantras (Thomas Ashley-Ferrard, Mantra Healing):
Om Shri Dhanvantre Namaha: Greetings and respect to the god Dhanvantre, who represents health and healing.
Om Gum Ganapataye Namaha: Greetings and respect to god Ganesha.
Om Nama Shivaya: Greetings and respect to the god Shiva.
Om (aum) symbolizes the three great Hindu gods, Brahma, Vishnu, and Shiva.