Structures within the human body are often viewed in different ways. Skeletal muscle tissue, for example, is considered adaptable with the capacity to become stronger in response to exercise. Other structures, such as spinal discs, are viewed more like machine parts, susceptible to activity related wear and tear and lacking the capacity to positively adapt to loads placed on the spine. With this perception it is a commonly held belief that activities like running may contribute to premature degenerative changes in the spinal discs, increasing the risk of the low back pain. But is this the right way to think about spinal discs in the lower back and how they respond to running?
Recent research from an Australian group compared the lumbar discs of 2 groups of runners to a sedentary group.¹ The participants of the study were all aged between 25 and 35. Each group had around 25 subjects and all had at least a 5 year history at their current activity level. The runners were divided into a lower mileage group (20-40 km/12.4-24.8 miles per week) and a higher mileage group (50 km/31 miles per week or more). MRI scans were used to measure properties considered key indicators of disc health.* The study found that both running groups had greater disc hypertrophy and better disc hydration than the sedentary group. In other words, their discs were thicker and had a better structural makeup, qualities that you want for one of the key spinal shock absorbers.
It is also worth highlighting a number of other key points from the study. The results showed that the changes in the runners’ discs were present at all of the intervertebral levels of the lumbar spine. Positive changes were prominent in the nucleus, which is the central part of the disc often associated with disc herniation pathology. The long distance runners demonstrated the greatest hypertrophy changes, however, no significant difference was found between the two running groups for any of the measurements. Finally, the study also collected accelerometry data and suggested that a slow jog or fast walking speed of 2 m/s (~4.5 mph) provides a sufficient stimulus to cause positive disc adaptations that were not seen with slower walking speeds.
It is fair to point out that this study is limited to a narrow age group, is not designed to follow the groups over time and cannot control for all of the possible variables that could influence the properties of a spinal disc. However, it does contribute to an extensive body of evidence supporting the health benefits of a good running program which on balance far outweighs any potential risks. It builds upon existing population studies which have not found an association between running and disc degeneration and have not found running to be a risk factor for disc herniation.² ³ Lumbar discs should be viewed as biologically active with the capacity to adapt to the right type of load. Given how common lower back pain is, it is always good to be reminded that we can be proactive and positively impact the health of our spines with the right exercise and activities.
* For those of you interested in the measurements taken, they included disc composition (hydration/proteoglycan content) and hypertrophy (disc height relative to vertebral body height).
Resources:
- Belavý, Daniel L, Quittner, Matthew J, Ridgers, Nicola, Ling, Yuan, Connell, David & Rantalainen, Timo. 2017. Running exercise strengthens the intervertebral disc. Scientific reports 7: 45975.
- Woolf, Shane K & Glaser, John A. 2004. Low back pain in running-based sports. Southern medical journal 97: 847-852.
- Mundt, Diane J, Kelsey, Jennifer L, Golden, Anne L, Panjabi, Manohar M, Pastides, Harris, Berg, Anne T, Sklar, Joseph & Hosea, Timothy. 1993. An epidemiologic study of sports and weight lifting as possible risk factors for herniated lumbar and cervical discs. The american journal of sports medicine 21: 854-860.
