Effects of arterial oxygen content on peripheral locomotor muscle fatigue

Effects of arterial oxygen content on peripheral locomotor muscle fatigue

John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin Medical School, Madison, Wisconsin Submitted 20 December 2005 ; accepted in final form 15 February 2006 The effect of arterial O 2 content (Ca O 2 ) on quadriceps fatigue was assessed in healthy, trained male athletes. On separate...

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Bibliographic Details
Published in:Journal of applied physiology (1985) Vol. 101; no. 1; pp. 119 - 127
Main Authors: Amann, Markus, Romer, Lee M, Pegelow, David F, Jacques, Anthony J, Hess, C. Joel, Dempsey, Jerome A
Format: Journal Article
Language:English
Published: Bethesda, MD Am Physiological Soc 01-07-2006
American Physiological Society
Subjects:
Adult
Athletes
Biological and medical sciences
Blood
Electromyography
Exercise - physiology
Exercise Test
Fatigue
Fundamental and applied biological sciences. Psychology
Humans
Hypoxia
Male
Motor Activity - physiology
Motor Neurons - physiology
Muscle Contraction - physiology
Muscle Fatigue - physiology
Muscular system
Oxygen - blood
Oxygen - physiology
Oxygen Consumption - physiology
Quadriceps Muscle - innervation
Quadriceps Muscle - physiology
Studies
Oxygen
Saturation
Fatigue
Striated muscle
Oxygen content
magnetic femoral nerve stimulation
Vertebrata
Mammalia
hemoglobin saturation
Hyperoxia
Magnetic stimulus
Hemoglobin
Hypoxia
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Summary:John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin Medical School, Madison, Wisconsin Submitted 20 December 2005 ; accepted in final form 15 February 2006 The effect of arterial O 2 content (Ca O 2 ) on quadriceps fatigue was assessed in healthy, trained male athletes. On separate days, eight participants completed three constant-workload trials on a bicycle ergometer at fixed workloads (314 ± 13 W). The first trial was performed while the subjects breathed a hypoxic gas mixture [inspired O 2 fraction (F I O 2 ) = 0.15, Hb saturation = 81.6%, Ca O 2 = 18.2 ml O 2 /dl blood; Hypo] until exhaustion (4.5 ± 0.4 min). The remaining two trials were randomized and time matched with Hypo. The second and third trials were performed while the subjects breathed a normoxic (F I O 2 = 0.21, Hb saturation = 95.0%, Ca O 2 = 21.3 ml O 2 /dl blood; Norm) and a hyperoxic (F I O 2 = 1.0, Hb saturation = 100%, Ca O 2 = 23.8 ml O 2 /dl blood; Hyper) gas mixture, respectively. Quadriceps muscle fatigue was assessed via magnetic femoral nerve stimulation (1–100 Hz) before and 2.5 min after exercise. Myoelectrical activity of the vastus lateralis was obtained from surface electrodes throughout exercise. Immediately after exercise, the mean force response across 1–100 Hz decreased from preexercise values ( P < 0.01) by –26 ± 2, –17 ± 2, and –13 ± 2% for Hypo, Norm, and Hyper, respectively; each of the decrements differed significantly ( P < 0.05). Integrated electromyogram increased significantly throughout exercise ( P < 0.01) by 23 ± 3, 10 ± 1, and 6 ± 1% for Hypo, Norm, and Hyper, respectively; each of the increments differed significantly ( P < 0.05). Mean power frequency fell more ( P < 0.05) during Hypo (–15 ± 2%); the difference between Norm (–7 ± 1%) and Hyper (–6 ± 1%) was not significant ( P = 0.32). We conclude that Ca O 2 during strenuous systemic exercise at equal workloads and durations affects the rate of locomotor muscle fatigue development. hypoxia; hyperoxia; hemoglobin saturation; magnetic femoral nerve stimulation Address for reprint requests and other correspondence: M. Amann, John Rankin Laboratory of Pulmonary Medicine, 4245 Medical Science Center, 1300 Univ. Ave., Madison, WI 53706 (e-mail: amann{at}wisc.edu )
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ISSN:8750-7587
1522-1601
DOI:10.1152/japplphysiol.01596.2005