Intérêt de la spectroscopie dans le proche infrarouge de l'hémoglobine pour l'étude de l'oxygénation musculaire du vastus lateralis lors d'une épreuve d'effort

Abstract

Aims We study the muscle oxygenation of the vastus lateralis muscle (VL) during an incremental exercise and the local changes of muscle oxygenation with fatigue. Methods Seven well-trained triathletes and runners (age: 26.4 ± 1.3 years) performed an incremental exercise on a treadmill (beginning: 12 km.h −1; added 1 km.h −1 every 2 min up to exhaustion). O 2 uptake ( V . O 2 ), heart rate (HR) and ventilatory components were recorded with a Cosmed K4 at rest, during exercise and 6 min recuperation (3 min walking, 3 min standing). Determination of the aerobic threshold (AT) and of the respiratory compensation point (RCP) was realised by the V- slope method. The near infrared spectroscopy of haemoglobin allowed the measurement of the concentration of the vastus lateralis muscle (VL) oxygenation. The probe was fixed on the left VL at 15 cm of the knee joint, along the vertical axis of the thigh. Results Our results showed that AT and RCP corresponded to 70 ± 2.8% and 88 ± 2.8% of the V . O 2 max. During exercise, [HbO 2]/[Hbtot] signal showed two breaking point (D1, D2) corresponding to 70.6 ± 0.6% and 89.1 ± 1.1% of the V . O 2 max. D2 correlated with RCP (R = 0.558, p < 0.05), but D1 and AT had only a similar evolution. HR correlated with [HbO 2]/[Hbtot], (R = 0.986, p < 0.001). Conclusion Using the near infrared spectroscopy of haemoglobin method during incremental exercise allowed the detection of the aerobic–anaerobic threshold of the exercising muscle.