Document Detail

The effect of the oral contraceptive pill on the passive stiffness of the human gastrocnemius muscle in vivo.
MedLine Citation:
PMID:  23445919     Owner:  NLM     Status:  In-Data-Review    
The aim of this investigation was to determine the effect of sustained monophasic oral contraceptive pill (MOCP) use on the in vivo passive stiffness of the gastrocnemius medialis (GM) muscle-tendon unit. Twenty four females volunteered for this study (age range 20-25 yrs); twelve participants had been taking the combined MOCP for a minimum of 12 months, and twelve participants, who had never taken the MOCP, formed a control group. Distal displacement of the GM myotendinous junction (MTJ) was measured during passive dorsiflexion at 2 Nm increments to 20 Nm, and at end range of motion using ultrasonography. In addition, GM MTJ displacement was measured at passive torques equivalent to 5, 10 and 15% of plantarflexion maximal voluntary contraction (MVC) torque, and relative to GM length. MOCP users had significantly greater GM MTJ displacement at all passive torques (P<0.01), reaching 40% more at 20 Nm; these displacements remained significantly different when MVC and GM length were accounted for (P<0.01). Passive muscle stiffness from 0-20 Nm was 31% less in MOCP users compared to non-users (P<0.01). In conclusion, based on the in vivo assessment of GM MTJ displacement, passive muscle stiffness is less in MOCP using females, compared to non-pill users.
C I Morse; J Spencer; A W Hussain; G L Onambele
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of musculoskeletal & neuronal interactions     Volume:  13     ISSN:  1108-7161     ISO Abbreviation:  J Musculoskelet Neuronal Interact     Publication Date:  2013 Mar 
Date Detail:
Created Date:  2013-02-28     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101084496     Medline TA:  J Musculoskelet Neuronal Interact     Country:  Greece    
Other Details:
Languages:  eng     Pagination:  97-104     Citation Subset:  IM    
Institute for Performance Research, Department of Exercise and Sport Science, Manchester Metropolitan University Cheshire, United Kingdom.
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