Association between long-term exercise loading and lumbar spine trabecular bone score (TBS) in different exercise loading groups

OBJECTIVE To examine whether different exercise loading is associated with lumbar vertebral texture as assessed with Trabecular Bone Score (TBS). METHODS Data from 88 Finnish female athletes and 19 habitually active women (reference group) were analyzed. Participants' mean age was 24.3 years (range 17-40 years). Athletes were divided into five specific exercise loading groups according to sport-specific training history: high-impact (triple jumpers and high jumpers), odd-impact (soccer players and squash players), high-magnitude (power lifters), repetitive impact (endurance runners), and repetitive non-impact (swimmers). TBS-values were determined from lumbar vertebral L1-L4 DXA images. Body weight and height, fat-%, lean mass, isometric maximal leg press force, dynamic peak jumping force and lumbar BMD were also measured. RESULTS Endurance runners' mean TBS value differed significantly from all other groups being about 6% lower than in the reference group. After controlling for body height, isometric leg press force and fat-%, the variables found consistently explaining TBS, the observed between-group difference remained significant (B=-0.072, p=0.020). After controlling for BMD, the difference persisted (B=-0.065, p=0.016). There were no other significant adjusted between-group differences. CONCLUSION Exercise loading history comprising several repeated moderate impacts is associated with somewhat lower TBS, which may indicate specific lumbar microarchitecture in endurance runners.