running

Running and disc height loss

Running and disc height loss occurs with moderate intensity after 30 minutes.

Many people complain about spinal-related pain in and around the act of running.  Here is a wonderful article from Medicine and Science in Sports and Exercise.1

Running is a form of spinal compression, but it is also a form of decompression.

These researchers found that 30 minutes of moderate running caused significant disc height loss in the spine. The discs lost about 6% of their height, which can be quite substantial if they are already compressed.

Background

Physical exercise is widely promoted for healthy individuals, and evidence is growing to support exercise training interventions for patients with chronic disease. American College of Sports Medicine guidelines recommend moderate-intensity cardiorespiratory exercise training for most adults or a combination of moderate- and vigorous-intensity exercise to achieve a total energy expenditure of Q500 to 1000 METIminIwkj1. Weight-bearing exercise modalities like walking and running are often advocated to maintain spinal health.

The two main types of spinal loading during ambulation are compressive loading and impact loading. Compressive loading occurs from weight-bearing activities, while impact loading occurs from the landing phase of impact activities like running. Running inflicts a ground reaction force of two to three times the body weight that lasts for 2-3 seconds and is transmitted to the spine. Precision stadiometry has been demonstrated to be a reliable method of measuring the change in total stature, which is assumed to occur when osmotic pressure in discal tissues is exceeded by the load on the spine, resulting in fluid being expelled from the intervertebral disc (IVD).

Magnetic resonance imaging (MRI) can be used to quantify the size of IVDs without exposing participants to harmful radiation. Midsagittal MRI analyses have demonstrated that static loading during sitting and walking causes reductions in IVD height in the lumbar vertebral region. Recently, 1 hour of running was demonstrated to reduce IVD height in the lumbar discs of long-distance running athletes. However, the influence of a recommended bout of moderate-intensity running on IVD height and volume remains unknown. The susceptibility of IVDs in the lumbar and thoracic regions to compression during exercise has not been quantified in healthy adults.

Experimental Design

This study utilized a single-group repeated-measures design, with participants attending three testing sessions on different days, separated by 3-8 days. Eight male volunteers (18–23 years of age) with no history of disease or back pain were informed about the potential risks of the study and gave written informed consent to participate. The experimental procedures were in accordance with the policy statement of the American College of Sports Medicine.

The first session was used to take preliminary measurements, familiarize the participants with anthropometry and treadmill running, and calculate the exercise intensity required for the exercise trial. During the second and third sessions, participants reported to the clinic within 30 minutes of rising from bed, after at least 10 hours of bed rest and having undergone minimal ambulatory activity. During the second session, venous blood samples were taken and baseline measurements of body mass and stature were obtained before spinal MRI examination. During the third session, the same measurements were repeated on arrival (pre-exercise) and after completing 30 minutes of treadmill running at 70% HR reserve (post-exercise).

Preliminary procedures involved completing baseline measurements of stature (Portable Stadiometer; Holtain, UK) and body mass (model 712; seca,ancement of Kinanthropometry guidelines using a portable stadiometer (Holtain). Blood sampling and analyses were carried out using anticoagulant ethylenediaminetetraacetic acid, plasma osmolality was measured in duplicate by freezing point depression using a cryoscopic osmometer (Osmomat 030;  Germany), followed by a progressive treadmill run to exhaustion. Standing stature was measured according to the International Society for the AdvGonotec, Berlin, Germany), and a progressive treadmill run was performed.

Three MRI examinations (baseline, pre-exercise, and post-exercise) were carried out in the supine position, lasting between 7 and 10 minutes. The MRI protocol was performed on a 1.5-T high-definition 16-channel system (GE Medical Systems, Waukesha, WI). Sagittal T2 fast relaxation fast spin echo sequences were used to image the cervical, dorsal, and lumbar regions after a 3-plane localizer. Intra-observer reliability was determined using 10 repeated measurements of a randomly selected example for all IVD locations.

Statistical analysis was carried out using Predictive Analytics Software Statistics (version 18.0; SPSS Inc., Chicago, IL). Shapiro–Wilk tests were conducted to assess the normality of all data. Group data were expressed as mean T SD and statistical significance was set at P G 0.05. Two-way repeated-measure ANOVAs were used to determine the influence of day-to-day variation and exercise (timing: baseline, pre-exercise, and post-exercise) and IVD (IVD: 17 IVD locations) on IVD height and volume. Significant main effects of timing and IVD were further investigated using pairwise comparisons with Bonferroni adjustment. One-way repeated-measure ANOVAs were used to evaluate the influence of timing on plasma osmolality and stature.

