gms | German Medical Science

Deutscher Kongress für Orthopädie und Unfallchirurgie
72. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 94. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie und 49. Tagung des Berufsverbandes der Fachärzte für Orthopädie und Unfallchirurgie

22. - 25.10.2008, Berlin

Effects of exercise intensity on muscle recruitment patterns in anterior cruciate ligament reconstructed soccer players

Meeting Abstract

  • A. Georgoulis - Orhopädische Klinik, Medizinische Fakultät, Universität Ioannina, Ioannina, Greece
  • K. Patras - Orhopädische Klinik, Medizinische Fakultät, Universität Ioannina, Ioannina, Greece
  • G. Ziogas - Orhopädische Klinik, Medizinische Fakultät, Universität Ioannina, Ioannina, Greece
  • S. Ristanis - Orhopädische Klinik, Medizinische Fakultät, Universität Ioannina, Ioannina, Greece
  • N. Stergiou - HPER Biomechanics Laboratory, University of Nebraska at Omaha, Omaha, United States of America

Deutscher Kongress für Orthopädie und Unfallchirurgie. 72. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 94. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie, 49. Tagung des Berufsverbandes der Fachärzte für Orthopädie. Berlin, 22.-25.10.2008. Düsseldorf: German Medical Science GMS Publishing House; 2008. DocWI76-1590

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dkou2008/08dkou483.shtml

Veröffentlicht: 16. Oktober 2008

© 2008 Georgoulis et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

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Objectives: Recent studies have shown that the neuromuscular response to fatiguing exercise, following ACL reconstruction, is altered. The aim of the present study was to evaluate the neuromuscular response at discrete intensity levels. We hypothesized that the neuromuscular response of the reconstructed leg will differ from that of the intact leg at exercise of heavy but not of moderate intensity.

Methods: We evaluated 9 ACLR soccer players 1-3 years post-operatively. ACLR players had anterior tibial translation difference between reconstructed and intact leg less than 2mm, Tegner activity score 8 and Lysholm score 99. Subjects performed a GXT treadmill running test to determine blood lactate response and maximal oxygen uptake. Two 10-min run were performed, one at moderate intensity and one at heavy intensity that were selected from the GXT test. During the bouts gas exchange data and heart rate were collected continuously and blood lactate was measured pre- and post-exercise. EMG data were recorded for 15 seconds at the 3rd and 10th minute from 3 muscles (vastus lateralis, biceps femoris and medial gastrocnemius) bilaterally with a telemetric EMG system. The dependent variable examined was the average peak EMG amplitude. T-tests where used to compare the values at minute 3 and 10 for each muscle for both intact and reconstructed leg.

Results: For the moderate bout, baseline and end-exercise lactate values were 2.0(0.3) and 2.4(0.4) mM. End-exercise VO2 values did not differ from VO2 at min 3 [32.2(1.7) vs 30.5(3.0) ml/min/kg, p 0.05]. For the heavy bout, baseline and end-exercise lactate values were 2.2(0.3) and 7.3(1.7) mM. End-exercise VO2 values were significantly higher compared to min 3 [49.1(3.6) vs 44.8(3.1) ml/min/kg, p0.05]. For the heavy bout there was a significant increase in the peak EMG amplitude for the intact leg 236.6(103.2) vs 243.7(114.8) mV, p0.05 with no difference for the ACLR leg 227.0(145.3) vs 213.2(118.2) mV, p0.05. The moderate bout had no effect on the EMG amplitude for both legs. Biceps femoris and medial gastrocnemius were not affected by either bout.

Conclusions: The major finding was that during heavy exercise, fatigue as evidenced by a significant rise in VO2 and blood lactate, was compensated for by an increase in the EMG amplitude of the VL for the intact leg, but no alterations were noted for the reconstructed leg. Our results may indicate an inability of the ACL reconstructed leg to progressively recruit muscle fibers since increases in EMG amplitude have been associated with recruitment of more fibers to compensate for fatigue. Previous studies indicate that ACLR subjects demonstrate normal EMG patterns during non-fatiguing activities such as walking. It appears that fatigue may modify these patterns.