Context: Running is one of the most popular sports worldwide. However, controversies exist regarding how running affects runner’s intervertebral discs (IVD). Objective: The purpose of this study was to systematically review studies that evaluated IVD morphology or composition changes in response to running exercise, to determine the impact of running exercise on IVD. Data Sources: A systematic literature search was performed for 4 major databases: PubMed, Cochrane, Embase, and Web of Science. Study Selection: Inclusion criteria were as follows: (1) healthy people without known IVD disease or major complications such as tuberculosis (IVD degeneration or low back pain are considered as minor complications); (2) subjects performed 1-time or regular running exercises; (3) pre and post comparison of runners or comparison between runners and healthy control subjects; (4) direct or indirect IVD morphology or composition measured; (5) IVD assessed before and after either acute or chronic running exercise, or compared cross-sectionally between runners and controls. Exclusion criteria were as follows: (1) reviews, editorials, letters or abstracts only; (2) animal studies; (3) subjects performed exercise other than running. Study Design: Systematic review. Level of Evidence: Level 3. Data Extraction: The extracted data included study design and primary outcomes of the included studies. The Newcastle-Ottawa scale (NOS) was used to evaluate study quality and risk of bias. Results: A total of 13 studies with 632 participants were included in the final analysis; 4 studies measured IVD changes using stature or spinal height, and the other 9 measured IVD changes using magnetic resonance imaging; 6 studies found that running acutely and negatively impacts IVD; 3 out of 5 cross-sectional studies found that IVD parameters are better for runners than controls; 1 longitudinal study found no significant difference in IVD before and after training for marathon in runners; 1 longitudinal study found no significant difference in changes of IVD between runners and controls after 15 years of follow-up. Conclusion: Negative changes in IVD exist for a short period of time after running, which may be due to the temporary compression pushing water content out of the disc. Cross-sectional studies suggest that long-term running exerts a mild positive effect on IVD; however, this inference has not been confirmed by high-quality longitudinal studies.

Objective: To assess the reliability and reproducibility of using a four arterial occlusions protocol and near-infrared spectroscopy (NIRS) to measure resting and post-exercise muscle oxidative metabolism (mVO ₂ ). Approach: mVO ₂ was measured on the forearm muscles on two different days (day1 and day2) within one week in 11 healthy young adults (24.2 ± 2.7 years; 5 males). mVO ₂ was measured using NIRS during four repeated arterial occlusions at rest, and 5 min after exercise consisting of 90 s of rapid concentric contractions (5 minEPOC). Main results: Resting mVO ₂ with four measurements was 17.88 ± 3.04% min ⁻¹ on day 1 and 19.42 ± 3.03% min ⁻¹ on day 2 ( p = 0.171) with a coefficient of variation (CV) of 10.1%. When using only the first measurement, the CV increased to 18.5% ( p = 0.039). 5minEPOC was 212.4 ± 142.5% and 177.1 ± 125.8% higher than resting and was not different between days one and two (53.83 ± 21.17% min ⁻¹ and 52.22 ± 22.10% min ⁻¹ , respectively, p = 0.199). The CV and intraclass correlation (ICC) for 5minEPOC between days one and two were, 6.5% and 0.98, respectively. Using only the first value for 5minEPOC resulted in slightly higher CV but similar ICC (7.6% and 0.98, respectively; both p > 0.05). Significance: Our results suggest that within a single testing session, one arterial occlusion can provide reproducible measurements for both resting and post-exercise mVO ₂ similar to that of a four arterial occlusions protocol. While a four arterial occlusion protocol provides similar reliability for post-exercise mVO ₂ with one arterial occlusion, it reduces the day-to-day variance for resting mVO ₂ and therefore should be employed for longitudinal studies.

Excess bone marrow adiposity may have a negative effect on bone growth and development. The aim of this study was to determine whether a procedure using standard T1-weighted magnetic resonance images provides an accurate estimate of bone marrow fat in children with typical development and in children with mild spastic cerebral palsy (CP; n = 15/group; 4–11 y). Magnetic resonance imaging was used to acquire T1-weighted images. It was also used to acquire fat and water images using an iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) technique. Bone marrow fat volume and fat fraction in the middle-third of the tibia were determined using the standard T1-weighted images (BMFV_T1 and BMFF_T1, respectively) and the fat and water images (BMFV_IDEAL and BMFF_IDEAL, respectively). In both groups, BMFV_T1 was highly correlated with (both r > 0.99, p < 0.001) and not different from (both p > 0.05) BMFV_IDEAL. In both groups, BMFF_T1 was moderately correlated with (both r = 0.71, p < 0.01) and not different from (both p > 0.05) BMFF_IDEAL. There was no group difference in BMFV_T1 or BMFV_IDEAL (both p > 0.05). BMFF_IDEAL was higher in children with CP (p < 0.05), but there was no group difference in BMFF_T1 (p > 0.05). We conclude that a procedure using standard T1-weighted magnetic resonance images can produce estimates of bone marrow fat volume similar to estimates from the IDEAL technique in children. However, it is less sensitive to variation in the bone marrow fat fraction.