title: Drop-Landing Performance and Knee-Extension Strength After Anterior Cruciate Ligament Reconstruction.
abstract: BACKGROUND
  Individuals with a history of anterior cruciate ligament reconstruction (ACLR) are at greater risk of reinjury and developing early-onset osteoarthritis due to persistent abnormal joint loading. Real-time clinical assessment tools may help identify patients experiencing abnormal movement patterns after ACLR.
  
  
  OBJECTIVE
  To compare performance on the Landing Error Scoring System (LESS) between participants with ACLR and uninjured control participants and to determine the relationship between LESS score and knee-extension strength in these participants.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  Forty-six recreationally active participants, consisting of 22 with ACLR (12 men, 10 women; age = 22.5 ± 5.0 years, height = 172.8 ± 7.2 cm, mass = 74.2 ± 15.6 kg, body mass index = 24.6 ± 4.0) and 24 healthy control participants (12 men, 12 women; age = 21.7 ± 3.6 years, height = 168.0 ± 8.8 cm, mass = 69.2 ± 13.6 kg, body mass index = 24.3 ± 3.2) were enrolled.
  
  
  METHODS
  Bilateral normalized knee-extension maximal voluntary isometric contraction (MVIC) torque (Nm/kg) and LESS scores were measured during a single testing session. We compared LESS scores between groups using a Mann-Whitney U test and the relationships between LESS scores and normalized knee-extension MVIC torque using Spearman ρ bivariate correlations.
  
  
  RESULTS
  The ACLR participants had a greater number of LESS errors (6.0 ± 3.6) than healthy control participants (2.8 ± 2.2; t44 = -3.73, P = .002). In ACLR participants, lower normalized knee-extension MVIC torque in the injured limb (ρ = -0.455, P = .03) was associated with a greater number of landing errors.
  
  
  CONCLUSIONS
  Participants with ACLR displayed more errors while landing. The occurrence of landing errors was negatively correlated with knee-extension strength, suggesting that weaker participants had more landing errors. Persistent quadriceps weakness commonly associated with ACLR may be related to a reduced quality of lower extremity movement during dynamic tasks.
authors.affiliation: Department of Kinesiology and Sport Sciences, University of Miami, FL;
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Kuenze
authors.affiliation: Department of Kinesiology, University of Virginia, Charlottesville.
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Foot
authors.affiliation: Department of Kinesiology, University of Virginia, Charlottesville.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Saliba
authors.affiliation: Department of Kinesiology, University of Virginia, Charlottesville.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Hart
mesh_terms: D016118:Anterior Cruciate Ligament / Q000502:physiology / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction; D001265:Athletic Injuries / Q000503:physiopathology; D001696:Biomechanical Phenomena / Q000502:physiology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D007718:Knee Injuries / Q000503:physiopathology; D007719:Knee Joint / Q000502:physiology* / Q000601:surgery; D008297:Male; D009068:Movement / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology; D011184:Postoperative Period; D052097:Quadriceps Muscle / Q000502:physiology; D019415:Torque; D055815:Young Adult
keywords: Landing Error Scoring System; knee-extension torque; quadriceps weakness