Hemoglobin near-infrared spectroscopy and surface EMG study in muscle ischaemia and fatiguing isometric contraction

• Published in: Journal of sports medicine and physical fitness Vol. 39; no. 2; pp. 83 - 92
• Main Authors: ALFONSI, E, PAVESI, R, MERLO, I. M, GELMETTI, A, ZAMBARBIERI, D, LAGO, P, ARRIGO, A, REGGIANI, C, MOGLIA, A
• Format: Journal Article
• Language: English
• Published: Torino Minerva medica 01.06.1999; Edizioni Minerva Medica
• Subjects: Adult; Algorithms; Biological and medical sciences; Electromyography; Fundamental and applied biological sciences. Psychology; Hemoglobins - analysis; Humans; Ischemia - physiopathology; Isometric Contraction - physiology; Light; Male; Muscle Fatigue - physiology; Muscle, Skeletal - blood supply; Muscle, Skeletal - physiopathology; Oxygen Consumption - physiology; Space life sciences; Spectroscopy; Spectroscopy, Near-Infrared; Striated muscle. Tendons; Vertebrates: osteoarticular system, musculoskeletal system; Human; Near infrared spectrometry; Ischemia; Electrophysiology; Hemoglobin; Isometric muscular contraction; Fatigue; Electromyography; Striated muscle
• ISSN: 0022-4707; 1827-1928

To assess how muscle ischaemia and isometric fatiguing contraction influence oxygen content in striated muscle. We simultaneously measured changes in hemoglobin near-infrared (NIR) spectroscopy and in surface EMG before, during, and after muscle ischaemia and ischaemia plus muscle isometric fatiguing contraction. Seventeen healthy male subjects (age range: 19-40 yrs) were examined in our Clinical Neurophysiology Unit. Test I (9 subjects): hemoglobin NIR spectroscopy and stimulated surface EMG were measured for 2 minutes at rest, for 4 minutes during complete ischaemia of tibialis anterior muscle, and for twelve minutes during recovery. Test II (all subjects): hemoglobin NIR spectroscopy and surface EMG were measured for 2 minutes with the subjects performing brief non-fatiguing contractions, for 4 minutes with the subject performing maximal isometric contraction in complete ischaemia, and for twelve minutes during recovery. EMG parameters measured: median density frequency (MDF); muscle fiber conduction velocity (MFCV). NIR spectroscopy parameters measured: percentage of amplitude decrement (% AD) and nadir time (NT) during ischaemia and ischaemic effort; half-recovery time (1/2 RT) from ischaemia effort. At EMG, we observed a significant shift towards lower values of both MFCV and MDF during fatiguing isometric contraction. MDF recovery was faster then MFCV recovery. At NIR spectroscopy, the 1/2 RT slowed a fast pattern in twelve subjects and a slow pattern in five. A significant relationship was found between AD% and 1/2 RT values of test I and AD% and 1/2 values of test II. We found a positive relationship between NT and 1/2 RT in test II. Surface EMG and hemoglobin NIR spectroscopy can be applied simultaneously to evaluate both fatigue intensity and blood flow changes in striated muscle.