title: Cumulative loads increase at the knee joint with slow-speed running compared to faster running: a biomechanical study.
abstract: METHODS
  Biomechanical cross-sectional study.
  
  
  OBJECTIVE
  To investigate the hypothesis that the cumulative load at the knee during running increases as running speed decreases.
  
  
  BACKGROUND
  The knee joint load per stride decreases as running speed decreases. However, by decreasing running speed, the number of strides per given distance is increased. Running a given distance at a slower speed may increase the cumulative load at the knee joint compared with running the same distance at a higher speed, hence increasing the risk of running-related injuries in the knee.
  
  
  METHODS
  Kinematic and ground reaction force data were collected from 16 recreational runners, during steady-state running with a rearfoot strike pattern at 3 different speeds (mean ± SD): 8.02 ± 0.17 km/h, 11.79 ± 0.21 km/h, and 15.78 ± 0.22 km/h. The cumulative load (cumulative impulse) over a 1000-m distance was calculated at the knee joint on the basis of a standard 3-D inverse-dynamics approach.
  
  
  RESULTS
  Based on a 1000-m running distance, the cumulative load at the knee was significantly higher at a slow running speed than at a high running speed (relative difference, 80%). The mean load per stride at the knee increased significantly across all biomechanical parameters, except impulse, following an increase in running speed.
  
  
  CONCLUSIONS
  Slow-speed running decreases knee joint loads per stride and increases the cumulative load at the knee joint for a given running distance compared to faster running. The primary reason for the increase in cumulative load at slower speeds is an increase in number of strides needed to cover the same distance.
authors.affiliation: Section of Sport Science, Department of Public Health, Aarhus University, Aarhus, Denmark.
authors.forename: Jesper
authors.initials: J
authors.lastname: Petersen
authors.forename: Henrik
authors.initials: H
authors.lastname: Sørensen
authors.forename: Rasmus Østergaard
authors.initials: RØ
authors.lastname: Nielsen
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D012307:Risk Factors; D012420:Running / Q000293:injuries / Q000502:physiology*; D013996:Time and Motion Studies; D016474:Weight-Bearing; D055815:Young Adult
keywords: anterior knee pain; patellofemoral; run; tibiofemoral