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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Physiol. | doi: 10.3389/fphys.2019.00506

Biomechanical adaptations and performance indicators in short trail running

  • 1Swedish Winter Sports Research Centre, Mid Sweden University, Sweden
  • 2Swedish Sports Confederation, Sweden
  • 3Royal Institute of Technology, Sweden
  • 4Swiss Federal Institute of Sport Magglingen SFISM, Switzerland
  • 5University of Salzburg, Austria

Our aims were to measure anthropometric and oxygen uptake (〖V ̇O〗_2) variables in the laboratory, to measure kinetic and stride characteristics during a trail running time trial, and then analyse the data for correlations with trail running performance. Runners (13 men, 4 women: mean age: 29±5 years; stature: 179.5±0.8 cm; body mass: 69.1±7.4 kg) performed laboratory tests to determine 〖V ̇O〗_2max, running economy, and anthropometric characteristics. On a separate day they performed an outdoor trail running time trial (two 3.5 km laps, total climb: 486 m) while we collected kinetic and time data. Comparing lap 2 with lap 1 (19:40±1:57 min vs. 21:08±2:09 min, P<0.001), runners lost most time on the uphill sections and least on technical downhills (-2.5±9.1 s). Inter-individual performance varied most for the downhills (CV>25%) and least on flat terrain (CV<10%). Overall stride cycle and ground contact time (GCT) were shorter in downhill than uphill sections (0.64±0.03 vs. 0.84±0.09 s; 0.26±0.03 vs. 0.46±0.90 s, both P<0.001). Force impulse was greatest on uphill (248±46 vs. 175±24 Ns, P<0.001) and related to GCT (r=0.904, P<0.001). Peak force was greater during downhill than during uphill running (1106±135 vs. 959±104 N, P<0.01). Performance was related to absolute and relative 〖V ̇O〗_2max (P<0.01), vertical uphill treadmill speed (P<0.001) and fat percent (P<0.01). Running uphill involved the greatest impulse per step due to longer GCT while downhill running generated the highest peak forces. 〖V ̇O〗_2max, vertical running speed and fat percent are important predictors for trail running performance. Performance between runners varied the most on downhills throughout the course, while pacing resembled a reversed J pattern. Future studies should focus on longer competition distances to verify these findings and with application of measures of 3D kinematics.

Keywords: Downhill running, Foot forces, Ground contact time, pacing, Stride frequency

Received: 01 Dec 2018; Accepted: 10 Apr 2019.

Edited by:

Francis Degache, University of Applied Sciences and Arts of Western Switzerland, Switzerland

Reviewed by:

Fabrice Vercruyssen, Université de Toulon, France
Rodger Kram, University of Colorado Boulder, United States  

Copyright: © 2019 Björklund, Swarén, Born and Stöggl. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Glenn Björklund, Swedish Winter Sports Research Centre, Mid Sweden University, Östersund, 831 25, Sweden, Glenn.Bjorklund@miun.se