Document Detail

The effect of heavy- vs. light-load jump squats on the development of strength, power, and speed.
MedLine Citation:
PMID:  11834109     Owner:  NLM     Status:  MEDLINE    
The purpose of this investigation was to examine the effect of an 8-week training program with heavy- vs. light-load jump squats on various physical performance measures and electromyography (EMG). Twenty-six athletic men with varying levels of resistance training experience performed sessions of jump squats with either 30% (JS30, n = 9) or 80% (JS80, n = 10) of their one repetition maximum in the squat (1RM) or served as a control (C, n = 7). An agility test, 20-m sprint, and jump squats with 30% (30J), 55% (55J), and 80% (80J) of their 1RM were performed before and after training. Peak force, peak velocity (PV), peak power (PP), jump height, and average EMG (concentric phase) were calculated for the jumps. There were significant increases in PP and PV in the 30J, 55J, and 80J for the JS30 group (p <or= 0.05). The JS30 group also significantly increased in the 1RM with a trend towards improved 20-m sprint times. In contrast, the JS80 group significantly increased both PF and PP in the 55J and 80J and significantly increased in the 1RM but ran significantly slower in the 20-m sprint. In the 30J the JS30 group's percentage increase in EMG activity was significantly different from the C group. In the 80J the JS80 group's percentage increase in EMG activity was significantly different from the C group. This investigation indicates that training with light-load jump squats results in increased movement velocity capabilities and that velocity-specific changes in muscle activity may play a key role in this adaptation.
Jeffrey M McBride; Travis Triplett-McBride; Allan Davie; Robert U Newton
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Publication Detail:
Type:  Clinical Trial; Comparative Study; Controlled Clinical Trial; Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of strength and conditioning research / National Strength & Conditioning Association     Volume:  16     ISSN:  1064-8011     ISO Abbreviation:  J Strength Cond Res     Publication Date:  2002 Feb 
Date Detail:
Created Date:  2002-02-08     Completed Date:  2002-03-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9415084     Medline TA:  J Strength Cond Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  75-82     Citation Subset:  IM    
Southern Cross University, School of Exercise Science and Sport Management, Lismore, NSW, Australia.
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MeSH Terms
Adaptation, Physiological / physiology
Exercise / physiology*
Longitudinal Studies
Muscle, Skeletal / physiology*
Physical Education and Training / methods*
Running / physiology
Task Performance and Analysis
Thigh / anatomy & histology
Time Factors
Weight Lifting / physiology*

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

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