40 Yoga scientiﬁc and theoretical basis of using yoga and Pilates in the management of CLBP. Yoga is a form of mind–body exercise which couples physical exercise with mental focus through breathing and meditation. There has been a dramatic increase in the popularity of yoga in America over the last decade. In 1998, a national survey on the prevalence of adult yoga use in the United States estimated that 15.0 million American adults had used yoga at least once in their lifetime and 7.4 million during the previous year [2]. Participators reported using yoga for both wellness and health issues; speciﬁcally, 21% of respondents using yoga in the previous 12 months practiced yoga for back or neck pain. More recently, according to the Yoga Research and Education Council Report on Yoga statistics, there were 15 million Americans practicing yoga more than three times weekly in 2003 [3]. Today, yoga classes are a regular ﬁxture at most health and ﬁtness clubs; in addition, private yoga studios abound, offering instruction in different styles of yoga. Yoga background and styles Hatha yoga, the yoga typically practiced in the United States, is only one part of the non-sectarian philosophical system of yoga that emerged from the Indian culture approximately 4,000 years ago. Hatha yoga is comprised of three aspects which are integrated with one another including (1) asanas or physical postures, (2) pranayama or breathing exercises and (3) meditation or relaxation. The postures are designed to increase ﬂexibility and strengthen the body in a controlled fashion as well as improve bal- ance. These poses are performed standing, sitting, reclining, or inverted and may involve forward bends, backward bends, twists, or balancing (see Figs. 1 and 2). Breathing exercises link the postures together and help the mind focus. A Hatha yoga class concludes with a short meditation session during which the participant lies supine with eyes closed while shifting attention inwardly to create a relaxed state of being. A yoga instructor typically leads a group of practitioners through a class lasting 60–90 min. There are many styles of Hatha yoga including Iyengar yoga, Viniyoga, Ashtanga yoga (also known as ‘‘power yoga’’), and Bikram (‘‘hot’’) yoga. Each of these forms of Hatha yoga has an unique approach. For example, Iyengar yoga is known for its emphasis on precise postural align- ment and utilizes ‘‘props’’ including blocks and straps to assist in positioning. Iyengar yoga is the most commonly practiced style of yoga in the United States [3]. The Curr Rev Musculoskelet Med (2008) 1:39–47 Fig. 1 Yoga pose—Triangle Viniyoga style is a relatively easy style of yoga to learn and emphasizes the individualized nature of the yoga practice. Asthanga yoga is known for its vigorous ﬂow of stan- dardized postures linked together by breath. In our opinion, this style of yoga is typically more suited for the inter- mediate or advanced practitioner. Finally, in Bikram yoga, a series of postures, each held for a speciﬁc length of time are typically performed in intense heat (105 F). It is notable that such temperatures may exacerbate heat-sen- sitive medical conditions. The yoga literature Literature evaluating the effectiveness of yoga for LBP is scant; a review of this subject revealed only four published randomized controlled studies. In 2004, Jacobs et al. con- ducted a feasibility study exploring an Iyengar yoga intervention for CLBP [3]. Fifty-two subjects who had made at least three visits to a health care provider for nonspeciﬁc LBP in the past 12 months were enrolled in this study. Participants were then randomly assigned to one of the two groups including 28 to the yoga group and 24 to