Yoga is one of six classic systems of Hindu philosophy whose roots date back 5,000 years. There are four classic Yogas, and they are progressive in nature; i.e., Karma Yoga (right acts and actions), Bhakti Yoga (devotion), Raja Yoga (meditation) and Jnana Yoga (inner wisdom or enlightenment).
The classic four yogas have expanded into several other forms of Yoga. Hatha Yoga (worshipful poses), for example, is part of Raja Yoga training. Some of the other forms of Yoga are Nada Yoga (music), Mantra and Japa Yoga (chanting and on beads)and Kundalini Yoga (study of the psychic centers or chakras).