title: Effects of Off-Axis Elliptical Training on Reducing Pain and Improving Knee Function in Individuals With Patellofemoral Pain.
abstract: OBJECTIVE
  To examine whether an off-axis elliptical training program reduces pain and improves knee function in individuals with patellofemoral pain (PFP).
  
  
  METHODS
  Controlled laboratory study, pretest-posttest.
  
  
  METHODS
  University rehabilitation center.
  
  
  METHODS
  Twelve adult subjects with PFP.
  
  
  METHODS
  Subjects with PFP completed an exercise program consisting of 18 sessions of lower extremity off-axis training using a custom-made elliptical trainer that allows frontal plane sliding and transverse plane pivoting of the footplates.
  
  
  METHODS
  Changes in knee pain and function posttraining and 6 weeks after training were evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee (IKDC) scores. Lower extremity off-axis control was assessed by pivoting and sliding instability, calculated as the root mean square (RMS) of the footplate pivoting angle and sliding distance during elliptical exercise. Subjects' single-leg hop distance and proprioception in detecting lower extremity pivoting motion were also evaluated.
  
  
  RESULTS
  Subjects reported significantly greater KOOS and IKDC scores (increased by 12-18 points) and hop distance (increased by 0.2 m) after training. A significant decrease in the pivoting and sliding RMS was also observed after training. Additionally, subjects with PFP demonstrated improved pivoting proprioception when tested under a minimum weight-bearing position.
  
  
  CONCLUSIONS
  An off-axis elliptical training program was effective in enhancing lower extremity neuromuscular control on the frontal and transverse planes, reducing pain, and improving knee function in persons with PFP.
  
  
  CONCLUSIONS
  This study provides a novel intervention approach to enhance the control of the frontal and transverse plane motions of the lower extremities during functional weight-bearing activities. This novel off-axis elliptical training may be incorporated with other common treatment options currently available for PFP to augment the effects of musculoskeletal rehabilitation for the PFP population.
authors.affiliation: *Department of Physical Therapy, Georgia State University, Atlanta, Georgia; Departments of †Physical Medicine and Rehabilitation; and ‡Biomedical Engineering, Northwestern University, Chicago, Illinois; §Department of Physical Medicine and Rehabilitation, University of Colorado, Aurora, Colorado; ¶Rehabilitation Institute of Chicago, Chicago, Illinois; and ‖Department of Orthopaedic Surgery, Northwestern University, Chicago, Illinois.
authors.forename: Liang-Ching
authors.initials: LC
authors.lastname: Tsai
authors.forename: Song Joo
authors.initials: SJ
authors.lastname: Lee
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Yang
authors.forename: Yupeng
authors.initials: Y
authors.lastname: Ren
authors.forename: Joel M
authors.initials: JM
authors.lastname: Press
authors.forename: Li-Qun
authors.initials: LQ
authors.lastname: Zhang
mesh_terms: D000328:Adult; D005081:Exercise Therapy / Q000295:instrumentation* / Q000379:methods; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D046788:Patellofemoral Pain Syndrome / Q000503:physiopathology / Q000534:rehabilitation*; D020127:Recovery of Function; D055815:Young Adult