We know that running has many benefits for the body and mind – it helps improve cardiovascular fitness and reduces the risk for heart attack, stroke and myriad of other health conditions, including diabetes.
The physical loading of muscles and tendons improves the strength of those tissues. A similar effect happens to the bones.
The act of take-off and landing on every stride loads the bones, under the effect of gravity to initiate a process termed “remodelling,” which is essentially laying down new bone.
This process of bone strengthening is similar, though not identical, to what happens to the knee cartilage. By moderately loading it in a regular way as we do when we run, the cartilage get nutrition, lubrication and, therefore, maintains its strength and integrity.
Until recently, there have been few studies done on the effects of exercise, in general, and running, specifically, on the spinal discs.
A study done last year at Deakin University and published in April looked at the effect running has on intervertebral discs.
Spinal discs have been the subject of much study of actions that are harmful to them.
Flexion (bending forward) in a sustained or frequent manner, loading with a high compressive force, especially while rotating or bending, have all been shown to be detrimental to the integrity of spinal discs.
However, this study looked at the effects on spinal discs, from walking and running at different speeds and found some interesting results.
The study showed that long distance runners and joggers had significantly better quality and health of the spinal discs than the non-athletic population.
This effect was consistent across gender, age and spinal levels. Runners had more water content (hydration), improved physical components of the discs (nucleus and fibrous ring) showed growth (hypertrophy) and, thus, disc heights were greater than non-athletes.
They also found that all spinal levels that were measured in the study (lower thoracic to lumbar) benefitted from running, but that greater benefits were found at the lowest levels in the spine.
This makes sense from a hypothesized tissue model of the experiment since the disc at the bottom of the spine (L5-S1) would endure the most load due to the effect of gravity on the entire upper body.
These findings are significant because adverse spinal loading with bending has been shown to contribute to spinal disc degeneration. Walking or running in an upright position seems to have the opposite effect.
The other significant finding of the study is that there appears to be an optimal “window” of speed and load that promotes disc health.
All speeds contributed to the health effect, but walking or slow to moderate running at about 2 metres per second (4.5 mph) promoted the greatest effect, after which going any faster did not further improve the beneficial effect.
The authors noted that loading the spine outside of the “window,” either with high impact or with sedentary behaviour, contributes to a degenerative effect.
• westcoastkinesiology.com.