Journal of Applied Physiology AJP: Cell Physiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
 QUICK SEARCH:   [advanced]


     


J Appl Physiol (December 4, 2008). doi:10.1152/japplphysiol.90776.2008
This Article
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
106/2/539    most recent
90776.2008v1
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Galindo, A.
Right arrow Articles by Nicol, C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Galindo, A.
Right arrow Articles by Nicol, C.
Submitted on June 17, 2008
Revised on December 1, 2008
Accepted on December 1, 2008

Neuromuscular control in landing from supra-maximal dropping height

Amandine Galindo1*, Joelle Barthelemy2, Masaki Ishikawa3, Pascale Chavet2, Vincent Martin4, Janne Avela5, Paavo V. Komi5, and Caroline Nicol2

1 Universtity of Jyväskylä
2 Institute of Movement Sciences
3 Neuromuscular Research Center
4 Universite d'Evry - Val d'Essonne/Genopole
5 University of Jyvaskyla

* To whom correspondence should be addressed. E-mail: amandine.galindo{at}yahoo.fr.

The present study utilized high impact supra-maximal landings to examine the influence of the pre-impact force level on the post-impact electromyographic (EMG) activity and, in particular, on the short latency EMG reflex (SLR) component. Unilateral-leg landings were performed in a sitting position on a sledge apparatus after release from high, but individually constant dropping height. A lower limb guiding device fixed to the front of the sledge seat allowed the subjects to sustain a given pre-set force level up to impact. This force level was either freely chosen or set at 20, 35 and 50% of maximal isometric plantarflexion force. EMG activity was recorded from eight major lower limb muscles. It was expected that the increase in the pre-impact force level would require the intervention of a protective neural strategy during the post-impact phase that would attenuate the SLR amplitude. The ultrasonography recordings confirmed that the SOL fascicles were stretched to induce SLR. The main finding was the similarity across all tested conditions of the impact peak force and post-impact EMG activity, including the SLR response. Both observations are mostly attributed to the similar EMG levels and close force levels reached towards impact. The instruction to maintain a given pre-set force level was indeed overruled when getting close to impact. It is suggested that, in the present supra-maximal landing condition, a protective central neural strategy did occur that took into account the pre-set force level in order to secure similar impact loads.







HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Visit Other APS Journals Online
Copyright © 1948 by the American Physiological Society.