title: The effectiveness of an exercise programme on knee loading, muscle co-contraction, and pain in patients with medial knee osteoarthritis: A pilot study.
abstract: BACKGROUND
  Osteoarthritis (OA), which increases knee loading, muscle co-contraction, and pain, is a mechanical disease that requires biomechanical exploration to reduce pain in the knee. Therefore, this article aims to investigate the effectiveness of an exercise programme on the aforementioned outcomes in people with medial knee OA.
  
  
  METHODS
  Cohort pilot study design. A total of 19 patients with knee OA attended a six-week group exercise programme integrated with self-management education. The following outcomes were assessed before and after the exercise programme: external knee adduction moment (EKAM), knee adduction angular impulse (KAAI), knee antagonist muscle co-contraction, and pain subscale of the knee injury and osteoarthritis outcome score (KOOS).
  
  
  RESULTS
  Of the 19 patients, 14 completed the study. The EKAM and KAAI did not show statistical significance post-exercise intervention (p=0.21-0.7 and 0.56, respectively). Muscle co-contraction between vastus lateralis and biceps femoris muscles decreased in early-stance (64.78 (44.35) compared with 38.10 (23.10), p=0.01) and mid-stance (27.62 (32.12) compared with 14.94 (17.40), p=0.04). A corresponding significant pain reduction was observed (p=0.00) with a median (range) of 51.50 (47.00 to 62.50) at week 6 compared with 34.50 (29.25 to 41.25) at baseline.
  
  
  CONCLUSIONS
  This is the first known study to explore the effect of an exercise programme on knee loading and muscle co-contraction in patients with OA. Although the value of EKAM did not change, the findings suggest that the reduction in vastus lateralis and biceps femoris co-contraction might be the mechanism behind the reduction of pain.
authors.affiliation: School of Health Sciences, University of Salford, Salford M66PU, United Kingdom; Faculty of Rehabilitation Sciences, The University of Jordan, 11942 Amman, Jordan. Electronic address: L.Khlaifat@ju.edu.jo.
authors.forename: Lara
authors.initials: L
authors.lastname: Al-Khlaifat
authors.affiliation: School of Health Sciences, University of Salford, Salford M66PU, United Kingdom.
authors.forename: Lee C
authors.initials: LC
authors.lastname: Herrington
authors.affiliation: School of Health Sciences, University of Salford, Salford M66PU, United Kingdom.
authors.forename: Alison
authors.initials: A
authors.lastname: Hammond
authors.affiliation: School of Nursing, Midwifery and Social Work, University of Manchester, Manchester M13 9PL, United Kingdom.
authors.forename: Sarah F
authors.initials: SF
authors.lastname: Tyson
authors.affiliation: School of Health Sciences, University of Salford, Salford M66PU, United Kingdom.
authors.forename: Richard K
authors.initials: RK
authors.lastname: Jones
mesh_terms: D001696:Biomechanical Phenomena; D004576:Electromyography; D015444:Exercise / Q000502:physiology*; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D005684:Gait / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000534:rehabilitation*; D010865:Pilot Projects; D013997:Time Factors; D016896:Treatment Outcome
keywords: Co-contraction; Exercise; Loading; Osteoarthritis