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KMID : 0357220060180060001
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Journal of Korean Society Physical Therapy
2006 Volume.18 No. 6 p.1 ~ p.11
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Effects of Cooling on Repeated Muscle Contractions and Tendon Structures in Human
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Chae Su-Dong
Jung Myeong-Soo
Akira Horii
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Abstract
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Purpose: This study compared the effects of non-cold and cold conditions on the viscoelastic properties of tendon structures in vivo.
Methods: Seven male subjects perfomed plantar flesion exercise with maximal isokinetic voluntary contraction, which consisted of muscle contraction for 6 see and relaxation for 60 secs, 10 times for 1 set, Totally 10 sets were repeated. Before and after each task, the elongation of the tendon and aponeurosis of the medial gastrocnemius muscle (MG) was directly measured by ultrasonography. (The relationship between the estimated tendon force and tendon elongation.) Tendon cross-sectional area and ankle joint moment arm were obtained from magnetic resonance imaging (MRI). The tendon force was calculated from the joint moments and the tendon moment arm and stress was obtained by dividing force by cross-sectional areas (CSA). The strain was measured from the displacements normalized to tendon length.
Results: After cooling, the tendon force was larger in cold than non-cold. The value of the tendon stiffness of MVC were significantly higher under the cold condition than under the non-cold condition. The maximal strain and stress of $7.4{\pm}0.7%$ and $36.4{\pm}1.8$ MPa in non-cold and $7.8{\pm}8.5%,\;31.8{\pm}1.1$ MPa in cold (P<0.05).
Conclusions: This study shows for the first time that the muscle endurance in cooling increases the stiffness and Young’s modulus of human tendons. The improvement in muscle endurance with cooling was directly related to muscle and tendon.
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KEYWORD
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Tendon, Cooling, Ultrasonography, Muscle endurance
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