Muscle oxygenation dynamics in response to electrical stimulation as measured with near-infrared spectroscopy: A pilot study.Neuromuscular electrical stimulation (NMES) is used for preventing muscle atrophy and improving muscle strength in patients and healthy people.  We applied near-infrared spectroscopy (NIRS) to measure instantaneous tissue oxygenation and deoxygenation changes in 43 healthy young adults during NMES at 10, 15, 20, 25, 30, and 35 mA. 
near-infrared spectroscopy
We applied near-infrared spectroscopy (NIRS) to measure instantaneous tissue oxygenation and deoxygenation changes in 43 healthy young adults during NMES at 10, 15, 20, 25, 30, and 35 mA.  Having been stabilized at the NIRS signal baseline, the tissue oxygenation and total hemoglobin concentration increased immediately after stimulation in a dose-dependent manner (P < 0.05) until stimulation was stopped at the level causing muscle contraction without pain.  We conclude that NIRS can be used to determine the optimal NMES current intensity by monitoring oxygenation changes.
NIRS