title: The effects of high-intensity versus low-intensity resistance training on leg extensor power and recovery of knee function after ACL-reconstruction.
abstract: OBJECTIVE
  Persistent weakness is a common problem after anterior cruciate ligament- (ACL-) reconstruction. This study investigated the effects of high-intensity (HRT) versus low-intensity (LRT) resistance training on leg extensor power and recovery of knee function after ACL-reconstruction.
  
  
  METHODS
  31 males and 19 females were randomized to HRT (n = 24) or LRT (n = 26) from week 8-20 after ACL-reconstruction. Leg extensor power, joint laxity, and self-reported knee function were measured before and 7, 14, and 20 weeks after surgery. Hop tests were assessed before and after 20 weeks.
  
  
  RESULTS
  Power in the injured leg was 90% (95% CI 86-94%) of the noninjured leg, decreasing to 64% (95% CI 60-69%) 7 weeks after surgery. During the resistance training phase there was a significant group by time interaction for power (P = 0.020). Power was regained more with HRT compared to LRT at week 14 (84% versus 73% of noninjured leg, resp.; P = 0.027) and at week 20 (98% versus 83% of noninjured leg, resp.; P = 0.006) without adverse effects on joint laxity. No other between-group differences were found.
  
  
  CONCLUSIONS
  High-intensity resistance training during rehabilitation after ACL-reconstruction can improve muscle power without adverse effects on joint laxity.
authors.affiliation: Musculoskeletal Rehabilitation Research Unit, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen, Bispebjerg Bakke 23, 2400 NV Copenhagen, Denmark ; Institute of Sports Medicine, Copenhagen, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen, Bispebjerg Bakke 23, 2400 NV Copenhagen, Denmark.
authors.forename: Theresa
authors.identifier: 0000-0001-9666-0027
authors.initials: T
authors.lastname: Bieler
authors.affiliation: Musculoskeletal Rehabilitation Research Unit, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen, Bispebjerg Bakke 23, 2400 NV Copenhagen, Denmark ; Institute of Sports Medicine, Copenhagen, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen, Bispebjerg Bakke 23, 2400 NV Copenhagen, Denmark.
authors.forename: Nanna Aue
authors.initials: NA
authors.lastname: Sobol
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen, Denmark.
authors.forename: Lars L
authors.initials: LL
authors.lastname: Andersen
authors.affiliation: Institute of Sports Medicine, Copenhagen, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen, Bispebjerg Bakke 23, 2400 NV Copenhagen, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Kiel
authors.affiliation: Institute of Sports Medicine, Copenhagen, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen, Bispebjerg Bakke 23, 2400 NV Copenhagen, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Løfholm
authors.affiliation: Institute of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark.
authors.forename: Per
authors.identifier: 0000-0002-9773-7361
authors.initials: P
authors.lastname: Aagaard
authors.affiliation: Musculoskeletal Rehabilitation Research Unit, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen, Bispebjerg Bakke 23, 2400 NV Copenhagen, Denmark ; Institute of Sports Medicine, Copenhagen, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen, Bispebjerg Bakke 23, 2400 NV Copenhagen, Denmark.
authors.forename: S Peter
authors.initials: SP
authors.lastname: Magnusson
authors.affiliation: Section for Sports Traumatology, Department of Orthopedic Surgery, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen, Bispebjerg Bakke 23, 2400 NV Copenhagen, Denmark.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Krogsgaard
authors.affiliation: Musculoskeletal Rehabilitation Research Unit, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen, Bispebjerg Bakke 23, 2400 NV Copenhagen, Denmark ; Institute of Sports Medicine, Copenhagen, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen, Bispebjerg Bakke 23, 2400 NV Copenhagen, Denmark.
authors.forename: Nina
authors.identifier: 0000-0001-5180-260X
authors.initials: N
authors.lastname: Beyer
mesh_terms: D000293:Adolescent; D000328:Adult; D059549:Anterior Cruciate Ligament Reconstruction / Q000534:rehabilitation*; D005081:Exercise Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D007866:Leg / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D020127:Recovery of Function