MUSCLE OXYGENATION HETEROGENEITY IN A SINGLE MUSCLE AT REST AND DURING BICYCLE EXERCISE / 体力科学

We evaluated regional differences of muscle O₂ dynamics between distal and proximal sites in the vastus lateralis (VL) muscle using near infrared spatial resolved spectroscopy (NIR_SRS). forty-one male subjects performed a 30 W ramp incremental bicycle exercise test until exhaustion. The NIR_SRS probes were attached on each distal and proximal site in the VL. The pulmonary O₂ uptake and heart rate were monitored continuously during the experiment. The TOI at rest was significantly higher in proximal than distal sites (65.0±5.2 vs. 69.7±4.6%, p<0.001). The TOI at exhaustion was also significantly higher in proximal than distal sites (39.5±6.7 vs. 47.5±7.6%, p<0.001). Moreover, a significant correlation was found between VO₂max and the TOI at exhaustion in each proximal and distal site in the VL. Half time reoxygenation, the time to reach a value of half-maximal recovery, was significantly slower in distal sites than proximal sites (27.1±5.6 vs. 25.0±6.1 sec, p<0.01). In conclusion, lower muscle oxygenation at exhaustion in higher VO₂max may be due to enhanced O₂ extraction in high oxidative capacity muscle. In addition, slower reoxygenation and lower muscle deoxygenation at the distal site in the VL may be explained by differences in O₂ supply and/or muscle fiber composition between distal and proximal sites.

EFFECTS OF BICYCLE ERGOMETER EXERCISE AND PGE₁ INJECTION FOR PATIENTS WITH INTERMITTENT CLAUDICATION / 体力科学

The purpose of this study was to clarify the effects of bicycle ergometer training and prostaglandin E₁ (PGE₁) for patients with intermittent claudication. Subjects were divided into four groups : the medication group (M), the PGE₁ group (P), the exercise group (E) and the PGE₁ and exercise group (PE). The P group was injected with 10<i>μ</i>g of PGE₁, the E group performed bicycle ergometer exercise 3 times a week for 6 weeks, and the PE group was injected with PGE₁ and performed exercises. The maximal walking distance (MWD) was evaluated by a treadmill test. Muscle oxygenation level was measured by near-infrared spectroscopy and recovery half time (T_1/2) was calculated. MWD was significantly improved for P (142%), E (216%) and PE (240%) groups. T_1/2 was significantly improved in the E and PE groups. This study indicates that improvement of MWD was a result of development of muscle perfusion in lower limbs and PGE₁ injection may support exercise therapy.