The Effect of Yoga Postures on Balance, Flexibility, and Strength in Healthy High School Females

Objective The purpose of this study was to document the effects of yoga interventions on balance, flexibility, and strength in adolescent girls 14 to 18 years. Study Design Quasi-experimental, nonrandomized. Background Research on the effects of yoga on balance, flexibility, and strength has focused on adults, although yoga is being marketed to all ages. Methods and Measures A convenience sample of 33 female adolescents participated in yoga training 2 times per week and a walking program 3 times per week, for 7 weeks. The instructor-led group received instruction from a registered yoga therapist in person, while the video-led group watched a tape of the instructor-led session. Pre- and post-measurements of weight, hamstring flexibility, body fat, strength, and balance were collected. Means were computed for all variables. Levene's tests for equality of variances were run to determine baseline homogeneity. Histograms with a normal curve superimposed were drawn to check for normal distribution. Repeated-measures general linear model tests were run to test for both within- and between-subjects factors, as well as interactions between the two. Results Data were normally distributed and groups were not significantly different at baseline (P ≥ .05). There was a statistically significant within-subject difference (pretest to posttest) for range-of-motion right (P = .034) and range-of-motion left (P = .036) as measured by the 90/90 hamstring flexibility test. There were no statistically significant differences between the instructor- and video-led groups for any of the measured variables. Conclusions Yoga may be a useful adjunct to therapy programs and provide a method to keep this age group interested in exercise.