Unchanged muscle deoxygenation heterogeneity during bicycle exercise after 6 weeks of endurance training
The purpose of this study was to examine the changes in muscle oxygen saturation (SmO2) level and its heterogeneity after 6 weeks of endurance training using multi-channel near infrared spatially resolved spectroscopy (NIRSRS). Nine healthy subjects participated in this study (Male = 6, Female = 3, age: 27 ∼ 5 years, height: 168.7 ∼ 7.4 cm, weight: 62.4 ∼ 12.4 kg). The subjects performed a 30 W ramp incremental bicycle exercise test until exhaustion before and after endurance training. The NIRSRS probe was attached to the left vastus lateralis muscle along the direction of the long axis. The subjects performed bicycle exercise for 30 min/day, 3 days/week for 6 weeks. The work rate during training was set at 60%V- O2peak and increased every 5%V- O2peak when the subjects could maintain the work rate three times consecutively. After training, . VO2peak was significantly increased (Pre: 42.7 ∼ 9.9 ml/kg/min, Post: 52.3 ∼ 7.2 ml/kg/min, p < 0.001) and the mean SmO2 within measurement sites at V- O2peak was significantly decreased (Pre: 56.1 ∼ 1.1 %, Post: 53.3 ∼ 2.2 %, p < 0.05). Conversely, the heterogeneity of the SmO2 during exercise was not changed by training. These results suggest that the functional heterogeneity of O2 balance did not change due to endurance training, and the O2 balance heterogeneity may not interfere with O2 exchange in the activating muscle in healthy individuals. © Springer Science+Business Media, LLC 2010.
Kime, R; Niwayama, M; Fujioka, M; Shiroishi, K; Osawa, T; Shimomura, K; Osada, T; Murase, N; Katsumura, T
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