Int J Sports Med 2009; 30(8): 614-623
DOI: 10.1055/s-0029-1214379
Training & Testing

© Georg Thieme Verlag KG Stuttgart · New York

Neuromuscular Fatigue after Resistance Training

M. Izquierdo 1 , J. Ibañez 1 , J. A. L. Calbet 2 , M. González-Izal 1 , I. Navarro-Amézqueta 1 , C. Granados 1 , A. Malanda 3 , F. Idoate 4 , J. J. González-Badillo 5 , K. Häkkinen 6 , W. J. Kraemer 7 , I. Tirapu 1 , E. M. Gorostiaga 1
  • 1Studies, Research and Sport Medicine Center, Government of Navarre, Spain
  • 2Department of Physical Education, University of Las Palmas of Gran Canaria, Spain
  • 3Department of Electric and Electronic Engineering, Public University of Navarre, Spain
  • 4Department of Radiology, Clinic of San Miguel, Navarre, Spain
  • 5Department of Physical Education and Computer Sciences, University Pablo of Olavide, Sevilla, Spain
  • 6Department of Biology of Physical Activity, University of Jyväskylä, Finland
  • 7Department of Kinesiology, Human Performance Laboratory, University of Connecticut, Storrs, CT, USA
Weitere Informationen

Publikationsverlauf

accepted after revision February 9, 2009

Publikationsdatum:
20. April 2009 (online)

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Abstract

This study examined the effects of heavy resistance training on dynamic exercise-induced fatigue task (5×10RM leg-press) after two loading protocols with the same relative intensity (%) (5×10RMRel) and the same absolute load (kg) (5×10RMAbs) as in pretraining in men (n=12). Maximal strength and muscle power, surface EMG changes [amplitude and spectral indices of muscle fatigue], and metabolic responses (i.e.blood lactate and ammonia concentrations) were measured before and after exercise. After training, when the relative intensity of the fatiguing dynamic protocol was kept the same, the magnitude of exercise-induced loss in maximal strength was greater than that observed before training. The peak power lost after 5×10RMRel (58–62%, pre-post training) was greater than the corresponding exercise-induced decline observed in isometric strength (12–17%). Similar neural adjustments, but higher accumulated fatigue and metabolic demand were observed after 5×10RMRel. This study therefore supports the notion that similar changes are observable in the EMG signal pre- and post-training at fatigue when exercising with the same relative load. However, after training the muscle is relatively able to work more and accumulate more metabolites before task failure. This result may indicate that rate of fatigue development (i.e. power and MVC) was faster and more profound after training despite using the same relative intensity.

References

Correspondence

Dr. M. Izquierdo

Gobierno de Navarra

Centro de Estudios, Investigación y Medicina del Deporte

C/Sangüesa 34

31005 Pamplona

Spain

Telefon: +34/94/829 26 23

Fax: +34/94/829 26 36

eMail: mikel.izquierdo@ceimd.org