For this eight-week study, they were told to sit for 56 minutes a day for five to seven days per week during the first week. Then for each week, the sitting time was increase by 10 percent. By the sixth week, they sat for 90 minutes per day and maintained this duration for the remaining weeks. All subjects went through three core endurance tests which were the Sorensen hold, isometric trunk flexion, and side plank tests.
After the study period, the subjects did another round of the exercise tests. Those who were in the stability ball chair group had higher muscular endurance for the Sorenson hold and isometric trunk flexion tests than those who sat on a regular chair. However, there were no significant differences among the NPRS and ODI reports and the side plank test. In other words, the amount of back pain and perception of disability were more or less alike.
Limitations of this study include gender bias (81% female), sample bias (size and university setting), ball-sitting duration (may not reflect real-life settings), and accountability. The sample did not discriminate different kinds of low back pain and looked a general population. However, the researchers pointed out that some of the strengths of this study include a larger sample size than previous similar studies and this study is a randomized, crossover design, which “helped to control for personal and demographic variables.”
Still, they did not find that sitting on a stability ball chair “prevented, increased, or decreased LBP or disability.” They suggested clinicians “should rely on other evidence-based treatments for LBP.”
This study was sort of based on another study by Schult et al. that has a similar setup and purpose. While most of the subjects who sat on a stability ball or a stability ball chair reported having better posture and higher energy levels at work than the control group who sat on a typical office chair, “42% of stability ball users and 45% of stability ball chair users reported some pain with use” versus 48% of office chair users at baseline. (5) However, the researchers found that every time the subjects rotate to a different seat (ball, ball chair, office chair), there are reports of less back pain. This likely indicate that it is not the type of chair or sitting position that aggravates or alleviates pain, but it's the timing or lack of variability in sitting that influences pain.
Schult et al. also cited that there is a weak support for an association between sitting and low back pain. (1-3) Thus, biomechanical and structural factors may not be huge contributors after all. The key to understanding back pain and what are the likely factors that cause pain is understanding pain itself based on current science, such as the neuromatrix theory of pain proposed by Dr. Ronald Melzack and Dr. Patrick Wall. (7) (Physiotherapist Diane Jacobs breaks down parts of that paper pretty well here.)
Sure, posture, movement, and strength do play roles in contributing or alleviating back pain, but they are not entirely to blame nor should therapists be obsessed with them. The bounciness of stability balls could provide some sitting and movement variability, which may evoke the kid inside them to play. Stability ball chairs and similar bouncy seats may not be the solution to “curing” back pain nor are they likely be better than a regular office chair, but perhaps — based on these studies — switching to different types of seats and moving more often rather than being a statue (even with “good” posture!) is most likely a better solution to alleviate low back pain.
And of course, stability balls seem much more fun than office chairs.
1. Hartvigsen J, Leboeuf-Yde C, Lings S, Corder EH. Is sitting-while-at-work associated with low back pain? A systematic, critical literature review. Scand J Public Health. 2000 Sep;28(3):230-9.
2. Lis AM, Black KM, Korn H, Nordin M. Association between sitting and occupational LBP. European Spine Journal. 2007;16(2):283-298. doi:10.1007/s00586-006-0143-7.
3. Chen SM1, Liu MF, Cook J, Bass S, Lo SK. Sedentary lifestyle as a risk factor for low back pain: a systematic review. Int Arch Occup Environ Health. 2009 Jul;82(7):797-806. doi: 10.1007/s00420-009-0410-0.
4. Elliott TL, Marshall KS, Lake DA, Wofford NH, Davies GJ. The Effect of Sitting on Stability Balls on Nonspecific Lower Back Pain, Disability, and Core Endurance: A Randomized Controlled Crossover Study. Spine. 2016 Sep 15;41(18):E1074-80. doi: 10.1097/BRS.0000000000001576.
5. Schult TM, Awosika ER, Schmunk SK, Hodgson MJ, Heymach BL, Parker CD. Sitting on stability balls: biomechanics evaluation in a workplace setting. J Occup Environ Hyg. 2013;10(2):55-63. doi: 10.1080/15459624.2012.748324.
6. Jackson JA, Banerjee-Guénette P, Gregory DE, Callaghan JP. Should we be more on the ball? The efficacy of accommodation training on lumbar spine posture, muscle activity, and perceived discomfort during stability ball sitting. Hum Factors. 2013 Dec;55(6):1064-76.
7. Melzack R, Katz J. Pain. WIREs Cogn Sci. 2013. 4: 1–15. doi:10.1002/wcs.1201