Physiological, biochemical, anthropometric, and biomechanical influences on exercise economy in humans.
Interindividual variation in running and cycling exercise economy (EE) remains unexplained although studied for more than a century. This study is the first to comprehensively evaluate the importance of biochemical, structural, physiological, anthropometric, and biomechanical influences on running and cycling EE within a single study. In 22 healthy males (VO2max range 45.5-72.1 mL·min-1·kg-1), no factor related to skeletal muscle structure (% slow-twitch fiber content, number of capillaries per fiber), mitochondrial properties (volume density, oxidative capacity, or mitochondrial efficiency), or protein content (UCP3 and MFN2 expression) explained variation in cycling and running EE among subjects. In contrast, biomechanical variables related to vertical displacement correlated well with running EE, but were not significant when taking body weight into account. Thus, running EE and body weight were correlated (R2=.94; P<.001), but was lower for cycling EE (R2=.23; P<.023). To separate biomechanical determinants of running EE, we contrasted individual running and cycling EE considering that during cycle ergometer exercise, the biomechanical influence on EE would be small because of the fixed movement pattern. Differences in cycling and running exercise protocols, for example, related to biomechanics, play however only a secondary role in determining EE. There was no evidence for an impact of structural or functional skeletal muscle variables on EE. Body weight was the main determinant of EE explaining 94% of variance in running EE, although more than 50% of the variability of cycling EE remains unexplained.
Department of Food & Nutrition & Sport Science, Gothenburg University, Gothenburg, Sweden.|Zürich Center for Integrative Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland.
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http://orcid.org/0000-0002-1684-0026
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Lundby
Zürich Center for Integrative Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland.
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Montero
Zürich Center for Integrative Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland.
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Gehrig
Department of Food & Nutrition & Sport Science, Gothenburg University, Gothenburg, Sweden.
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Andersson Hall
Zürich Center for Integrative Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland.
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Kaiser
School of Kinesiology, University of British Columbia, Vancouver, Canada.
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Boushel
Zürich Center for Integrative Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland.
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Meinild Lundby
Zürich Center for Integrative Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland.
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Kirk
Universitätsklinik Balgrist, Zürich, Switzerland.
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Valdivieso
Universitätsklinik Balgrist, Zürich, Switzerland.
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Flück
Department of Anesthesia, The Copenhagen Muscle Research Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
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Secher
Department of Food & Nutrition & Sport Science, Gothenburg University, Gothenburg, Sweden.
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Edin
Department of Food & Nutrition & Sport Science, Gothenburg University, Gothenburg, Sweden.
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Hein
Department of Food & Nutrition & Sport Science, Gothenburg University, Gothenburg, Sweden.
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Madsen
D000328:Adult; D000886:Anthropometry; D001642:Bicycling / Q000502:physiology*; D001696:Biomechanical Phenomena; D001823:Body Composition; D001835:Body Weight; D003430:Cross-Sectional Studies; D004734:Energy Metabolism; D005080:Exercise Test; D006801:Humans; D008297:Male; D008931:Mitochondria, Muscle / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D010101:Oxygen Consumption; D012420:Running / Q000502:physiology*; D055815:Young Adult
biomechanic; locomotion; mitochondria; skeletal muscle