Measurement of Low Back Muscle Fatigue and Recovery Time During and After Isometric Endurance Test

摘要

The aim of this study was to examine the relationship between myo-electrical manifestation and muscle oxygenation level by surface electromyography (EMG) and Near-infrared spectroscopy (NIRS), respectively. As well as the recovery time based on tissue oxygenation index (TOI) after isometric exercise on erector spinae muscle (ESM). Eleven healthy females (age= 18.8 ± 0.7 years, height= 1.59 ± 0.0 m, BMI= 20.1 ± 1.8; mean ± SD) performed an isometric back trunk extension (Biering-S?rensen Muscle Endurance test-BSME) of their 40 % of their mean maximal voluntary contraction (MVC) until exhaustion. Muscle oxygenation decreased immediately at the beginning of exercise. Maximal deoxy-genation occurred at 100 % BSME time, and decreased about 15 % from the resting value. A strong correlation between frequency content of the EMG signal and TOI was established, r= 0.78 (right) and r= 0.90 (left). These findings suggest that the fatigue resulting from sustained isometric exercise are related to a decrease in oxygenation level following by the increasing time of contraction of the ESM.