Characterization of bone formation by dynamic histomorphometry. (a) Micro-CT images of caudalvertebral bodies display the regions of interest (ROI) including the vertebral body end plates. (b) Fluorescencemicroscopy reveals fluorescent labeling in the end plates from both zebrafish groups. Larger inter-label distancecan be observed in exercised zebrafish indicating higher bone formation activity. (c) Mineralized surface perbone surface (MS/BS) was significantly higher in the exercise group. (d) Mineral apposition rate (MAR) did notvary significantly between groups. (e) Bone formation rate (BFR) was significantly higher in exercised zebrafish.The increased deposition of new bone in the end plates of exercised zebrafish explains the increased vertebrallength, bone volume and tissue volume measured using micro-CT (see Fig. 3).