Bonferroni adjustments were included in the calculations for the 95% CIs for differences between means.


Results

The study involved participants with plasma osmolality of 289 T 1 and 285 T 2 mOsmIkgj1, respectively. They had a mean IVD height of 0.33 mm and a mean IVD volume of 0.34 T 0.09 mm. The mean IVD height in the thoracic and lumbar regions varied between baseline, pre-exercise, and post-exercise scans. Exercise-induced changes in mean IVD height were greater in the thoracic region (7.7% T 1.2%) compared to the lumbar region (3.7% T 0.6%). The total exercise-induced loss in IVD height within the thoracic and lumbar regions was 4.12 T 1.10 and 1.45 T 0.45 mm, respectively.

Calculated IVD volumes were different between MRI scans, with day-to-day variations of 0.04 mm3 or 0.4% T 0.6%. Exercise-induced reductions in mean IVD volume were 754 mm3 or 6.9% T 1.0% of pre-exercise values. Although exercise-induced losses in total IVD volume were greater in the lumbar region (3122 mm3 compared to the thoracic region), the relative change in IVD volume in the thoracic and lumbar regions was 8.4% T 1.4% and 4.2% T 0.6%, respectively.

Stature also differed across measurements, with mean differences of 0.4mm. Exercise-induced changes in stature equated to a shrinkage of 8.1 T 0.6 mm (95% CI, 6.1–10.1 mm).

Running and IVD

Discussion and Conclusion

This study aimed to investigate the impact of moderate-intensity treadmill running on the height and volume of discs (IVDs) in the thoracic and lumbar regions of the spine. The results showed that 30 minutes of treadmill running resulted in a 6.3% reduction in mean IVD height and a 6.9% reduction in mean IVD volume. Resting mean IVD height and volume were similar across days, with the day-to-day variation being 0.6% T 0.6% and 0.4% T 0.6%, respectively. Exercise-induced changes in IVD height and volume were evident in IVDs in the thoracic and lumbar regions, making this the first study to demonstrate that IVD height and volume are reduced throughout the thoracic and lumbar regions of the spine after an acute bout of running exercise.

The study demonstrated that 30 minutes of treadmill running at 70% HRreserve resulted in an 8.1 T 0.6-mm loss of total stature, which is similar to the amount of stature loss previously reported after marathon runners completed 30 minutes of treadmill running at 100% of race pace. The magnitude of loss in stature is significant when compared with usual diurnal changes of 15-19 mm. Stature measurements were taken using the International Society for the Advancement of Kinanthropometry measurement techniques with a commercially manufactured precision stadiometer.

The study also found that treadmill running at 70% HRreserve caused a loss of vertical height in the lumbar vertebral region of 4.4 T 0.8 mm. However, direct measurements from X-ray images provide a good contrast between the vertebral endplate and connecting tissues. Still, the lack of depth perception makes this imaging method impractical for quantifying mean IVD height and volume. In contrast, MRI provides a three-dimensional reconstruction of IVDs using a non-radiant imaging technique that has been shown to provide reproducible and reliable volume measurements for lumbar IVDs.

The mean loss in IVD height calculated in the current study (0.33 mm; 95% CI, 0.27–0.39 mm) was less than the reported reduction in mean lumbar IVD height (0.66 to 1.10 mm) after athletes completed 1 hour of running. It is likely that differences in measurement technique, compressive loading, and dose of running explain differences in the magnitude of change in mean IVD height.

The exercise-induced reduction in IVD height and volume is likely to reflect increased hydrostatic pressure inside the disc and loss of fluid from the IVD. IVDs rely on diffusion and convection to exchange nutrients, and metabolic by-products with surrounding vasculature, and cyclical changes in intradiscal pressure are important to maintaining IVD health. Running training has been demonstrated to increase extracellular matrix production and cell proliferation in the lumbar IVD of rats.

At Dynamic Disc Designs, we have worked to bring you a dynamic intervertebral disc model to help spine professionals explain the compression and decompression of the spine. If patients have symptoms related to running, and you suspect its related to joint compression, consider using a dynamic disc model to help convey the compression biomechanics for effective patient education.

Dynamic Disc Designs and Jerome Fryer