It has been suggested that blood circulation within the tendons contributes to repair of the tendon after the exercises. Recently, blood circulation of human tendons could be measured using red laser lights (Kubo et al. 2008b). Using this technique, we were able to measure changes in blood volume and oxygen saturation of human tendons by various treatments. During a 60-min heating, the blood volume and oxygen saturation of the tendon increased significantly from the resting level, and continued to increase by 35 min. These changes in blood circulation of tendon were considerably different from the temperatures of muscle and skin. Furthermore, when the needle tip was moved up and down from the targeted depth (up-and-down manipulation) at approximately 1 mm amplitude, the blood volume and oxygen saturation of the treated tendon increased significantly. After the removal of the acupuncture needle, the blood volume and oxygen saturation of the tendon increased gradually for the non-treated side. These results suggested that the change in blood circulation of the tendon during acupuncture with up-and-down manipulation was caused by axon reflex, and increase in blood flow in the tendons after the needle removal might be caused through the central nervous system. It is well known that heating and acupuncture treatments were quite effective in the management of tendon injuries. Therefore, these phenomena would be related to the changes in blood circulation of tendons due to heating and acupuncture treatments.
Keywords: Acupuncture; Blood volume; Heating; Oxygen saturation; Tendon injury.