Pattern of deoxygenation in vastus lateralis and rectus femoris muscles during a ramp-loaded cycling / 体力科学

The purpose of this study was to compare changes in oxygenation in the Vastus Lateralis (VL) and Rectus Femoris (RF) muscles during a ramp-loaded bicycle exercise. Twelve healthy males participated in the experiment. The test consisted of a leg arterial occlusion at rest and a ramp-loaded exercise (20 watts/min) using a bicycle ergometer until exhaustion. The changes in deoxygenation in each muscle was measured by near infrared spectrometer (NIRS) . The probes of NIRS were placed on VL and RF approximately 12 cm above the right knee. Oxy-Hb/Mb signals from NIRS were calculated as 100% at rest, with 0 % being the lowest value during the leg arterial occlusion. Pulmonary gas exchanges (VE, VO<SUB>2</SUB>, VCO<SUB>2</SUB>) were measured with an expiratory gas analyzer. In 10 subjects, muscle oxygenation level in VL decreased linearly until the deoxygenation limiting point (DOLP) -the point in exercise at which the deoxygenation rate decreases noticeably. However, in 2 subjects, the DOLP was not detected, and the muscle oxygenation level decreased linearly until exhaustion. The muscle oxygenation level in RF also decreased linearly until 70%VO<SUB>2</SUB>max, although the deoxygenation rate was smaller than that in VL. Thereafter, the muscle oxygenation level in RF continued to decrease until exhaustion. No DOLP was found in any subjects in RF. Compared with the muscle oxygenation level in RF at any points during the exercise, those in VL were lower until 90%VO<SUB>2</SUB>max (P<0.001) . However, the difference in muscle oxygenation levels between VL and RF at exhaustion was not noted. This study indicated that the patterns of deoxygenation in VL and RF during a ramploaded bicycle exercise were different.

Effects of middle-distance triathlon race on serum biochemical parameters / 体力科学

For the purpose of examining relative impact of the middle-distance triathlon race (Swim : 2.0 km, Bike : 90.0 km, Run : 21.0 km), blood samples were taken on the day before, immediately after, and the day following the race from triathletes who participated in a middle-distance triathlon race at Tokunoshima, Kagoshima in June 1993. White blood cell count was significantly increased immediately after the race.It was recovered on the next day to the value observed before the race. Serum creatine phosphokinase activity was elevated significantly immediately after the competition. It continued to rise up to the level of about 4 times higher than the pre-race value. In terms of renal function, serum creatinine concentration showed a significant increase immediately after the competition. However, it recovered to normal range by the day after the competition. In addition, serum urea nitrogen concentration was also significantly increased after the competition. It remained at the high level until the day after the competition. In conclusion, it might be suggested that the middle-distance triathlon gives a significant impact on human body, even though it is quntitatively less than the long-distance type (Swim : 3.9 km, Bike : 180.2 km, Run : 42.2 km) .