title: A novel clinical approach for assessing hop landing strategies: a 2D telescopic inverted pendulum (TIP) model.
abstract: OBJECTIVE
  Single leg hop for distance is used to inform rehabilitation and return to sport following anterior cruciate ligament reconstruction. However, impairment of landing mechanics may persist after the recommended performance parameter (hop distance) has been met; therefore, alternative methods are required. This study follows the COSMIN guideline to investigate the measurement properties of data from a new instrument (2D TIP). This is a simple motion analysis instrument to assess landing strategy based on more complex biomechanical modelling.
  
  
  METHODS
  Data collected in the clinical setting from 30 subjects with chronic ACL deficiency (mean 15.5, SD 4.3 months following injury) before and 6 months after ACL reconstruction and a healthy control group were analysed. Reliability and measurement error were calculated using two repeated measures from three independent raters. Construct validity was assessed by hypothesis testing, and known groups validity and responsiveness were defined by differences between groups.
  
  
  RESULTS
  The data demonstrate excellent inter-rater (ICC = 0.81-1.00) and intra-rater (ICC = 0.85-1.00) reliability with low measurement error. Of the eight construct validity hypothesis, six were fully and two partially supported. Between-group differences were significant (P < 0.05) supporting the validity and responsiveness hypothesis.
  
  
  CONCLUSIONS
  2D TIP is a simple and inexpensive instrument for assessing landing strategy that has demonstrated appropriate reliability, validity and responsiveness in the ACL-injured population. The instrument will now be used to identify altered movement strategies and develop novel rehabilitation interventions that target strategy and performance.
  
  
  METHODS
  Prospective diagnostic study, Level II.
authors.affiliation: School of Healthcare Sciences, Cardiff University, Second Floor, Cardigan House, Heath Park Campus, Cardiff, CF14 4XN, UK. letchfordrh@cf.ac.uk.|Aneurin Bevan Health Board, Physiotherapy Department, Royal Gwent Hospital, Cardiff Road, Newport, Gwent, NP20 2UB, UK. letchfordrh@cf.ac.uk.
authors.forename: Robert
authors.initials: R
authors.lastname: Letchford
authors.affiliation: School of Healthcare Sciences, Cardiff University, Second Floor, Cardigan House, Heath Park Campus, Cardiff, CF14 4XN, UK.|Arthritis Research UK Biomechanics and Bioengineering Centre, Cardiff University, Cardiff, UK.|Cardiff and Vale University Health Board, Physiotherapy Department, University Hospital of Wales, Heath Park, Cardiff, CF14 4XN, UK.
authors.forename: Kate
authors.initials: K
authors.lastname: Button
authors.affiliation: School of Healthcare Sciences, Cardiff University, Second Floor, Cardigan House, Heath Park Campus, Cardiff, CF14 4XN, UK.|Arthritis Research UK Biomechanics and Bioengineering Centre, Cardiff University, Cardiff, UK.|Cardiff and Vale University Health Board, Physiotherapy Department, University Hospital of Wales, Heath Park, Cardiff, CF14 4XN, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Adamson
authors.affiliation: School of Healthcare Sciences, Cardiff University, Second Floor, Cardigan House, Heath Park Campus, Cardiff, CF14 4XN, UK.|Arthritis Research UK Biomechanics and Bioengineering Centre, Cardiff University, Cardiff, UK.
authors.forename: Paulien E
authors.initials: PE
authors.lastname: Roos
authors.affiliation: School of Healthcare Sciences, Cardiff University, Second Floor, Cardigan House, Heath Park Campus, Cardiff, CF14 4XN, UK.|Arthritis Research UK Biomechanics and Bioengineering Centre, Cardiff University, Cardiff, UK.
authors.forename: Valerie
authors.initials: V
authors.lastname: Sparkes
authors.affiliation: School of Healthcare Sciences, Cardiff University, Second Floor, Cardigan House, Heath Park Campus, Cardiff, CF14 4XN, UK.|Arthritis Research UK Biomechanics and Bioengineering Centre, Cardiff University, Cardiff, UK.
authors.forename: Robert W M
authors.initials: RW
authors.lastname: van Deursen
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000534:rehabilitation*; D002908:Chronic Disease; D003949:Diagnostic Techniques, Surgical; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis* / Q000601:surgery; D008297:Male; D008954:Models, Biological; D011446:Prospective Studies; D015203:Reproducibility of Results; D000068958:Return to Sport; D013708:Tendon Injuries / Q000175:diagnosis* / Q000601:surgery
keywords: ACL; Clinical biomechanics; Knee; Movement analysis; Physiotherapy; Rehabilitation