A waterproof spectrometer capable of measuring muscle oxygenation underwater has been developed by scientists in the UK. The device, which has been described in the Journal of Biomedical Optics (JBO), would be beneficial for swimmers monitoring their performance, or for patients looking to heal injured muscles through water-based therapies.
The team of researchers from the University of Essex in the UK and Dutch company Artinis Medical Systems developed the near-infrared device to a provide swimmers with valuable feedback, ensuring that working muscles have enough oxygen to sustain long, high-performance workouts.
At present, there is a limited choice of monitoring equipment for swimmers on the market, compared to the broad range of wearable devices available for use in field-based sports, driven by advances in sensor technology. ‘There are limited methods available for real-time measurements of human performance underwater. This is especially true during dynamic exercise as occurs in sport,’ said JBO associate editor Marco Ferrari, a professor at the University of L'Aquila in Italy.
Near-infrared spectroscopy uses light waves from the near-infrared region of the electromagnetic spectrum, and is widely used in sensors for food and chemical quality control, in medical diagnostics such as for detecting bone diseases early, or in monitoring brain or nerve functions.
However, the available portable devices are not waterproof, and the aquatic environment provides an exercise medium within which any physiological measurement is difficult to make.
To make the device waterproof, the researchers carried out an analysis of the effect of water immersion and temperature upon device function, as described in the paper published in JBO. Firstly, the light sources were covered with standard waterproof materials, however, it was found that this affected the NIR light intensities considerably. The team then modified a commercially available silicone coating by adding polyvinyl chloride, which is impermeable to NIR radiation, to overcome this problem.
‘This paper is the first demonstration of the use of near-infrared spectroscopy to measure muscle oxygenation in athletes during swimming,' added Cooper. 'It has implications not only as a new way to monitor sports performance, but also as a way of tracking and optimising rehabilitation using water-based therapies such as cold-water immersion therapy.
‘The development of a waterproof near-infrared device will facilitate measurement of muscle oxygenation and blood flow in a previously inaccessible exercise setting,' he concluded.