Effect of chronic unloading and rehabilitation on human Achilles tendon properties: a velocity-encoded phase-contrast MRI study.
Effect of chronic unloading and rehabilitation on human Achilles tendon properties: a velocity-encoded phase-contrast MRI study.
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慢性卸载和康复对人类跟腱特性的影响：速度编码相位对比 MRI 研究。
DOI：
10.1152/japplphysiol.90699.2008
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Sinha,Shantanu
中科院分区：
文献类型：
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作者：
Shin,Dongsuk;Finni,Taija;Ahn,Sinyeob;Hodgson,JohnA;Lee,Hae-Dong;Edgerton,VReggie;Sinha,Shantanu
本研究的目的是测量和监测跟腱的力学性能和小腿三头肌肌肉的产力能力的变化后，4周的肢体悬吊和6周的物理康复。5名健康志愿者接受单侧下肢悬吊，然后每周进行一次物理治疗。一个速度编码，相位对比磁共振成像（VE-PC-MRI）技术被用来估计肌腱应变的功能，在次最大等长收缩产生的力。肢体悬吊后小腿三头肌肌力下降至悬吊前水平的53.2 ± 15.6%（均数±标准差）（P< 0.05）。根据肌腱应力-应变关系的斜率估计的杨氏模量降低了17.1%（从140.50 ± 29.33降至119.95 ± 36.07 MPa，P< 0.05），而反映“趾部”的肌腱过渡点增加了55.7%（从2.2 ± 1.0%增至3.4 ± 1.24%）。肌肉力量，肌腱刚度，和过渡点恢复到presuspension水平，6周的康复结束。跟骨在等长收缩时的位移量占肌腱位移量的52.13 ± 7.63%。从解剖磁共振轴向图像确定的肌腱横截面积保持不变，表明肌腱弹性模量和转变点的改变主要是由于材料退化。通过VE-PC-MRI技术测量的慢性卸载后转变点的增加以前没有报道，并提供了新的见解，可能发生在肌腱卷曲结构的生物力学变化。
The objective of this study was to measure and monitor changes in Achilles tendon mechanical properties and force production capability of triceps surae muscles after 4 wk of limb suspension and 6 wk of physical rehabilitation. Five healthy volunteers underwent unilateral lower limb suspension followed by weekly physiotherapy. A velocity-encoded, phase-contrast magnetic resonance imaging (VE-PC-MRI) technique was used to estimate the tendon strain as a function of force produced during the submaximal isometric contractions. After limb suspension, triceps surae muscle strength decreased to 53.2 ± 15.6% (mean ± SD) of the presuspension level (P< 0.05). Young's modulus, estimated from the slope of the tendon stress-strain relationship, decreased by 17.1% (from 140.50 ± 29.33 to 119.95 ± 36.07 MPa,P< 0.05), while the tendon transition point, reflecting the “toe region,” increased by 55.7% (from 2.2 ± 1.0% to 3.4 ± 1.24%). Muscle strength, tendon stiffness, and transition point recovered to presuspension levels by the end of 6 wk of rehabilitation. Calcaneus movement was significant during the “isometric” contraction, accounting for 52.13 ± 7.63% of the tendon displacement. Tendon cross-sectional area determined from anatomic magnetic resonance axial images remained unchanged, suggesting that the altered tendon elastic modulus and transition point were largely due to material deterioration. The increase in the transition point following chronic unloading as measured by the VE-PC-MRI technique has not been previously reported and offers new insights into the biomechanical changes that may occur in the tendon crimp structure.