Abstract: BACKGROUND: Studies have shown that long-term high-impact exercise stress can cause adaptive changes in the bones, which have certain effects on cortical bone thickness and trabecular bone density in athletes. Calcaneus bone density is often used as a basis for judging changes in bone mass.
OBJECTIVE: To measure the cortical thickness of the calcaneus and trabecular bone density and distribution trend in Taekwondo athletes, in order to provide reference for research on foot functional anatomy, imaging anatomy, foot movement biomechanics and ankle surgery. 
METHODS: Ten high-level Taekwondo athletes were enrolled as experimental group and nine ordinary sports enthusiasts as control group. The subjects in the two groups were all male, and there were no significant differences in height, weight and age. GE64-slice spiral CT was used to scan the subjects’ feet on both sides, and Mimics 21.0 software was used to measure the cortical thickness of the calcaneal tubercle, lateral process, and medial process as well as trabecular bone density. The length, width and height of the trabecular bone in the sagittal, horizontal and coronal image windows were measured. 
RESULTS AND CONCLUSION: The thickness of the left and right calcaneal tuberosity and medial process in the experimental group was greater than that in the control group (P < 0.05). In the experimental group, the thickness of the cortical bone of the left lateral process, medial process and calcaneal tubercle was greater than that of the right lateral process, medial process and calcaneal tubercle (P < 0.05). The bone mineral density of the left and right lateral calcaneus and medial process of the experimental group was higher than that of the control group (P < 0.01). The length, width and height of the trabecula of the left and right calcaneus (sagittal, horizontal and coronal planes) in the experimental group were larger than those in the control group (P < 0.05). Taekwondo strikes and jumps produce the stress and traction of the Achilles tendon and plantar muscle ligament, which can increase the cortical thickness of the calcaneus, increase the density of the trabecular bone, and change the shape of the trabecular bone, manifested by the increase in trabecular length, width and height, indicating that the cortical bone and trabecular bone of the calcaneus at force part have undergone adaptive changes, and the left and right feet have changed.

Key words: taekwondo, calcaneus, bony cortex, trabecular bone, stress, CT image