Original articles  SPORT INJURIES AND REHABILITATION 

The Journal of Sports Medicine and Physical Fitness 2003 June;43(2):180-8

Copyright © 2009 EDIZIONI MINERVA MEDICA

lingua: Inglese

The effects of ACL injury on lower extremity activation during closed kinetic chain exercise

Heller B. M. ¹, Pincivero D. M. ²

¹ Department of Physical Therapy Andrews University, Berrien Springs, MI, USA 2 Department of Kinesiology The University of Toledo, Toledo, OH, USA

Aim. ­Injury to the ante­rior cru­ciate lig­a­ment (ACL) has ­been sug­gested to ­alter the neu­ro­mus­cular mech­a­nism in the ­lower ­extremity. How­ever, con­clu­sive evi­dence ­regarding ­this occur­rence has yet to be estab­lished ­during ­closed ­kinetic ­chain exer­cise. The pur­pose of ­this ­study was to ­assess dif­fer­ences in ­muscle acti­va­tion ­during slide­board exer­cise ­between non-­injured, ACL defi­cient, and ACL recon­structed indi­vid­uals.
­Methods. Experi­mental ­design: com­par­a­tive ­study. Set­ting: ­research labor­a­tory. Par­tic­i­pants: sub­jects for ­this ­study ­included 10 ­healthy, non-­injured (NI) indi­vid­uals, 7 uni-lat­eral ACL defi­cient (­ACLD) indi­vid­uals, and 6 uni-lat­eral ACL recon­structed (­ACLR) indi­vid­uals. Inter­ven­tions: EMG ­activity was meas­ured ­from the ­vastus medi­alis (VM), ­vastus lat­er­alis (VL), ­medial ham­string (MH), lat­eral ham­string (LH), tibi­alis ante­rior (TA), and ­medial gas­troc­ne­mius (MG) mus­cles ­during slide­board per­for­mance. Meas­ures: EMG for ­each ­muscle ­during ­each of 6 ­phases of 1 ­average slide­board ­cycle was ­expressed as a per­centage of EMG ­during a max­imal vol­un­tary con­trac­tion.
­Results. The ­results dem­on­strated ­that ­during slide­board ­phase I the VM, VL, and TA mus­cles gen­er­ated the ­greatest ­amount of ­activity as com­pared to the ­other mus­cles. ­Vastus medi­alis ­muscle acti­va­tion was ­found to be sig­nif­i­cantly ­higher ­than the ­other mus­cles in the ­involved/dom­i­nant ­limb, as com­pared to the non-­involved/non-dom­i­nant ­limb ­during slide­board ­phase II. ­During slide­board ­phases III-VI, tibi­alis ante­rior ­muscle acti­va­tion was ­found to be con­sis­tently ­higher ­than the ­other mus­cles, ­while ham­string ­muscle ­activity was con­sis­tently the ­lowest.
Con­clu­sion. It is con­cluded ­that adap­tive ­changes fol­lowing ACL ­injury ­during a ­dynamic, ­closed ­kinetic ­chain ­activity ­such as the slide­board exer­cise, may be a res­to­ra­tion of a bi-lat­eral bal­ance in ­muscle acti­va­tion.