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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 19yrs) and 71 non‐athletic 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 MRI. 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≤0.029), swimming (P≤0.010), soccer (P=0.036) and baseball (P=0.011) with greater IVD nucleus hydration in soccer (P=0.007). After matching participants based on back‐pain status and body height, basketball players showed evidence of IVD hypertrophy (P≤0.043) and soccer players greater IVD nucleus hydration (P=0.001) than referents. Greater career duration and training volume correlated with less (i.e. 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. peerReviewed

Purpose Cycling is widely practiced as a mode of transportation, a leisurely pursuit, and a competitive sport. Approximately half of cyclists experience low back pain. Yet, there has been limited study of spine tissue adaptations due to cycling.Methods To investigate potential risk factors for spinal pain, we compared 18 high-volume cyclists (>150 kmwk(-1) for 5 yr) to 18 height-matched nonsporting referents. Participants had no history of spinal pathology. Magnetic resonance imaging was used to quantify intervertebral disc (IVD) morphology and hydration, and psoas, erector spinae, quadratus lumborum, and multifidus muscle size and fat content. Endurance of trunk muscles (flexors and extensors) was measured, and physical activity levels were assessed objectively using accelerometry.Results Cyclists' IVD showed prolonged T2 time (+10.0% 17.3%; P = 0.021), implying better IVD hydration and glycosaminoglycan content, compared with referents. Lower thoracic and upper lumbar IVD T2 time were longer in cyclists (P 0.029) but not at the lower lumbar spine. T2 time differences were larger in the nucleus pulposus compared with the annulus fibrosus. Cyclists showed larger psoas muscles with less fat content compared with referents. Cyclists also exhibited longer isometric trunk endurance times (P 0.036) and higher physical activity levels (osteogenic index, P = 0.038).Conclusion Despite previous studies reporting higher than average prevalence of back pain in cyclists, the high-volume road cyclists in our cohort showed no anatomical or functional deficiency in spinal structures. By contrast, we found evidence for beneficial adaptations to the IVD and psoas muscles in high-volume cyclists compared with referents. These data support the notion that cycling is not detrimental to the spine, rather, by contrast, may be associated with beneficial changes at the spine. Refereed/Peer-reviewed