The effect of sitting on stability balls on nonspecific lower back pain, disability, and core endurance

Study Design. Experimental randomized crossover. Objective. The aim of the study was to determine whether sitting on a ball for 90 min/d instead of a chair has an effect on low back pain (LBP), low back disability, and/or core muscle endurance. Summary of Background Data. LBP may result from prolonged sitting. It has been proposed that replacing chairs with stability balls can diminish LBP in those who sit for prolonged periods. Research on the topic is sparse and inconclusive. Methods. A total of 90 subjects (university students, staff, and faculty, ages 18-65, who sit ≥4 hr/d) were randomly assigned to the intervention or control group for the first part of the study. Baseline data were collected: Oswestry Disability Index, a numerical pain rating scale for LBP, and four core muscle endurance tests. For 8 weeks, the control group sat on their usual chair. The intervention group sat on stability balls 5 d/wk, increasing up to 90 min/d. Baseline measurements were repeated postintervention. After a washout period, subjects switched groups, and the procedures were repeated-70 completed participation in control group and 76 in intervention group. Results. There were no statistically significant differences for pain or disability in either group (P>0.05). Changes in isometric trunk flexion (P=0.001), nondominant side plank (P=0.008), and Sorensen (P=0.006) endurance scores were significant within the intervention group but not the control group. Between-group comparisons revealed a significant difference for isometric trunk flexion (P=0.005) and Sorensen endurance times (P=0.010). Analysis also showed that ball-sitting did not prevent an increase in LBP over the 8-week period. Conclusion. Ball-sitting had no significant effects on LBP or associated disability, but did improve core endurance in the sagittal plane. Although ball-sitting may be useful as an adjunct treatment for LBP when core muscles are involved, clinicians should rely on other, evidence-based treatments for LBP.