The Influence of Muscle Length on Muscle Oxygen Saturation

Abstract

Previous studies have suggested that chronic stretch might be able to produce skeletal muscle hypertrophy. However, stretching might also result in restricted blood flow which might influence any stretch-training program. PURPOSE: This study evaluated the influence of muscle position (shortened, neutral, and stretched) on muscle oxygen saturation using near infrared spectroscopy (NIRS). METHODS: An 8 channel NIRS probe was placed on the gastrocnemius muscles of 5 healthy adults. Measurements were made over 30 minutes in the three positions with the subjects performing 5 second maximal contractions once every minute. Oxygen saturation values were normalized with ischemia and reperfusion. RESULTS: Oxygen saturation before (rest) and during the different conditions are shown in the table below (means + SD). The stretched position significantly lowered oxygen saturation relative to the other conditions. CONCLUSION: Stretching either passively or with contractions decreased oxygen saturation, such that stretch training may also have a significant hypoxic component.Table