Passive and active muscle stiffness in plantar flexors of long distance runners.
The aim of the present study was to compare passive and active muscle stiffness and tendon stiffness between long distance runners and untrained men. Twenty long distance runners and 24 untrained men participated in this study. Active muscle stiffness in the medial gastrocnemius muscle was calculated according to changes in estimated muscle force and fascicle length during fast stretching after submaximal isometric contractions. Passive muscle stiffness was also calculated from estimated passive muscle force and fascicle length during slow passive stretching. Tendon stiffness was determined during isometric plantar flexion by ultrasonography. Passive muscle stiffness of long distance runners was significantly higher than that of untrained men (p<0.001). Active muscle stiffness at all torque levels of long distance runners was also significantly higher than that of untrained men (p<0.001). No significant difference was observed in tendon stiffness between long distance runners and untrained men (p=0.869). These results suggested that passive and active muscle stiffness were higher in long distance runners than in untrained men, whereas no significant difference was observed in tendon stiffness between the two groups.
Department of Life Science, The University of Tokyo, Komaba 3-8-1, Meguro, Tokyo 153-8902, Japan. Electronic address: kubo@idaten.c.u-tokyo.ac.jp.
Keitaro
K
Kubo
Faculty of Physical Education, Kokushikan University, Tokyo, Japan.
Daisuke
D
Miyazaki
Faculty of Physical Education, Kokushikan University, Tokyo, Japan.
Kenji
K
Yamada
Sports Science Laboratory, Wako University, Machida, Tokyo, Japan.
Hideaki
H
Yata
Faculty of Physical Education, Kokushikan University, Tokyo, Japan.
Shozo
S
Shimoju
Faculty of Physical Education, Kokushikan University, Tokyo, Japan.
Naoya
N
Tsunoda
D000328:Adult; D004576:Electromyography; D005528:Foot; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000502:physiology*; D009142:Musculoskeletal Physiological Phenomena; D012420:Running / Q000502:physiology*; D013710:Tendons / Q000000981:diagnostic imaging / Q000502:physiology*; D019415:Torque; D014463:Ultrasonography; D055815:Young Adult
Fascicle; Tendon; Ultrasonography