Mediators of Yoga and Stretching for Chronic Low Back Pain

Abstract

Although yoga is an effective treatment for chronic low back pain, little is known about the mechanisms responsible for its benefits. In a trial comparing yoga to intensive stretching and self-care, we explored whether physical (hours of back exercise/week), cognitive (fear avoidance, body awareness, and self-efficacy), affective (psychological distress, perceived stress, positive states of mind, and sleep), and physiological factors (cortisol, DHEA) mediated the effects of yoga or stretching on back-related dysfunction (Roland-Morris Disability Scale (RDQ)). For yoga, 36% of the effect on 12-week RDQ was mediated by increased self-efficacy, 18% by sleep disturbance, 9% by hours of back exercise, and 61% by the best combination of all possible mediators (6 mediators). For stretching, 23% of the effect was mediated by increased self-efficacy, 14% by days of back exercise, and 50% by the best combination of all possible mediators (7 mediators). In open-ended questions, ≥20% of participants noted the following treatment benefits: learning new exercises (both groups), relaxation, increased awareness, and the benefits of breathing (yoga), benefits of regular practice (stretching). Although both self-efficacy and hours of back exercise were the strongest mediators for each intervention, compared to self-care, qualitative data suggest that they may exert their benefits through partially distinct mechanisms.

Comparison groups in yoga research: A systematic review and critical evaluation of the literature

“…14 These results suggest that the effects of yoga on lower back pain may be due to stretching that occurs during asana, although both stretching and yoga may exert unique salutary effects as well. 29 …”

“…30 Thus yoga may provide the same psychological and physical benefits that other types of exercise do, as well as providing additional benefits, such as relaxation. 29 For example, a study of yoga in healthy participants in which investigators compared yoga to walking found that those in the yoga condition showed greater increases in positive mood and reductions in anxiety. 31 Investigators designed this study to test whether yoga adds to the known effects of physical exercise in improving mood and reducing anxiety, and carefully controlled for staff attention and interaction as well as energy expenditure.…”

Yoga research review

“…In a study on mediators of yoga and stretching for low back pain, physical factors were explored (including hours of back exercise per week), cognitive factors (including fear avoidance, body awareness and self-efficacy), affective factors (including psychological distress, perceived stress, positive states of mind and sleep) and physiological factors (including cortisol) [92]. The findings suggested that 36% of the pain reduction following 12 weeks of yoga was mediated by increased self -efficacy, 18% by sleep disturbance, 9% by hours of back exercise and 61% by a combination of the other factors.…”

Mechanisms, mechanisms, mechanisms: it really does all boil down to mechanisms

“…We could identify key therapeutic mechanisms within these treatments by launching comprehensive and well-powered studies that incorporate multiple psychosocial chronic pain treatments and multiple mechanisms – a la Turner and colleagues -- to compare and contrast mechanism effects on outcomes, to assess timing of mechanism changes during treatment, and, importantly, to determine which techniques best engender mechanism changes. Indeed, some form of behavioral activation – physical exercise [16]; stretching [15] – may represent particularly potent techniques to achieve not only behavioral changes, but what may emerge as crucial cognitive changes (i.e., increased self-efficacy). Once critical mechanisms are identified, we can devote energy to improving techniques and processes that fully engage and maximize the impact of these factors, when to engage them during treatment, and which combinations of mechanisms should be engaged for maximum benefit.…”