The promise of yoga – is the hype justified?


INTRODUCTION: Ross and Thomas (2010, p. 3) found in their meta-analysis that "yoga interventions appeared to be equal or superior to exercise in nearly every outcome measured except those involving physical fitness". Therefore, it seems that the often-recorded more positive effects of yoga on stress (compared to exercise in general) may not be due to changes in physical fitness but are more likely to affect psychological resources in a way that physical exercise alone cannot. METHOD: This study examines the effects of a four-week yoga-intervention compared to a group-fitness-intervention on cognitive functions (LPS-2), mental (PSS-10; PANAS), and physical well-being (PSI) in young adults. Participants were randomly assigned to the yoga- (n = 16, n male/female= 4/12, Mage=26.25, SD=4.01) and the control-group (n = 15, n male/female= 3/12, Mage=21.67, SD=2.26). ANOVAs with group and between-subject-factor and age and sex as covariates were conducted. RESULT: Sex and age showed no significant effect on any of the measures. Both groups improved over time only in cognitive speed (F(1,27)=3.13, p=.036 eta2=.153). Significant group-time interaction effects were observable for perceived stress levels whereas the fitness group reported a greater reduction in stress levels (F(1,27)=4.39, p<.05, eta2=.14). Likewise tendencies for interaction effects were observed for positive affect (F(1,27)=3.13, p=.088 eta2=.109) and physical self (F(1,27)=3.13, p=.069, eta2=.117), . DISCUSSION: The results are contractional to Ross et al. (2010). This might be due to differences in the design of the reviewed studies. Hence studies on adequate intervention-periods, sensitivity for yoga-interventions in different age-groups, and output-effects of different yoga types are needed.