Knee flexor muscle responses under fatigue after harvesting the hamstrings for anterior cruciate ligament reconstruction. [corrected] (Journal article)

Ristanis, S./ Tsepis, E./ Giotis, D./ Zampeli, F./ Stergiou, N./ Georgoulis, A. D.

OBJECTIVE: To investigate if harvesting of semitendinosus (ST) and gracilis for anterior cruciate ligament (ACL) reconstruction will have an effect in coordinative firing pattern of the hamstrings under fatigue. We hypothesized that fatigue will increase the electromechanical delay (EMD) of the hamstrings on the harvested site and impair the synchronization between the medial and lateral hamstrings, in terms of muscle activity onsets. DESIGN: Prospective nonrandomized study. SETTING: Institutional. PATIENTS: Twelve ACL reconstructed patients with hamstrings, 2 years postoperatively. INTERVENTIONS: The patients performed a fatigue protocol with 25 continuous maximal isometric voluntary contractions of 8-second duration with 2-second intervals. MAIN OUTCOME MEASURES: The electromyography activity of biceps femoris (BF) and ST was recorded bilaterally and simultaneously with the torque measurements. The dependent variable examined was the EMD difference between BF and ST (muscle activation pattern). RESULTS: The fatigue protocol caused significant differences for the EMD values for both the intact and the reconstructed leg, demonstrating the influence of fatigue in EMD. However, the synchronization pattern between the medial and lateral hamstrings did not change significantly throughout the fatiguing protocol, revealing a balanced effect of fatigue. CONCLUSIONS: Although the EMD of ST and BF was significantly increased due to fatigue, as expected, their synchronization pattern as identified by the difference in their EMDs remained the same. Thus, the reconstructed knee responded in a balanced manner and the hamstrings firing pattern remained the same, despite the intervention to the ST tendon.
Institution and School/Department of submitter: Πανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών Υγείας. Τμήμα Ιατρικής
Keywords: Adolescent,Adult,Anterior Cruciate Ligament/*surgery,Electromyography,Humans,Isometric Contraction/physiology,Knee Injuries/rehabilitation/*surgery,Male,Muscle Fatigue/*physiology,Muscle, Skeletal/*physiology,Orthopedic Procedures/*methods,Range of Motion, Articular/physiology,*Tissue and Organ Harvesting,Young Adult
URI: https://olympias.lib.uoi.gr/jspui/handle/123456789/20530
ISSN: 1536-3724
Link: http://www.ncbi.nlm.nih.gov/pubmed/21694593
Appears in Collections:Άρθρα σε επιστημονικά περιοδικά ( Ανοικτά)

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