Document Detail


Biomechanically influenced differences in O2 extraction in diagonal skiing: arm versus leg.
MedLine Citation:
PMID:  20216469     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: This study aimed to determine whether the differences in oxygen extraction and lactate concentration in arms and legs during cross-country skiing are related to muscle activation or force production and how these differences are influenced by a reduction in exercise intensity.
METHODS: Nine well-trained male cross-country skiers (age = 22 +/- 3 yr, V˙O2max = 5.3 +/- 0.3 L min(-1) and 69 +/- 3 mL kg(-1) min(-1)) performed diagonal skiing on a treadmill for 3 min at 90% followed by 6 min at 70% of V˙O2max. During the final minute of each workload, arterial, femoral, and subclavian venous blood was collected for determination of blood gases, pH, and lactate. EMG was recorded from six upper- and lower-body muscles, and leg and pole forces were measured. Cardiorespiratory variables were monitored continuously.
RESULTS: Oxygen extraction in the legs was higher than that in the arms at both 90% and 70% of V˙O2max (92% +/- 3% vs 85% +/- 6%, P < 0.05 and 90% +/- 3% vs 78% +/- 8%, P < 0.001). This reduction with decreased workload was more pronounced in the arms (-9.8% +/- 7.7% vs -3.2% +/- 3.2%, P < 0.01). EMG(RMS) for the arms was higher, and pole ground contact time was greater than the corresponding values for the legs (both P < 0.01). At both intensities, the blood lactate concentration was higher in the subclavian than that in the femoral vein but was lowered more in the subclavian vein when intensity was reduced (all P < 0.001).
CONCLUSIONS: The higher muscle activation (percentage of maximal voluntary isometric contraction) in the arms and the longer ground contact time of the poles than the legs contribute to the lower oxygen extraction and elevated blood lactate concentration in the arms in diagonal skiing. The better lactate recovery in the arms than that in the legs is aided by greater reductions in muscle activation and pole force when exercise intensity is reduced.
Authors:
Glen Björklund; Thomas Stöggl; Hans-Christer Holmberg
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  42     ISSN:  1530-0315     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  2010 Oct 
Date Detail:
Created Date:  2010-09-27     Completed Date:  2011-01-13     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1899-908     Citation Subset:  IM; S    
Affiliation:
Department of Health Sciences, Swedish Winter Sports Research Centre, Mid-Sweden University, Ostersund, Sweden. glenn.bjorklund@miun.se
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MeSH Terms
Descriptor/Qualifier:
Adult
Arm / blood supply,  physiology*
Athletes
Biomechanics / physiology
Blood Gas Analysis
Exercise / physiology
Humans
Hydrogen-Ion Concentration
Isometric Contraction / physiology
Lactic Acid / blood
Leg / blood supply,  physiology*
Male
Muscle Strength / physiology
Muscle, Skeletal / blood supply,  physiology
Oxygen Consumption / physiology*
Skiing / physiology*
Young Adult
Chemical
Reg. No./Substance:
50-21-5/Lactic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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