title: Lower extremity neuromuscular compensations during instrumented single leg hop testing 2-10 years following ACL reconstruction.
abstract: BACKGROUND
  This study compared lower extremity EMG activation and sagittal plane kinematics of subjects at a minimum of 2 years post-successful ACL reconstruction and rehabilitation during instrumented single leg hop testing.
  
  
  METHODS
  Comparisons were made based on subject responses to the following question, "compared to prior to your knee injury how capable are you now in performing sports activities"? Group 1=very capable, Group 2=capable, and Group 3=not capable. In addition to EMG (1000 Hz) and kinematic (60 Hz) data, subjective knee function, internal health locus of control, sports activity characteristics (intensity, frequency) pre-knee injury, and at follow-up were also compared.
  
  
  RESULTS
  Group 3 had lower perceived knee function, decreased perceived sports intensity, and more subjects with decreased sports activity intensity by two levels compared to pre-injury values. Perceived function scores, anterior laxity measurements and grades were similar between groups. During single leg hop propulsion and landing Group 1 (very capable) had greater involved lower extremity gluteus maximus and medial hamstring activation amplitudes than Group 3 (not capable). Perceived sports capability was related to better subjective knee function, and higher perceived sports activity intensity.
  
  
  CONCLUSIONS
  Neuromuscular compensations suggesting a hip bias with increased gluteus maximus and medial hamstring activation were identified at the involved lower extremity among most subjects who perceived high perceived sports capability compared to pre-injury status. These compensations may be related to a permanent neurosensory deficit, and its influence on afferent pathway changes that influence CNS sensorimotor re-organization.
authors.affiliation: Division of Sports Medicine, Department of Orthopaedic Surgery, University of Louisville, United States; Athletic Training Program, Spalding University, 901 South 4th Street, Louisville, KY 40203-2188, United States. Electronic address: jnyland@spalding.edu.
authors.forename: John
authors.initials: J
authors.lastname: Nyland
authors.affiliation: Division of Sports Medicine, Department of Orthopaedic Surgery, University of Louisville, United States; Athletic Training Program, Spalding University, 901 South 4th Street, Louisville, KY 40203-2188, United States.
authors.forename: Jeff
authors.initials: J
authors.lastname: Wera
authors.affiliation: Division of Sports Medicine, Department of Orthopaedic Surgery, University of Louisville, United States; Athletic Training Program, Spalding University, 901 South 4th Street, Louisville, KY 40203-2188, United States.
authors.forename: Scott
authors.initials: S
authors.lastname: Klein
authors.affiliation: Division of Sports Medicine, Department of Orthopaedic Surgery, University of Louisville, United States; Athletic Training Program, Spalding University, 901 South 4th Street, Louisville, KY 40203-2188, United States.
authors.forename: David N M
authors.initials: DN
authors.lastname: Caborn
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000503:physiopathology* / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction; D001696:Biomechanical Phenomena / Q000502:physiology; D004576:Electromyography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology* / Q000601:surgery; D035002:Lower Extremity / Q000503:physiopathology*; D008297:Male; D016059:Range of Motion, Articular / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology; D013177:Sports / Q000502:physiology; D013997:Time Factors; D016474:Weight-Bearing / Q000502:physiology; D055815:Young Adult
keywords: Allograft; Dynamic postural stability; Electromyography; Knee; Perceived function