title: Association of the Single-Limb Hop Test With Isokinetic, Kinematic, and Kinetic Asymmetries in Patients After Anterior Cruciate Ligament Reconstruction.
abstract: BACKGROUND
  Asymmetries persist after anterior cruciate ligament reconstruction (ACLR). Physical performance tests such as the single-limb hop test have been used extensively to assess return-to-sport criteria, as they reproduce dynamic athletic maneuvers.
  
  
  OBJECTIVE
  The single-limb hop is associated with muscle strength and kinematic and kinetic asymmetries in ACLR patients 6 to 9 months after surgery.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Twenty-two men with ACLR (mean age, 28.8 ± 11.2 years) at 6 to 9 months (mean, 7.01 ± 0.93 months) after surgery completed isokinetic testing in 3 velocities (120, 180, and 300 deg/s) and a kinetic, kinematic, and functional evaluation of the single-limb hop test. Pearson correlation coefficients were used to assess the relationship between the Limb Symmetry Index (LSI) of the single-limb hop distance and each of the outcome variables.
  
  
  RESULTS
  There were significant positive correlations between the LSI of the single-limb hop distance and the LSI of the peak extension torque at 120 deg/s (P = 0.044, r = 0.37) and the peak extension torque at 180 deg/s (P = 0.042, r = 0.38) as well as a negative correlation with the peak flexion torque at 180 deg/s (P = 0.043, r = -0.38). The LSI of the single-limb hop test was not correlated with any kinetic or kinematic variable (P > 0.05).
  
  
  CONCLUSIONS
  The findings of the present study demonstrate that distance LSI of the single-limb hop test correlates with isokinetic extension peak torque LSI but not kinetic and kinematic asymmetry.
  
  
  CONCLUSIONS
  The single-limb hop test can be used as an additional tool for the recognition of muscle strength asymmetries but not for kinetic or kinematic asymmetries 6 to 9 months after ACLR.
authors.affiliation: Orthopaedic Sports Medicine Center, Department of Orthopaedic Surgery, University of Ioannina, Ioannina, Greece.
authors.forename: Sofia A
authors.initials: SA
authors.lastname: Xergia
authors.affiliation: Discipline of Physiotherapy, Faculty of Health Sciences, University of Sydney, Sydney, New South Wales, Australia ; Department of Physical Therapy, Long Island University-Brooklyn Campus, Brooklyn, New York.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Pappas
authors.affiliation: Orthopaedic Sports Medicine Center, Department of Orthopaedic Surgery, University of Ioannina, Ioannina, Greece.
authors.forename: Anastasios D
authors.initials: AD
authors.lastname: Georgoulis
keywords: anterior cruciate ligament reconstruction; hop tests; isokinetics; kinematics; kinetics