title: Relationship between muscle oxygenation and electromyography activity during sustained isometric contraction.
abstract: The purpose of this study was to clarify the relationship between electromyography (EMG) spectrum changes and muscle oxygenation measured by near-infrared time-resolved spectroscopy (TRS). Each subject performed sustained isometric knee extension at 50% of the maximal voluntary contraction load for 1 min. Surface EMG and TRS were simultaneously recorded from the right vastus lateralis muscle. Mean power frequency (MPF) of the power spectrum was calculated every 5 s during isometric contraction using fast Fourier transform, and decrease in the slope of MPF for 1 min was calculated using the least squares method. The maximal changes in oxygenated haemoglobin and myoglobin (Oxy Hb/Mb) and in deoxygenated haemoglobin and myoglobin (Deoxy Hb/Mb) from pre-contraction values of 1 min were calculated. There were significant relationships between the decrease in the slope of MPF and the maximal changes in Oxy Hb/Mb and Deoxy Hb/Mb (P < 0.05). These findings suggested that changes in Oxy Hb/Mb and Deoxy Hb/Mb indicate muscle fatigue assessed by EMG.
authors: Department of Rehabilitation, Faculty of Medicine, Kagawa University Hospital, Miki-cho, Kita-gun, Kagawa, Japan.
authors: Eiji
authors: E
authors: Yamada
authors: Takashi
authors: T
authors: Kusaka
authors: Nobuo
authors: N
authors: Arima
authors: Kenichi
authors: K
authors: Isobe
authors: Tetsuji
authors: T
authors: Yamamoto
authors: Susumu
authors: S
authors: Itoh
mesh_terms: D000328:Adult; D004576:Electromyography; D015444:Exercise; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D007717:Knee; D008297:Male; D009119:Muscle Contraction; D018763:Muscle Fatigue; D009211:Myoglobin / Q000378:metabolism*; D010101:Oxygen Consumption; D010108:Oxyhemoglobins / Q000378:metabolism*; D052097:Quadriceps Muscle / Q000502:physiology*; D019265:Spectroscopy, Near-Infrared
chemical_list: D009211:Myoglobin; D010108:Oxyhemoglobins; C017595:oxymyoglobin