Endurance training reduces end-exercise VO2 and muscle use during submaximal cycling

• Published in: Medicine and science in sports and exercise 2003-02, Vol.35 (2), p.257-262
• Main Authors: SAUNDERS, Michael J, EVANS, Ellen M, ARNGRIMSSON, Sigurbjorn A, ALLISON, Jerry D, CURETON, Kirk J
• Format: Article
• Language: English
• Subjects: Adult; Bicycling - physiology; Biological and medical sciences; Female; Fundamental and applied biological sciences. Psychology; Humans; Kinetics; Magnetic Resonance Imaging; Male; Muscle, Skeletal - physiology; Oxygen Consumption; Physical Endurance - physiology; Space life sciences; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports
• ISSN: 0195-9131; 1530-0315
• DOI: 10.1249/01.MSS.0000048726.30184.90

End-exercise VO2 during heavy, constant-load exercise is reduced after endurance training, due to an attenuated VO2 slow component. To determine whether the training-induced reduction in end-exercise VO2 was associated with reduced muscle use, we measured VO2 and T2 changes in magnetic resonance images in the final minute of two 15-min constant-load cycle rides, one above lactate threshold and the other below lactate threshold. These measures were repeated after a 4-wk period in eight subjects who trained on a cycle ergometer and seven controls. There were no changes in end-exercise VO2 or active muscle after training in either group during low-intensity cycling, in which no VO2 slow component was present. During high-intensity cycling, in which there was a slow component before training, the training group experienced a significant reduction (P < 0.05) in end-exercise VO2 (2625 +/- 673; 2567 +/- 605 mL.min (-1) and the T2 of the vastus lateralis (35.6 +/- 1.4; 34.5 +/- 0.9 ms). These results support the hypothesis that reduction in end-exercise VO2 (and the VO2 slow component) after training is due to reduced muscle use during heavy, constant load cycling.