Mapping of calf muscle oxygenation and haemoglobin content during dynamic plantar flexion exercise by multi-channel time-resolved near-infrared spectroscopy

Phys Med Biol. 2004 Mar 7;49(5):685-99. doi: 10.1088/0031-9155/49/5/003.


A compact and fast multi-channel time-resolved near-infrared spectroscopy system for tissue oximetry was developed. It employs semiconductor laser and fibre optics for delivery of optical signals. Photons are collected by eight 1 mm fibres and detected by a multianode photomultiplier. A time-correlated single photon counting board is used for the parallel acquisition of time-resolved reflectance curves. Estimate of the reduced scattering coefficient is achieved by fitting with a standard model of diffusion theory, while the modified Lambert-Beer law is used to assess the absorption coefficient. In vivo measurements were performed on five healthy volunteers to monitor spatial changes in calf muscle (medial and lateral gastrocnemius; MG, LG) oxygen saturation (SmO2) and total haemoglobin concentration (tHb) during dynamic plantar flexion exercise performed at 50% of the maximal voluntary contraction. At rest SmO2 was 73.0 +/- 0.9 and 70.5 +/- 1.7% in MG and LG, respectively (P = 0.045). At the end of the exercise, SmO2 decreased (69.1 +/- 1.8 and 63.8 +/- 2.1% in MG and LG, respectively; P < 0.01). The LG desaturation was greater than the MG desaturation (P < 0.02). These results strengthen the role of time-resolved near-infrared spectroscopy as a powerful tool for investigating the spatial and temporal features of muscle SmO2 and tHb.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue
  • Adult
  • Exercise*
  • Hemoglobins / metabolism*
  • Humans
  • Kinetics
  • Male
  • Middle Aged
  • Muscle Contraction
  • Muscle, Skeletal / metabolism
  • Muscle, Skeletal / pathology*
  • Oximetry / methods*
  • Oxygen / metabolism*
  • Phantoms, Imaging
  • Photons
  • Spectrophotometry
  • Spectroscopy, Near-Infrared / methods*
  • Time Factors


  • Hemoglobins
  • Oxygen