Okay here I found it as a short summary of the great article.
The use of near-infrared spectroscopy in
understanding skeletal muscle physiology:
BY MARCO FERRARI1,*, MAKII MUTHALIB2 AND VALENTINA QUARESIMA1
1Department of Health Sciences, University of L’Aquila, L’Aquila, Italy
2School of Human Movement Studies and Movement Neuroscience Program,
Institute of Health and Biomedical Innovation, Queensland University
of Technology, Brisbane, Queensland, Australia
This article provides a snapshot of muscle near-infrared spectroscopy (NIRS)
Table 2. Recommendations for near-infrared spectroscopy muscle studies. ATT, subcutaneous
adipose tissue thickness; CW, continuous-wave spectroscopy; EMG, electromyography; FD,
frequency-domain spectroscopy; fMRI, functional MRI; MRI, magnetic resonance imaging; NMR,
nuclear magnetic resonance spectroscopy; SRS, spatially resolved spectroscopy; PET, positron
emission tomography; TD, time-domain spectroscopy. topic current status recommendations
depth sensitivity typically approximately 1.5 cm for 3–4 cm source–detector distance. Measurements
restricted to superficial muscle(s) use TD technologies and tomographic approaches for improving depth sensitivity. In the case of multi-distance CW–NIRS, use less than 5mm and greater than 30mm for the shortest and
longest source–detector distance, respectively investigated muscle volume and measurement points
oxygenation of large muscle groups like the quadriceps is investigated by using only one or two measurement points
use multi-channel systems for investigating the spatial profile of muscle/muscle groups oxygenation
optode positioning often not accurately reported describe in detail the location,
eventually guided by ultrasound scanner
optode–skin coupling/sliding; optode sliding owing to sweat (especially in hairy skin) and/or mechanical factors
often not verified during and after the study or not mentioned
ensure an adequate stable contact between the optodes and the skin throughout the acquisition session. Minimize the sliding by bandage (avoiding venous occlusion), and use NIR transparent double-sided adhesive tape.
MOXY very early on accepted our advice in giving up on a circular system to fix MOXY on the skin. So we avoid pressure socks or garments and fix it with a tape on the tested area. In fact Roger produced a double sided option for MOXY adjustment
Monitor the pressure of the optode on the skin adipose tissue thickness often not reported measure ATT using skinfold callipers, ultrasound scanner, MRI or optical lipid signal. Eventually perform studies only on subjects with homogeneous ATT. Use algorithms for ATT correction skin blood flow changes over the exercising muscle
usually not measured measure skin blood flow (e.g. by laser Doppler) and/or skin temperature close to the optode
in prolonged exercise muscle shape changes during exercise usually not mentioned try to keep the limb movements in the same planes in order to minimize artefacts. Artefacts should be identified and corrected/eliminated in the NIRS
data analysis exercise and experimental set-up description often inaccurate describe in detail the protocol for
the reproducibility/repeatability of the measurements topic current status recommendations kinematic motor
performance motor performance not always monitored and controlled monitor motor performance by three-dimensional kinematic analysis in particular for open field exercise absolute quantification value of NIRS
measures SRS–CW-based systems provide only SmO2 (%) quantification use TD- and FD-based instrumentations for improving sensitivity and quantitation of NIRS parameters data analysis analysis of SmO2 (%) and concentration changes in O2Hb, HHb and tHb. Often only the HHb kinetics and amplitude are analysed and reported analyse and report all measurable parameters, i.e. O2Hb, HHb, tHb, SmO2 standardization no standardization is available for NIRS instrumentation/signal processing/data analysis regulatory authorities or network of research laboratories should provide ‘guidelines’ multi-modal studies very few studies integrate NIRS with MRI, fMRI, NMR, PET, EMG, microdialysis, Doppler blood flow measurements
5. Future directions
The most exciting prospect of muscle NIRS studies for the next 20 years is
the full understanding of skeletal muscle biochemistry/physiology/pathology for
improving human healthcare, athletic performance and rehabilitation monitoring.
The major challenge to achieving this understanding might be the availability
of a low-cost, easy-use optical wearable/wireless non-contact NIR imager for
obtaining four-dimensional SmO2 and haemodynamic (blood flow and tHb)
measurements of human skeletal muscle, especially during dynamic exercise.
This ideal ‘NIR imager’ should be suitable for any application (including
general health, clinical and athletic settings), and might be an addition to the
current heart rate monitoring and lactate measurements during training in the
field and health centre-like environments. This ideal ‘NIR imager’ should be
combined/integrated with other imaging and electrophysiological modalities for
enhancing the understanding of specific muscle mechanisms in pathophysiological
Considering the rapid development of related technologies, it is very difficult
to predict the potential advancements of muscle NIRS and NIR imaging. The
quantitative measurement of deep forearm oxygenation and tHb by a non-contact
oximeter prototype was proposed by Niwayama et al. .
The current typical depth sensitivity of most CW-based imagers is
approximately 1.5 cm. Therefore, a tomographic approach might provide
three-dimensional SmO2 and haemodynamic measurements. Blood flow of
Phil. Trans. R. Soc. A (2011)
12 M. Ferrari et al.
the superficial muscles might be continuously measured by diffusing-wave
spectroscopy, a new rapidly progressing technique discussed in an accompanying
symposium paper. Although three-dimensional NIR imaging of the human
forearm, based on TD techniques, was proposed by Hillman et al.  almost
10 years ago, no further progress has been made to develop the technique.
In conclusion, it is foreseeable that the availability of advanced NIR imagers
would help to refine the understanding of skeletal muscle oxygenation in different
The research is supported in part by Hamamatsu Photonics KK, Japan.
How independent should research be ?