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Author Ema, Ryoichi ♦ Wakahara, Taku ♦ Miyamoto, Naokazu ♦ Kanehisa, Hiroaki ♦ Kawakami, Yasuo
Source SpringerLink
Content type Text
Publisher Springer Berlin Heidelberg
File Format PDF
Copyright Year ©2013
Language English
Subject Domain (in DDC) Technology ♦ Medicine & health
Subject Keyword Cross-sectional area ♦ Muscle thickness ♦ Fascicle length ♦ Pennation angle ♦ Regional difference ♦ Human Physiology ♦ Occupational Medicine/Industrial Medicine ♦ Sports Medicine
Abstract This study aimed to clarify whether resistance training-induced changes in muscle architecture are homogeneous among the quadriceps and over different regions within each muscle.Eleven recreationally active men (27 ± 2 years) completed a 12-week resistance training program for knee extensors. Before and after the intervention, muscle thicknesses, fascicle lengths, and pennation angles of the four muscles (vastus lateralis, vastus medialis, vastus intermedius, rectus femoris) in several regions (2–4 regions per each muscle) were measured using ultrasonography. Anatomical cross-sectional areas (ACSAs) at the same positions as the ultrasound measurements were determined from magnetic resonance images.Relative increases in the ACSA, muscle thickness, and pennation angle of the rectus femoris were significantly greater than those of the vasti. Relative increases in the ACSAs of the vastus lateralis and rectus femoris were significantly greater in the distal than in the proximal region, and those in the muscle thickness and pennation angle of the vastus intermedius were significantly greater in the medial than in the lateral region. Fascicle lengths did not change in any muscles. The interrelations between muscle thickness and pennation angle remained unchanged after the intervention, with a significant association between the relative changes of the two variables.The current results indicate that (1) hypertrophy of the quadriceps femoris is associated with a proportional increase in pennation angle but not necessarily in fascicle length, and (2) training-induced changes in muscle size and pennation do not evenly occur among the quadriceps, along or across a muscle.
ISSN 14396319
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2013-08-15
Publisher Place Berlin/Heidelberg
e-ISSN 14396327
Journal European Journal of Applied Physiology
Volume Number 113
Issue Number 11
Page Count 13
Starting Page 2691
Ending Page 2703


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Source: SpringerLink