title: Unchanged muscle deoxygenation heterogeneity during bicycle exercise after 6 weeks of endurance training.
abstract: The purpose of this study was to examine the changes in muscle oxygen saturation (SmO(2)) level and its heterogeneity after 6 weeks of endurance training using multi-channel near infrared spatially resolved spectroscopy (NIR(SRS)). 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 NIR(SRS) 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(O)(2peak) and increased every 5%V(O)(2peak) when the subjects could maintain the work rate three times consecutively. After training, V(O)(2peak) 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 SmO(2) within measurement sites at was significantly decreased (Pre: 56.1 +/- 1.1 %, Post: 53.3 +/- 2.2 %, p < 0.05). Conversely, the heterogeneity of the SmO(2) during exercise was not changed by training. These results suggest that the functional heterogeneity of O(2) balance did not change due to endurance training, and the O(2) balance heterogeneity may not interfere with O(2) exchange in the activating muscle in healthy individuals.
authors.affiliation: Department of Sports Medicine for Health Promotion, Tokyo Medical University, Tokyo 160-8402, Japan. kime@tokyo-med.ac.jp
authors.forename: Ryotaro
authors.initials: R
authors.lastname: Kime
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Niwayama
authors.forename: Masako
authors.initials: M
authors.lastname: Fujioka
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Shiroishi
authors.forename: Takuya
authors.initials: T
authors.lastname: Osawa
authors.forename: Kousuke
authors.initials: K
authors.lastname: Shimomura
authors.forename: Takuya
authors.initials: T
authors.lastname: Osada
authors.forename: Norio
authors.initials: N
authors.lastname: Murase
authors.forename: Toshihito
authors.initials: T
authors.lastname: Katsumura
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D009132:Muscles / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance; D019265:Spectroscopy, Near-Infrared; D013997:Time Factors
chemical_list: D010100:Oxygen