Changes in blood circulation of the contralateral Achilles tendon during and after acupuncture and heating.

The purpose of this study was to investigate the effects of acupuncture and heating (application of hot pack) treatments on blood circulation in the contralateral Achilles tendon. During the treatments (10 min for acupuncture, 20 min for heating) and recovery period (40 min), the blood volume (THb) and oxygen saturation (StO2) of the treated and the non-treated tendons were measured using red laser lights. During both treatments, THb and StO2 of the treated tendon increased significantly from the resting level. The increased THb and StO2 of the treated tendon were maintained until the end of the recovery period after removal of the acupuncture needle, although these values decreased after removal of the hot pack. Although THb of the non-treated sides did not change during both acupuncture and heating treatments, it increased gradually after removal of the acupuncture needle or the hot pack. For both treatments, the amount of increase in THb of the non-treated tendon was significantly correlated to that of the treated tendon during the last phase of recovery period. These results obtained from the healthy subjects imply that blood circulation in the injured tendon in a plaster cast may be improved by applying acupuncture or heating treatments to the contralateral healthy limb.

Noninvasive measures of blood volume and oxygen saturation of human Achilles tendon by red laser lights.

AIM: Spectroscopic measurement using near-infrared spectroscopy and red laser lights was performed to investigate the blood volume (total haemoglobin; THb) and oxygen saturation (oxygenated haemoglobin saturation; StO2) of the human Achilles tendon during single and repetitive isometric contractions. METHODS: Twelve men performed isometric plantar flexion exercises at intensities of 10% (3 min), 30% (2 min), 50% (1 min) and 70% (30 s) of the maximum voluntary contraction (MVC). In addition, they performed 50 repetitions at 70% of the MVC with 5-s contractions and a 5-s gap between repetitions for 10 min. The probes were positioned on the Achilles tendon and medial gastrocnemius muscle. RESULTS: THb and StO2 of the Achilles tendon decreased during 'single' contraction at all force levels. On the other hand, after the end of the repetitive exercises, THb and StO2 of the Achilles tendon increased gradually, and remained at this level until the end of the recovery period. CONCLUSION: The blood volume and oxygen saturation within the human Achilles tendon increased after the 'repetitive' muscle contractions, while they decreased after the 'single' contraction. Furthermore, the increases in blood volume and oxygen saturation within the tendon after repetitive contractions may be related to tendon repair after exercises involving mechanical loading of the tendon.