Mechanical loading influences the lumbar intervertebral disc. A cross-sectional study in 308 athletes and 71 controls

There is evidence in animal populations that loading and exercise can positively impact the intervertebral disc (IVD). However, there is a paucity of information in humans. We examined the lumbar IVDs in 308 young athletes across six sporting groups (baseball, swimming, basketball, kendo, soccer, and running; mean age 19 years) and 71 nonathletic controls. IVD status was quantified via the ratio of IVD to vertebral body height (IVD hypertrophy) and ratio of signal intensity in the nucleus to that in the annulus signal (IVD nucleus hydration) on sagittal T2-weighted magnetic resonance imaging. P values were adjusted via the false discovery rate method to mitigate false positives. In examining the whole collective, compared to referents, there was evidence of IVD hypertrophy in basketball (P ≤ .029), swimming (P ≤ .010), soccer (P = .036), and baseball (P = .011) with greater IVD nucleus hydration in soccer (P = .007). After matching participants based on back-pain status and body height, basketball players showed evidence of IVD hypertrophy (P ≤ .043) and soccer players greater IVD nucleus hydration (P = .001) than referents. Greater career duration and training volume correlated with less (ie, worse) IVD nucleus hydration, but explained less than 1% of the variance in this parameter. In this young collective, increasing age was associated with increased IVD height. The findings suggest that basketball and soccer may be associated with beneficial adaptations in the IVDs in young athletes. In line with evidence on other tissues, such as muscle and bone, the current study adds to evidence that specific loading types may beneficially modulate lumbar IVD properties.