Bikram yoga is a controversial, intensive yoga practice founded by Bikram Choudhury in Los Angeles after Bikram's lifelong study of yoga in India. Bikram yoga uses 26 different yoga poses or asanas and is practiced in rooms heated to at least 105 degrees Fahrenheit and at 40% humidity. These extremely warm, humid conditions promote circulation and give you the best chance to deepen your flexibility without injury.
Many devotees of stretching, both yogic and otherwise, complain of injury and discomfort that could be avoided by sufficiently warming up the muscles and tendons before actively stretching them. The warmer the muscle, the more supple it is and susceptible to change, including the degree of flexibility it's capable of. Any dancer or runner will warn you of the dangers of extreme physical activity without properly stretching before and afterwards.
Typically, Bikram yoga classes last for 90 minutes. One of the reasons this practice is so controversial is because of Bikram's assertively copyrighted program. Practitioners must pay to undergo a specified training and certification is not possible without this program. While Bikram has sustained great criticism for his personal capital gain from his practice, it is after all a systematic program. I cannot imagine the communities of dance, acrobatics, or any other extreme physical endeavor demanding their right to receive their training for free.
Bikram yoga aims to detoxify the body through the high amount of sweating that occurs in these extreme conditions. Practitioners are warned not to eat before a class as this can lead to a heaviness and nausea due to the high heat and inverted poses. While increasing flexibility is an obvious plus in these rigorous classes, Bikram yoga seeks to heal, cleanse, stimulate, and reinvigorate every muscle system, organ, and joint of the body. Part of this process involves working through and with Bikram's Five Aspects of the Mind, which are discussed in other articles.