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The ‘impact’ of force filtering cut-off frequency on the peak knee abduction moment during landing: artefact or ‘artifiction’?
  1. Benjamin D Roewer1,
  2. Kevin R Ford2,3,
  3. Gregory D Myer1–4,
  4. Timothy E Hewett1–4
  1. 1Sports Health and Performance Institute, The Ohio State University, Columbus, Ohio, USA
  2. 2Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
  3. 3Department of Pediatrics and Orthopaedic Surgery, College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
  4. 4Departments of Physiology and Cell Biology, Orthopaedic Surgery, Family Medicine, Biomedical Engineering and The School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, Ohio, USA
  1. Correspondence to
    Benjamin David Roewer, Sports Health and Performance Institute, The Ohio State University, 2050 Kenny Road, Suite 3100, Columbus, OH 43221, USA; Ben.Roewer{at}


Background Joint moments computed using inverse dynamic techniques are important estimators of net joint loads. Joints moments computed from marker position and ground reaction force data filtered using different cut-off frequencies may capture changes in moment magnitudes at a single joint that exceed normal physiological response. Peak external knee abduction moment (KAM) generated during landing (ie, the drop vertical jump, DVJ) predicts anterior cruciate ligament injury risk using marker and force data filtered at different cut-off frequencies. The purpose of the current investigation was to determine the effects of using the same low cut-off frequencies versus different cut-off frequencies on joint moment magnitudes to evaluate if artificial smoothing attenuates actual resultant joint loads related to injury risk.

Methods Twenty-two female, high school volleyball players performed three maximum DVJs in a laboratory setting. The average peak KAM was computed for each knee using marker and force data filtered with the same low cut-off frequencies and different cut-off frequencies.

Results Peak KAMs were significantly larger using different cut-off frequencies. The order of athletes ranked based on the magnitude of their peak KAMs did not significantly change across all filtering cut-off frequencies.

Conclusions The magnitude of peak KAM may differ when the same low or different higher cut-off frequencies are used to filter marker and ground reaction forces (GRF) data collected using standard motion capture equipment. It is not clear to what extent the decrease in peak KAM reported when the same low cut-off frequencies were used was solely due to attenuation of the GRF signal.

  • ACL
  • Injury Prevention
  • Knee
  • Knee ACL
  • Landing impact

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