In addition to the histological study of tendon blood circulation, high level of resting blood flows have been functionally observed in the in-vivo tendon tissue preparation. Interest has been directed to investigate the phenomenon from the measurement of tendon tissue Po2 changes which may indicate the activity of capillary blood flow. Simultaneous measurements were done in tendon synovial fluid, tendon and muscle tissues of the 15 rabbit hindlimbs, in conditions of hypoxia and hyperoxia. Continuous measurements of tissue Po₂ were performed by polarographic method using a pair of the wire platinum electrode (80μm in diameter) with polymer membrane to the indifferent silver electrode. Average Po₂ of tendon synovial fluid, tendon fiber and muscle tissues at rest (mean±SD, n) were 37.36±24.32 (10), 30.96±14.72 (10) and 19.54±8.05 (8), respectively. These data increased gradually to the maximal level of 45.46±27.46 (10), 39.23±16.23 (10) and 25.96±9.77 (8) after cutting of sciatic nerve. Reactive hyperemia-like Po₂ increase immediately after release of femoral arterial occlusion was observed neither in tendon synovial fluid nor in tendon tissue. There was no significant difference between each other of tissues in the process of Po₂ increase during oxygen intake and the decrease after cessation of oxygen flushing. During exercise, a marked decrease of Po2 was obtained in muscle, but not in tendon synovial fluid.
These data indicate that high level of Po₂ in tendon and the surrounding tissuse may have some oxygen supply channels including segmental blood supply system with a short length of and/or a large size of capillary.

A study was designed to determine the effect of cooling down and massage on lower leg volume after heel-raising exercise in men. The subjects were six healthy athletes ranging in age from 18 to 23 years. Lower leg volume was measured at rest and after heel-raising exercise using Lundvall's volumetric method with a water-filled“boot”. Ten minutes of rhythmic heel-raising, performed at 45 times per minute, was monitored continuously using a mech-anograph.
Immediately after the end of exercise, each subject lay in a relaxed supine position and the leg was raised to 45 degrees. A cuff was then attached around the thigh, and the cuff pressure was increased to occlude the leg circulation. The leg volume was then determined in a standing position. After the first measurement of the lower leg, three kinds of treatment were applied for each subject (no treatment, one minute walking : total seven minutes, one minute massage : total five minutes) .
The results obtained were as follows ;
1) The slopes of the recovery curve of lower leg volume were more gentle with no treatment than with cooling down and massage.
2) The time constant (min) obtained from the decreasing curve of lower leg volume after heel-raising exercise was 10.2 for no treatment, 9.4 for cooling down and 6.4 for massage.
3) The total fluid accumulation volume in the lower leg (ml/l lower leg) following heel-raising exercise was 450.9 for no treatment, 288.9 for cooling down and 198.6 for massage.
It is suggested that such a disappearance of fluid accumulation in exercising muscles of the lower leg following cooling down and massage is due to a mechanical pump action against the surrouding local skeletal muscle tissues.

Evidence of an increased resting blood flow in the tendon against the adjacent muscle was confirmed in the in situ hindlimb preparation of a rabbit anesthetized with urethane. The tendon tissue blood flow was found to be modulated by nervous and mechanical factors. The effect of nervous control was demonstrated by the denervation of the sciatic nerve, which showed a gradual increase in the resting blood flow in the tendon and muscle after being severed. During local muscle exercise, the increase of tendon tissue blood flow observed was minimal in comparison with the adjacent muscle. The tendon surrounding tissue blood flow showed site-dependent characteristics along the longitudinal tendon bundles. Evidence of tendon vascular structure in the rabbit species was confirmed by observing capillaries in cross sectional fascicles and longitudinal and transversal vessels in the paratenon of the Achilles tendon. These results strongly suggest a physiological model of local tissue temperature regulation and fluid dynamics in the biological system.

In this study, we performed echo intensity obtained from ultrasonographic images was used as a reference for intramuscular fat mass to determine whether intramuscular fat can be estimated non-invasively using the bioelectrical impedance method. The subjects were 45 healthy male university students (mean age 20.2±1.4 years) of the athletic club. An ultrasound images were taken from vastus lateralis, and the echo intensity was calculated from the obtained image using image analysis software. The impedance corresponding to each of the 17 points from 4to 700 kHz were collected using a multi-frequency impedance measuring device. In addition, intracellular resistance and extracellular resistance were calculated using Cole-Cole distribution model. Pearson’s correlation coefficient was used for the relationship between echo intensity and impedance. As a result, when using a frequency of 50 kHz or more, we observed a moderate correlation (r=0.529 ~ 0.597, p<0.001) between an impedance of 2cm at the distance between the sensing (V) and current (I) electrodes and echo intensity at 2cm from the skin surface. A moderate correlation (r=0.551, p<0.001) was observed between the intracellular resistance at the V-I electrode spacing of 2cm and echo intensity at 2cm form the skin surface. However, there was only a weak correlation between extracellular resistance and echo intensity. This suggests that the impedance and intracellular resistance measured at a frequency of 50 kHz or higher and with a V-I electrode spacing of 2cm reflect intramuscular fat.