According to new research conducted at Oregon Health & Science University, yoga exercises may have the power to combat fibromyalgia — a medical disorder characterized by chronic widespread pain.
The study involved 53 women, had a control group, and was randomised and blinded.
Comparison of the data for the two groups revealed that yoga appears to assist in combating a number of serious fibromyalgia symptoms, including pain, fatigue, stiffness, poor sleep, depression, poor memory, anxiety and poor balance. All of these improvements were shown to be not only statistically but also clinically significant, meaning the changes were large enough to have a practical impact on daily functioning. For example, pain was reduced in the yoga group by an average of 24 percent, fatigue by 30 percent and depression by 42 percent.
Oh, so yoga doesn't counteract fibromyalgia, so much as reduce some of the symptoms? As some of the commenters on that report note, there was also no comparison with exercise per se.
The actual published study is a little less triumphant. The intervention group actually undertook a range of therapies since yoga doesn't just include the traditional exercise component:
Each Yoga of Awareness class included approximately 40 min of gentle stretching poses (see details below), 25 min of mindfulness meditation (e.g., awareness of breath, awareness of awareness itself), 10 min of breathing techniques (e.g., full yogic breath, breathing into sensation), 20 min of didactic presentations on the application of yogic principles to optimal coping, and 25 min of group discussions (e.g., experiences while practicing yoga at home).
EoR wonders whether it was a synergistc effect, so that 'yoga' provided the stated improvements, or might it have been any one (or combination) of exercise, meditation, breathing techniques, presentations or group discussions? The authors also note that, while there were strong beneficial outcomes from their study,
Major limitations of our study should be noted. The generalizability of these preliminary findings is restricted by the small sample, the absence of follow-up, and over-reliance on self-report data. Moreover, as stated above, any conclusions are especially limited by the lack of an attention placebo or active control condition
The same issue of Pain also includes a paper on psychological interventions for fibromyalgia, reported in a Commentary as:
Using meta-analytic strategies, the review by Glombiewski et al.  (in this issue) on treatments for fibromyalgia provided conclusive evidence for the efficacy of psychological interventions in managing this enigmatic pain problem. Specifically, the authors reported that psychological treatments yielded significant reductions in pain, sleep problems, depression, functional status, and catastrophizing.
The same Commentary also notes, however:
As in all reviews, however, the Glombiewski et al. paper raised a number of questions that only additional research could meaningfully address. One issue is the weak methodological quality of many of the studies reviewed. The treatment literature on fibromyalgia, unfortunately, is notable for its lack of adequate controls, limited follow-up, inconsistencies in defining clinical outcomes, and confusion over rationally integrating treatment approaches with key symptoms. These methodological limitations have raised questions about the efficacy of potentially effective treatments and their systematic use in clinical practice.
Carson, J.W., Carson, K.M., Jones, K.D., Bennett, R.M., Wright, C.L., & Mist, S.D. (2010). A pilot randomized controlled trial of the Yoga of Awareness program in the management of fibromyalgia. Pain 151 (2010) 530–539.
Glombiewski, J.A., Sawyer, A.T., Gutermann, J., Koenig, K., Rief, W., & Hofmann, S.G. (2010). Psychological treatments for fibromyalgia: A meta-analysis. Pain 151 (2010) 280–295
Nicassio, P.M. (2010). Commentary: Psychological approaches are effective for fibromyalgia: Remaining issues and challenges. Pain 151 (2010) 245–246.