title: Intrasession and Intersession Reliability of Running Mechanics During Treadmill Sprints.
abstract: OBJECTIVE
  To determine the intrasession and intersession (ie, within- and between-days) reliability in treadmill sprinting-performance outcomes and associated running mechanics.
  
  
  METHODS
  After familiarization, 13 male recreational sportsmen (team- and racket-sport background) performed three 5-s sprints on an instrumented treadmill with 2 min recovery on 3 different days, 5-7 d apart. Intrasession (comparison of the 3 sprints of the first session) and intersession (comparison of the average of the 3 sprints across days) reliability of performance, kinetics, kinematics, and spring-mass variables were assessed by intraclass correlation coefficient (ICC) and coefficients of variation (CV%).
  
  
  RESULTS
  Intrasession reliability was high (ICC > .94 and CV < 8%). Intersession reliability was good for performance indices (.83 < ICC < .89 and CV < 10%, yet with larger variability for mean velocity than for distance covered or propulsive power) and kinetic parameters (ICC > .94 and CV < 5%, yet with larger variability for mean horizontal forces than for mean vertical forces) and ranged from good to high for all kinematic (.88 < ICC < .95 and CV ≤ 3.5%) and spring-mass variables (.86 < ICC < .99 and CV ≤ 6.5%). Compared with intrasession, minimal detectable differences were on average twice larger for intersession designs, except for sprint kinetics.
  
  
  CONCLUSIONS
  Instrumented treadmill sprint offers a reliable method of assessing running mechanics during single sprints either within the same session or between days.
authors.affiliation: Inst of Sport Sciences, University of Lausanne, Switzerland.
authors.forename: Olivier
authors.initials: O
authors.lastname: Girard
authors.forename: Franck
authors.initials: F
authors.lastname: Brocherie
authors.forename: Jean-Benoit
authors.initials: JB
authors.lastname: Morin
authors.forename: Grégoire P
authors.initials: GP
authors.lastname: Millet
mesh_terms: D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D001696:Biomechanical Phenomena; D005080:Exercise Test; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D012420:Running / Q000502:physiology*