Yoga means attachment, when a spirit meets in god’s spirit is called Yoga. Preceptor Patnajali has described very many kinds of function of exercises in Yoga Darshan. He said eight parts of exercises and these eight parts of exercises is called Ashtanga. These are;
Yam, Niyam, Partiyahar, Parnayaam, Aassan, Dharna, Dheyan, Samadhi
Yoga is a group of physical, mental, and spiritual practices or disciplines which originated in ancient India
Physical & mental problems disappear completely doing Ashtanga yoga and people get achievement near god but in present age, there are very many forms of yoga. Hatha yoga, also called hatha vidya, is a kind of yoga focusing on physical and mental strength building exercises. Yoga is become popular in different names in present age. For example;
Power Yoga, Vikram Yoga, Hot Yoga, Aayanger Yoga
Yoga is performed in different ways and so we cannot say those methods are wrong because our body also do benefited from those yoga. If you are completely fit, do such practices with competent trainers who can do exercise according to your health & fitness otherwise you may be in wrong way and get loss your health.