title: Double-push skating versus V2 and V1 skating on uphill terrain in cross-country skiing.
abstract: OBJECTIVE
  The aims of the study were a) to compare the double-push skating technique with the V2 and the V1 skating techniques on an uphill terrain by a kinematic and kinetic analysis, b) to provide kinetic and kinematic data of the V1 technique at maximal skiing speeds, and c) to test the hypotheses that the double-push skating technique is faster compared with the V2 and the V1 skating techniques.
  
  
  METHODS
  Six elite skiers performed maximum speed sprints over a 60-m uphill section (7 degrees -10 degrees) using the double-push, the V2, and the V1 techniques. Pole and plantar forces and cycle characteristics were analyzed.
  
  
  RESULTS
  The double-push skating technique was approximately 4.3% faster (P < 0.05) compared with the V2 skating technique and equally fast compared with the V1 skating technique. The double-push and the V2 techniques demonstrated longer cycle lengths, lower cycle rates (both P < 0.05), and equal poling frequencies and pole forces compared with the V1 technique. Cycle length, peak foot force, and knee extension ranges of motion and velocities were higher in the double-push technique compared with the V2 technique (all P values <0.05). Center of pressure was located more laterally in the double-push technique compared with the other two techniques (P < 0.05). All measured skiing speeds were drastically higher compared with former studies.
  
  
  CONCLUSIONS
  The higher skiing speeds of the V1 and the double-push techniques compared with the V2 technique stress the mechanical advantage of those techniques on uphill terrain. Because of larger cycle lengths, lower cycle rate, longer recovery times, and equal poling frequency, the double-push technique might be seen as more economic on steep uphills compared with the V1 technique. From a tactical point of view compared with the V1 technique, the double-push technique needs less space due to less lateral displacement, and no technique transitions are necessary when entering and leaving an uphill section.
authors.affiliation: Department of Sport Science and Kinesiology, University of Salzburg, Salzburg, Austria. thomas.stoeggl@sbg.ac.at
authors.forename: Thomas
authors.initials: T
authors.lastname: Stöggl
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kampel
authors.forename: Erich
authors.initials: E
authors.lastname: Müller
authors.forename: Stefan
authors.initials: S
authors.lastname: Lindinger
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001317:Austria; D001696:Biomechanical Phenomena; D006801:Humans; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology; D012865:Skiing / Q000502:physiology*; D019876:Sports Equipment; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D014159:Transducers