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BioMed Research International
Volume 2014, Article ID 278512, 11 pages
http://dx.doi.org/10.1155/2014/278512
Clinical Study

The Effects of High-Intensity versus Low-Intensity Resistance Training on Leg Extensor Power and Recovery of Knee Function after ACL-Reconstruction

1Musculoskeletal Rehabilitation Research Unit, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen, Bispebjerg Bakke 23, 2400 NV Copenhagen, Denmark
2Institute of Sports Medicine, Copenhagen, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen, Bispebjerg Bakke 23, 2400 NV Copenhagen, Denmark
3National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen, Denmark
4Institute of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
5Section for Sports Traumatology, Department of Orthopedic Surgery, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen, Bispebjerg Bakke 23, 2400 NV Copenhagen, Denmark

Received 21 January 2014; Revised 24 March 2014; Accepted 28 March 2014; Published 27 April 2014

Academic Editor: Nicola A. Maffiuletti

Copyright © 2014 Theresa Bieler et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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 ( ) or LRT ( ) 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 ( ). Power was regained more with HRT compared to LRT at week 14 (84% versus 73% of noninjured leg, resp.; ) and at week 20 (98% versus 83% of noninjured leg, resp.; ) without adverse effects on joint laxity. No other between-group differences were found. Conclusion. High-intensity resistance training during rehabilitation after ACL-reconstruction can improve muscle power without adverse effects on joint laxity.