Affiliations: [a] Department of Sports Medicine, LKH Innsbruck,
Innsbruck, Austria | [b] Department of Anesthesiology and Critical Care
Medicine, LKH Voecklabruck, Voecklabruck, Austria | [c] University Department of Anesthesiology and Critical
Care Medicine, Medical University of Innsbruck, Innsbruck, Austria | [d] Institute for Leisure, Travel and Alpine Medicine,
University for Health Sciences, Medical Informatics and Technology, Hall,
Austria
Note: [] Address for correspondence: Dr. Arnold Koller, LKH Innsbruck,
Anichstrasse 35, A-6020 Innsbruck, Austria. Tel.: +43 512 504 23477; Fax: +43
512 504 23469; E-mail: arnold.koller@uklibk.ac.at
Abstract: Background: A shift in the angle of peak torque (APT) during maximal
voluntary isokinetic concentric knee flexions and extensions has been
demonstrated following eccentric and stepping exercise. Objective: To test the hypothesis that downhill marathon
running is associated with a shift in the APT towards longer muscle length.
Methods: Twelve male runners performed an isokinetic muscle
test three to four days before and 18 hours after a downhill marathon. Both
legs were tested and the testing protocol consisted of concentric and eccentric
quadriceps and hamstring contractions at 60°/s. Results: There were no significant differences between
quadriceps peak torque (PT) before and after the race. There was a bilateral
shift in the APT of the quadriceps to a more extended position in the
concentric but not in the eccentric testing mode. Conclusion: Running a downhill marathon is not associated with
concentric and eccentric quadriceps fatigue. Prolonged downhill running could
result in changes in muscle properties expressed in a shift in the APT towards
shorter muscle lengths without significant force deficits in the concentric
testing mode. By contrast, there was no shift in the APT in the eccentric
testing mode challenging the functional significance of moving the angle of
peak maximal voluntary concentric torque of the quadriceps muscles in
connection with a downhill marathon.
