title: RELATIONSHIP BETWEEN ISOKINETIC KNEE STRENGTH AND JUMP CHARACTERISTICS FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION.
abstract: BACKGROUND
  Clinicians are often challenged when making return-to-play decisions following anterior cruciate ligament reconstruction (ACL-R). Isokinetic strength and jump performance testing are common tools used to make this decision. Unfortunately, vertical jump performance standards have not been clearly established and many clinicians do not have access to isokinetic testing equipment.
  
  
  OBJECTIVE
  To establish normative jump and strength characteristics in ACL-R patients cleared by an orthopedic physician to return-to-play and to determine if relationships exist between knee isokinetic strength measurements and jump characteristics described using an electronic jump map system.
  
  
  METHODS
  Descriptive laboratory study.
  
  
  METHODS
  Thirty-three ACL-R patients who had been cleared to return to athletic competition participated in this study. Twenty-six of these ACL-R participants were also matched to 26 asymptomatic athletes based on sex, limb, height, and mass to determine isokinetic strength and jump characteristic differences between groups. Jump tests consisted of single leg vertical, double leg vertical, and a 4-jump single leg vertical jump assessed using an electronic jump mat system. Independent t-tests were used to determine differences between groups and multiple regression analyses were used to identify any relationships between jump performance and knee strength (p<0.05).
  
  
  RESULTS
  The ACL-R group had lower vertical jump capabilities and some bilateral knee strength deficiencies compared to the matched control group. The ACL-R group also showed several moderate-to-strong positive relationships for both knee extension and flexion strength with several jump performance characteristics, such as single and double leg vertical jump height.
  
  
  CONCLUSIONS
  The current results indicate that ACL-R patients present with several knee strength and vertical jump differences compared to a matched control group at the time of return-to-play. Also, ACL-R patient's performance on an electronic jump mat system is strongly related to isokinetic knee strength measures.
  
  
  METHODS
  2b.
authors.affiliation: Illinois State University, Normal, IL, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Laudner
authors.affiliation: Texas Metroplex Institute for Sports Medicine and Orthopedics, Arlington, TX, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Evans
authors.affiliation: Texas Metroplex Institute for Sports Medicine and Orthopedics, Arlington, TX, USA.
authors.forename: Regan
authors.initials: R
authors.lastname: Wong
authors.affiliation: Texas Metroplex Institute for Sports Medicine and Orthopedics, Arlington, TX, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Allen
authors.affiliation: Texas Metroplex Institute for Sports Medicine and Orthopedics, Arlington, TX, USA.
authors.forename: Tom
authors.initials: T
authors.lastname: Kirsch
authors.affiliation: Texas Metroplex Institute for Sports Medicine and Orthopedics, Arlington, TX, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Long
authors.affiliation: Texas Metroplex Institute for Sports Medicine and Orthopedics, Arlington, TX, USA.
authors.forename: Keith
authors.initials: K
authors.lastname: Meister
keywords: Anterior cruciate ligament; functional tests; isokinetic strength; jump mat; return‐to‐play; vertical jump