Affiliations: [a] Department of Rehabilitation, Kagawa Medical
University Hospital, Kagawa, Japan | [b] Maternal Perinatal Center, Kagawa Medical University
Hospital, Kagawa, Japan | [c] Department of Orthopedic Surgery, Kagawa Medical
University, Kagawa, Japan | [d] Department of Pediatrics, Kagawa Medical University,
Kagawa, Japan
Note: [] Address for correspondence: Eiji Yamada, Department of
Rehabilitation, Kagawa Medical University Hospital, 1750-1 Ikenobe, Miki-cho,
Kita-gun, Kagawa 761-0793, Japan. Tel.: +81 87 891 2306; Fax: +81 87 891 2307;
E-mail: yamada@kms.ac.jp
Abstract: The purpose of this study was to investigate the relationships of
muscle oxygenation determined by using near-infrared spectroscopy with muscle
force and electromyography during isometric contraction in ten healthy males.
The subjects performed sustained isometric extension at 30%, 50% and 70% of
the maximal voluntary contraction (MVC) for 10 seconds, respectively.
Near-infrared spectroscopy and surface electromyography were simultaneously
recorded from the right vastus medialis muscle. The rate of decrease in muscle
oxygenation levels at the three intensities were significantly different (p
< 0.01). A significant different was also found between the rate of decrease
in total hemoglobin and myoglobin at 30% of MVC and that at 70% of MVC (p
< 0.01). Integrated electromyography was positively correlated with muscle
oxygenation level (r = -0.641, p < 0.0001). These results suggested that
muscle oxygenation level during isometric contraction reflects muscle force and
muscle activity.
