Electrostimulation improves muscle perfusion but does not affect either muscle deoxygenation or pulmonary oxygen consumption kinetics during a heavy constant-load exercise.
Electromyostimulation (EMS) is commonly used as part of training programs. However, the exact effects at the muscle level are largely unknown and it has been recently hypothesized that the beneficial effect of EMS could be mediated by an improved muscle perfusion. In the present study, we investigated rates of changes in pulmonary oxygen consumption (VO(2p)) and muscle deoxygenation during a standardized exercise performed after an EMS warm-up session. We aimed at determining whether EMS could modify pulmonary O(2) uptake and muscle deoxygenation as a result of improved oxygen delivery. Nine subjects performed a 6-min heavy constant load cycling exercise bout preceded either by an EMS session (EMS) or under control conditions (CONT). VO(2p) and heart rate (HR) were measured while deoxy-(HHb), oxy-(HbO(2)) and total haemoglobin/myoglobin (Hb(tot)) relative contents were measured using near infrared spectroscopy. EMS significantly increased (P < 0.05) the Hb(tot) resting level illustrating a residual hyperaemia. The EMS priming exercise did not affect either the HHb time constant (17.7 +/- 14.2 s vs. 13.1 +/- 2.3 s under control conditions) or the VO(2p) kinetics (time-constant = 18.2 +/- 5.2 s vs. 15.4 +/- 4.6 s under control conditions). Likewise, the other VO(2p) parameters were unchanged. Our results further indicated that EMS warm-up improved muscle perfusion through a residual hyperaemia. However, neither VO(2p) nor [HHb] kinetics were modified accordingly. These results suggest that improved O(2) delivery by residual hyperaemia induced by EMS does not accelerate the rate of aerobic metabolism during heavy exercise at least in trained subjects.
Layec
Gwenael
G
Faculté de Médecine de Marseille, Centre de Résonance Magnétique Biologique et Médicale, UMR CNRS 6612, 27 Bd Jean Moulin, 13005, Marseille, France. gwenael.layec@medecine.univ-mrs.fr
Millet
Grégoire P
GP
Jougla
Aurélie
A
Micallef
Jean-Paul
JP
Bendahan
David
D
D000222:Adaptation, Physiological; D000328:Adult; D000332:Aerobiosis; D001642:Bicycling / Q000502:physiology; D004558:Electric Stimulation; D004734:Energy Metabolism / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006339:Heart Rate; D006454:Hemoglobins / Q000032:analysis / Q000378:metabolism; D006801:Humans; D018496:Hyperoxia / Q000097:blood / Q000378:metabolism; D007700:Kinetics; D008168:Lung / Q000098:blood supply / Q000378:metabolism; D008297:Male; D009132:Muscles / Q000098:blood supply* / Q000502:physiology*; D009211:Myoglobin / Q000032:analysis; D010100:Oxygen / Q000032:analysis / Q000378:metabolism; D010101:Oxygen Consumption; D010108:Oxyhemoglobins / Q000032:analysis / Q000378:metabolism; D010809:Physical Fitness; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012123:Pulmonary Ventilation; D019265:Spectroscopy, Near-Infrared
D006454:Hemoglobins; D009211:Myoglobin; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin; D010100:Oxygen