Document Detail


Neuromechanical strategies employed to increase jump height during the initiation of the squat jump.
MedLine Citation:
PMID:  15165601     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The maximal height attained in a vertical jump is heavily influenced by the execution of a large countermovement prior to the upward motion. When a jump must be executed without a countermovement, as in a squat jump, the maximal jump height is reduced. During such conditions, the human body may use other strategies in order to increase performance. The purpose of this research was to investigate the effects of two strategies employed during the initiation of the squat jump: the premovement silent period (PSP), and the small amplitude countermovement (SACM). Fifteen elite male volleyball players (20.6 +/- 1.6 years) and 13 untrained males (20.2 +/- 1.7 years) performed 10 maximal effort squat jumps from identical starting positions. The electromyographic activity of the vastus lateralis and biceps femoris was measured in conjunction with the vertical ground reaction force and vertical displacement. It was found that the presence of a PSP or a SACM of 1-3 cm did not increase maximal squat jump height significantly (p > 0.05), in neither the highly trained athletes nor the untrained individuals. These results suggest that these strategies do not play a major role in the determination of jump height. Researchers have assumed that a squat jump is purely concentric, and that there are no facilitating mechanisms present that may influence the performance of the jump. This study provides evidence to support this assumption.
Authors:
Christopher J Hasson; Eric L Dugan; Tim L A Doyle; Brendan Humphries; Robert U Newton
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology     Volume:  14     ISSN:  1050-6411     ISO Abbreviation:  J Electromyogr Kinesiol     Publication Date:  2004 Aug 
Date Detail:
Created Date:  2004-05-28     Completed Date:  2004-09-21     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9109125     Medline TA:  J Electromyogr Kinesiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  515-21     Citation Subset:  IM    
Affiliation:
Biomechanics Laboratory, Ball State University, Muncie, IN, USA. cjhasson@exsci.umass.edu
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MeSH Terms
Descriptor/Qualifier:
Adult
Analysis of Variance
Biomechanics
Electromyography
Humans
Locomotion / physiology*
Male
Movement
Muscle Contraction / physiology*
Muscle Fibers, Skeletal / physiology
Muscle, Skeletal / physiology
Signal Processing, Computer-Assisted
Sports / physiology
Videotape Recording
Weight-Bearing / physiology

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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