title: Comparison of muscle O(2) dynamics at different sites of the forearm flexor muscles during incremental handgrip exercise.
abstract: This study investigated heterogeneity of muscle O(2) consumption (diffusive m-VO(2)) and muscle oxygenation difference (m-O(2) difference) within the forearm flexor muscles using multi-optical fibers near-infrared continuous wave spectroscopy (NIRcws) during incremental exercise. Nine healthy male subjects performed incremental dynamic handgrip exercise until exhaustion. The workload was increased by 5% maximal voluntary contraction (MVC) every 1 min, starting at 10% MVC. The NIRcws probes (10 channels) were placed on the right forearm flexor muscles to monitor muscle oxygenation. The diffusive m-VO(2) and the m-O(2) difference were evaluated at each exercise stage. The diffusive m-VO(2) at the medial site was significantly greater than the lateral site at 25% MVC (p < 0.05). Similarly, m-O(2) difference at the medial site increased significantly over the lateral site (p < 0.05), whereas there were no significant differences in diffusive m-VO(2) or m-O(2) difference between the proximal and distal sites. These results in forearm muscle were different from the previous study which found that there were longitudinal differences in muscle VO(2) in the femoral muscle.
authors.affiliation: Department of Sports Medicine for Health Promotion, Tokyo Medical University, Tokyo 160-8402, Japan. m-fuji@tokyo-med.ac.jp
authors.forename: Masako
authors.initials: M
authors.lastname: Fujioka
authors.forename: Ryotaro
authors.initials: R
authors.lastname: Kime
authors.forename: Shunsaku
authors.initials: S
authors.lastname: Koga
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; D004058:Diffusion; D005080:Exercise Test; D005542:Forearm / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D019265:Spectroscopy, Near-Infrared
chemical_list: D010100:Oxygen