title: Knee joint function and the energy cost of level walking in soccer players.
abstract: OBJECTIVE
  To study self reported knee joint problems and the energy costs of level walking in soccer players.
  
  
  METHODS
  Seventeen soccer players and twelve control subjects between 18 and 27 years old participated in the study. A questionnaire was used to establish the amount of participation in soccer and the frequency and extent of knee injuries. The physiological cost index (PCI) was used as an index of the energy costs of level walking.
  
  
  RESULTS
  Soccer players had a significantly higher PCI than control subjects (p = 0.0001). Control subjects had a mean (SD) PCI of 0.23 (0.06) beats/m and soccer players had a mean PCI of 0.42 (0.12) beats/m. Some 82% of the soccer players experienced knee joint problems, whereas only 25% of the control group had problems.
  
  
  CONCLUSIONS
  This study shows that college soccer players have a higher rate of self reported knee problems and higher energy costs of level walking than people who do not play soccer.
authors.affiliation: Department of Physiology, Queen Mary and Westfield College, London, United Kingdom.
authors.forename: L J
authors.initials: LJ
authors.lastname: Tofts
authors.forename: C S
authors.initials: CS
authors.lastname: Stanley
authors.forename: T G
authors.initials: TG
authors.lastname: Barnett
authors.forename: J G
authors.initials: JG
authors.lastname: Logan
mesh_terms: D000293:Adolescent; D000328:Adult; D004734:Energy Metabolism / Q000502:physiology*; D006801:Humans; D015994:Incidence; D007718:Knee Injuries / Q000453:epidemiology / Q000209:etiology*; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D012016:Reference Values; D012916:Soccer / Q000502:physiology*; D016138:Walking / Q000502:physiology*