Ayumi Sakamoto

Relationship between reduced lower abdominal blood flows and heart rate in recovery following cycling exercise

Aim:  To examine the blood flow (BF) response in the lower abdomen (LAB) in recovery following upright cycling exercise at three levels of relative maximum pulmonary oxygen consumption () and the relationship of BFLAB to heart rate (HR) and target intensity.

The Relationship between Physical Fitness and Coronary Risk Factor Profiles in Japanese Women

The purpose of this study was to investigate the relationship between physical fitness and coronary risk factor profiles in Japanese women. The subjects were 1,483 women (ages 30 to 69) who participated in a practical health promotion program. After medical examination, physical fitness was evaluated by conducting a symptom limited maximal exercise test by ergometer to measure maximum oxygen uptake (peakVO2) with an expired gas analyzer. The subjects were classified into 3 groups (high fitness, moderate fitness, and low fitness) according to age and physical fitness level. The results showed that the subjects in higher fitness groups had lower levels in: body mass index (BMI), percentage of body fat, waist-hip ratio, resting blood pressure, and atherogenic index, and higher HDL-cholesterol compared to those in lower fitness group. Even after adjustment for the effects of age and BMI, die subjects in the higher fitness groups had better coronary risk factor profiles. These results suggest that among Japanese women a high level of physical fitness is related to favorable coronary risk factor profiles.

Regional Differences in Muscle Energy Metabolism in Human Muscle by 31P-Chemical Shift Imaging

Previous studies have reported significant region-dependent differences in the fiber-type composition of human skeletal muscle. It is therefore hypothesized that there is a difference between the deep and superficial parts of muscle energy metabolism during exercise. We hypothesized that the inorganic phosphate (Pi)/phosphocreatine (PCr) ratio of the superficial parts would be higher, compared with the deep parts, as the work rate increases, because the muscle fiber-type composition of the fast-type may be greater in the superficial parts compared with the deep parts. This study used two-dimensional 31Phosphorus Chemical Shift Imaging (31P-CSI) to detect differences between the deep and superficial parts of the human leg muscles during dynamic knee extension exercise. Six healthy men participated in this study (age 27±1 year, height 169.4±4.1 cm, weight 65.9±8.4 kg). The experiments were carried out with a 1.5-T superconducting magnet with a 5-in. diameter circular surface coil. The subjects performed dynamic one-legged knee extension exercise in the prone position, with the transmit-receive coil placed under the right quadriceps muscles in the magnet. The subjects pulled down an elastic rubber band attached to the ankle at a frequency of 0.25, 0.5 and 1 Hz for 320 s each. The intracellular pH (pHi) was calculated from the median chemical shift of the Pi peak relative to PCr. No significant difference in Pi/PCr was observed between the deep and the superficial parts of the quadriceps muscles at rest. The Pi/PCr of the superficial parts was not significantly increased with increasing work rate. Compared with the superficial areas, the Pi/PCr of the deep parts was significantly higher (p<0.05) at 1 Hz. The pHi showed no significant difference between the two parts. These results suggest that muscle oxidative metabolism is different between deep and superficial parts of quadriceps muscles during dynamic exercise.

Regional Differences of Metabolic Response During Dynamic Incremental Exercise by 31 P-CSI

The aim of this study was to detect the differences in muscle metabolic response of the quadriceps during incremental dynamic knee exercise using regional (31)Phosphorus Chemical Shift Imaging ((31)P-CSI). Sixteen healthy men participated in this study (age 28 ± 5 years, height 171.4 ± 3.9 cm, weight 67.1 ± 9.8 kg). The experiments were carried out with a 1.5-T superconducting magnet with a 5-in. diameter circular surface coil. The subjects performed isometric unilateral knee extension exercise to detect their maximum voluntary contraction (MVC) in prone position. Then they performed dynamic unilateral knee extension exercise in the magnet at 10, 20, 30 and 40 % of their MVC with the transmit-receive coil placed under the right quadriceps. The subjects pulled down a rope with the adjusted weight attached to the ankle at a frequency of 0.5 Hz for 380 s. Intracellular pH (pHi) was calculated from the median chemical shift of the inorganic phosphate (Pi) peak relative to phosphocreatine (PCr). The quadriceps were divided into three regions, (1) medial, (2) anterior, (3) lateral, and in comparison, there was no significant difference in Pi/PCr nor in pHi between regions, except Pi/PCr of the medial region was significantly higher than the anterior region at maximum intensity (p < 0.05). These results suggest that regional muscle metabolic response is similar in the quadriceps except at maximum intensity.

