Document Detail


Metabolic factors limiting performance in marathon runners.
MedLine Citation:
PMID:  20975938     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Each year in the past three decades has seen hundreds of thousands of runners register to run a major marathon. Of those who attempt to race over the marathon distance of 26 miles and 385 yards (42.195 kilometers), more than two-fifths experience severe and performance-limiting depletion of physiologic carbohydrate reserves (a phenomenon known as 'hitting the wall'), and thousands drop out before reaching the finish lines (approximately 1-2% of those who start). Analyses of endurance physiology have often either used coarse approximations to suggest that human glycogen reserves are insufficient to fuel a marathon (making 'hitting the wall' seem inevitable), or implied that maximal glycogen loading is required in order to complete a marathon without 'hitting the wall.' The present computational study demonstrates that the energetic constraints on endurance runners are more subtle, and depend on several physiologic variables including the muscle mass distribution, liver and muscle glycogen densities, and running speed (exercise intensity as a fraction of aerobic capacity) of individual runners, in personalized but nevertheless quantifiable and predictable ways. The analytic approach presented here is used to estimate the distance at which runners will exhaust their glycogen stores as a function of running intensity. In so doing it also provides a basis for guidelines ensuring the safety and optimizing the performance of endurance runners, both by setting personally appropriate paces and by prescribing midrace fueling requirements for avoiding 'the wall.' The present analysis also sheds physiologically principled light on important standards in marathon running that until now have remained empirically defined: The qualifying times for the Boston Marathon.
Authors:
Benjamin I Rapoport
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Publication Detail:
Type:  Journal Article     Date:  2010-10-21
Journal Detail:
Title:  PLoS computational biology     Volume:  6     ISSN:  1553-7358     ISO Abbreviation:  PLoS Comput. Biol.     Publication Date:  2010  
Date Detail:
Created Date:  2010-10-26     Completed Date:  2011-01-28     Revised Date:  2014-03-19    
Medline Journal Info:
Nlm Unique ID:  101238922     Medline TA:  PLoS Comput Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  e1000960     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Athletic Performance / physiology*
Blood Glucose / metabolism
Carbohydrate Metabolism
Computational Biology / methods*
Exercise / physiology
Fats / metabolism
Glycogen / metabolism
Humans
Metabolism
Muscle, Skeletal / metabolism*
Oxygen / metabolism
Physical Endurance / physiology*
Running / physiology*
Grant Support
ID/Acronym/Agency:
T32 GM007753/GM/NIGMS NIH HHS
Chemical
Reg. No./Substance:
0/Blood Glucose; 0/Fats; 9005-79-2/Glycogen; S88TT14065/Oxygen
Comments/Corrections

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