Tendon properties and muscle architecture for knee extensors and plantar flexors in boys and men.
BACKGROUND
The purpose of this study was to compare the elastic properties and size of tendinous structures and muscle architecture for knee extensors and plantar flexors in boys and men.


METHODS
Twenty-two early pubescent boys (9.6-12.7yrs) and 23 young adult men (19.8-26.2yrs) participated in this study. The maximal strain and thickness of tendinous structures for knee extensors and plantar flexors were measured using ultrasonography. In addition, the fascicle lengths of vastus lateralis and medial gastrocnemius muscles were measured.


RESULTS
The maximal strain of tendinous structures for plantar flexors was significantly greater in boys than in men, while there was no difference in the maximal strain for knee extensors between the two groups. The relative thickness (to body mass(1/3)) of Achilles tendon was significantly greater in boys than in men, although there was no difference in that of patellar tendon between the two groups. The relative fascicle length (to limb length) of vastus lateralis muscle was significantly lower in boys than in men, although there was no difference in that of medial gastrocnemius muscle between the two groups.


CONCLUSIONS
These results suggest that the amount of changes in the elastic properties and sizes of tendinous structures and in the fascicle lengths from early pubescence to maturity is different for different muscle groups (in particular, the knee extensors and the plantar flexors).
Department of Life Science, University of Tokyo, Meguro, Tokyo, Japan. Electronic address: kubo@idaten.c.u-tokyo.ac.jp.
Keitaro
K
Kubo
Department of Physical Education, Kokushikan University, Tokyo, Japan.
Takanori
T
Teshima
Department of Physical Education, Kokushikan University, Tokyo, Japan.
Toshihiro
T
Ikebukuro
Faculty of Sports Sciences, Waseda University, Tokorozawa, Saitama, Japan.
Norikazu
N
Hirose
Department of Physical Education, Kokushikan University, Tokyo, Japan.
Naoya
N
Tsunoda
D000125:Achilles Tendon / Q000033:anatomy & histology*; D000328:Adult; D000367:Age Factors; D001696:Biomechanical Phenomena / Q000502:physiology; D002648:Child; D004548:Elasticity / Q000502:physiology*; D005528:Foot / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000502:physiology*; D052097:Quadriceps Muscle / Q000502:physiology; D013710:Tendons / Q000033:anatomy & histology / Q000502:physiology*; D055815:Young Adult
Fascicle length; Strain; Thickness; Ultrasonography