Effects of Acupuncture Stimulation on Muscle Tissue Oxygenation at Different Points

Muscle tissue oxygenation is a critical issue in muscle complications such as pain, exhaustion, stiffness, or fatigue during and after exercise. The aim of this study was to investigate whether the changes of muscle tissue oxygenation could be observed at both erector spinae muscle at S1 level and gastrocnemius during and after acupuncture stimulation to ipsilateral erector spinae at S1 level. The subjects were ten healthy males. Muscle oxygenation was monitored by near infrared spectroscopy (NIRS), and the probes were placed on the right side of the erector spinae muscle at S1 level (Guanyuanshu, BL26) and the belly of the gastrocnemius on the right (Chengjin, BL56). The subjects lay on the bed in prone position for 10 min, followed by acupuncture insertion into the right side of BL26. The needle was left for 10 min and subjects were kept still for 10 min after removal. At BL26, oxygenated-hemoglobin (oxy-Hb) was significantly increased compared to the baseline at 10 min after insertion (p < 0.05), then continued increasing. Total hemoglobin (t-Hb) was increased at 2 min after removal (p < 0.05). Tissue-oxygen saturation (StO2) was increased at 7 min after insertion (p < 0.05). At BL56, oxy-Hb and t-Hb were increased at 6 and 2 min after removal, respectively (p < 0.05). StO2 showed no significant change. The acupuncture stimulation affected muscle tissue oxygenation differently at both stimulated and non-stimulated points in the same innervation.

P01.21. Effect of acupuncture on isotonic contraction of elbow flexor

Methods Subjects are 20 healthy males. Maximum Voluntary Contraction (MVC) of elbow flexor was measured using a strain gauge prior to exercise (MVC1). Subjects received acupuncture stimulation before the exercise on their biceps brachii. The stimulation is either deep needling (targeting muscle; mACU) or superficial needling (sACU). The exercise protocol contains 5 sets * 10 repetitions of maximum contraction of elbow flexion at 50% MVC and 90 second intervals between sets. After the exercise subjects were measured for their MVC again (MVC2). The muscle power and the velocity of every contraction was measured using a dynamometer. Electromyogram (EMG) and muscle blood flow (MBF) were also observed during the exercise. Subjects did the same exercise and we measured the same parameter without any stimulation as control. The decrease of MVC between MVC1 and MVC2, muscle power and velocity among sets and repetitions were evaluated.

The Effect of Acupuncture on Muscle Blood Volume and Oxygenation

A considerable number of patients (61.5/1000) who complain of shoulder stiffness visit oriental therapeutic clinics (Journal of Health and Welfare Statistics, 2007). Several studies have shown that acupuncture can be a useful modality for treating pain due to muscle spasms (Lundeberg et al., 1988: Sandberg et al., 2005: Inoue et al., 2006). It is believed that shoulder stiffness is caused primarily by restriction of blood flow to the working muscles where accumulated metabolites appear to activate sympathetic vasoconstrictors. Acupuncture stimulation (AS) is reported to increase local tissue blood flow in animals (Noguchi et al., 1999; Sato et al., 2000; Uchida et al., 2007) and humans (Sakai 2005; Sandberg et al., 2003; Sandberg et al., 2005) and are applicable in therapeutic interventions of shoulder stiffness. The effects of acupuncture include neural, endocrinological, cardiovascular, and immunological functions. Among cardiovascular effects, in particular, acupuncture stimulation elicits enhanced muscle blood flow via peripheral vasodilatation. The enhanced blood flow response induced by acupuncture may be attributable to C-fibre mediated axon reflex (Nishijo et al., 1997) resulting from noxious mechanical stimulation. Conventional invasive techniques for evaluating muscle blood flow have limitations such as a relatively great burden on subjects and tissue destruction that may influence blood flow itself. On the other hands, noninvasive methodologies such as laser Doppler flowmetry and thermography could primarily measure and evaluate superficial skin blood flow response. In vivo near-infrared spectroscopy (NIRS) is a noninvasive technology for measuring muscle blood volume and oxygenation response with a depth of ~2cm from the skin surface (Hamaoka et al., 2007), which is suitable for assessing the effect of acupuncture on deep tissue blood flow and metabolic response. First, we documented in the section 2.1 whether AS would provoke vasodilatation in the trapezius muscle and whether the influence of AS would propagate to a region distant from the stimulation point (spatial distribution of the stimulation). Further, the temporal response at the stimulation onset was also examined. In the section 2.2, we reported the trapezius muscle blood volume and oxygenation in the stimulation region during four different acupuncture techniques, which are popular intervention techniques in Japan.