 |
| Research article summary (published 7 Aug 2007): |
|
Free Full Text! See links below |
Age-related neuromuscular function during drop jumps.
Full Abstract
Muscle- and movement-specific fascicle-tendon interaction affects the performance of the neuromuscular system. This interaction is unknown among elderly and consequently contributes to the lack of understanding the age-related problems on neuromuscular control. The present experiment studied the age specificity of fascicle-tendon interaction of the gastrocnemius medialis (GM) muscle in drop jump (DJ) exercises. Twelve young and thirteen elderly subjects performed maximal squat jumps and DJs with maximal rebound effort on a sledge apparatus. Ankle and knee joint angles, reaction force, and electromyography (EMG) from the soleus (Sol), GM, and tibialis anterior (TA) muscles were measured together with the GM fascicle length by ultrasonography. The results showed that the measured ankle joint stiffness (AJS) during the braking phase correlated positively with the rebound speed in both age groups and that both parameters were significantly lower in the elderly than in young subjects. In both groups, the AJS correlated positively with averaged EMG (aEMG) in Sol during the braking phase and was further associated with GM activation (r = 0.55, P < 0.01) and TA coactivation (TA/GM r = -0.4 P < 0.05) in the elderly subjects. In addition, compared with the young subjects, the elderly subjects showed significantly lower GM aEMG in the braking phase and higher aEMG in the push-off phase, indicating less utilization of tendinous tissue (TT) elasticity. These different activation patterns are in line with the mechanical behavior of GM showing significantly less fascicle shortening and relative TT stretching in the braking phase in the elderly than in the young subjects. These results suggest that age-specific muscle activation patterns as well as mechanical behaviors exist during DJs.
Author information
Author/s: Hoffrén, M (M); Ishikawa, M (M); Komi, P V (PV);
Affiliation: Neuromuscular Research Center, Department of Biology of Physical Activity, University of Jyväskylä, 40014 Jyväskylä, Finland. merja.hoffren(-atsign-)sport.jyu.fi
Journal and publication information
Publication Type: Journal Article; Research Support, Non-U.S. Gov't
Journal: Journal of applied physiology (Bethesda, Md. : 1985) (J Appl Physiol), published in United States. (Language: eng)
Reference: 2007-Oct; vol 103 (issue 4) : pp 1276-83
Dates: Created 2007/10/05; Completed 2007/12/06; Revised 2008/11/21;
PMID: 17690197, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )
Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.
External Links for this article
(including full text providers, if available):
Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.
This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.
MeSH headings (categories)
This article was linked to the MESH Headings shown below.
Related articles
These are the highest related articles currently in the database:
- Is muscle power output a key factor in the age-related decline in physical performance? A comparison of muscle cross section, chair-rising test and jumping power.
30 Oct 2004 - Age-related differences in muscle power during single-step balance recovery. 30 Jul 2006
Related Article Map
10/30/2004
7/30/2006
Higher Relevance Score (24)
Lower Relevance Score (23)
Legend: 
- FREE Full text Article. - Abstract only. 
- Title only. More help.
See a large map of 100+ related articles.