Document Detail

Quadricep and hamstring activation during drop jumps with changes in drop height.
MedLine Citation:
PMID:  21802039     Owner:  NLM     Status:  In-Data-Review    
OBJECTIVE: Compare the muscle activation patterns of the quadricep-hamstring during drop jumps with increasing demands of drop heights.
DESIGN: Observational.
SETTING: University biomechanics laboratory.
PARTICIPANTS: Fifteen male and eight female college physical education students.
MAIN OUTCOME MEASURES: Electromyographic activity of the rectus femoris (RF) and biceps femoris (BF) during the landing and takeoff phase of drop jumps from 20 to 60-cm heights. The ground contact time, vertical ground reaction force (vGRF), knee flexion angle during ground contact, and jump height after takeoff were also analyzed.
RESULTS: The activation of RF was higher in the drop jump from 60-cm than that from 20- and 30-cm (comparing 107.0±45.9 to 82.3±30.8 and 88.9±38.9 %MVIC, P<.05) during the landing phase. Activation of BF remained similar across all drop heights. Drop jump from 60-cm resulted in greater contact time during takeoff phase and peak vGRF, and resulted in greater maximum knee flexion but straighter knee at ground contact than from lower drop heights.
CONCLUSION: At drop height of 60-cm, the altered knee muscular activation and movement patterns may diminish the effectiveness of plyometric training and increase the potential injury risk of knee.
Hsien-Te Peng; Thomas W Kernozek; Chen-Yi Song
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Publication Detail:
Type:  Journal Article     Date:  2010-11-26
Journal Detail:
Title:  Physical therapy in sport : official journal of the Association of Chartered Physiotherapists in Sports Medicine     Volume:  12     ISSN:  1873-1600     ISO Abbreviation:  Phys Ther Sport     Publication Date:  2011 Aug 
Date Detail:
Created Date:  2011-08-01     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100940513     Medline TA:  Phys Ther Sport     Country:  England    
Other Details:
Languages:  eng     Pagination:  127-32     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Elsevier Ltd. All rights reserved.
Department of Physical Education, Chinese Culture University, Taipei, Taiwan.
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