Mechanics of the Aging Achilles tendon with implications for walking performance

老化跟腱的力学对步行性能的影响

• 批准号: 8701027
• 负责人: Jason R Franz
• 金额: $ 5.46万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8701027
• 关键词: Adhesions; Adult; Affect; Age; Aging; Ankle; Attention; Behavior; Biomechanics; Computational Technique; Computer Simulation; Data; Deterioration; Elderly; Exhibits; Faculty; Fascicle; Fellowship; Gait; Gastrocnemius Muscle; Generations; Goals; Health; Human; Image; Impairment; Individual; Isotonic Exercise; Lateral; Lead; Length; Measures; Mechanics; Medial; Methods; Modeling; Morphology; Motion; Muscle; Muscle Fibers; Muscle Weakness; Musculoskeletal; Output; Performance; Phase; Play; Positioning Attribute; Postdoctoral Fellow; Quality of life; Research; Role; Simulate; Skeletal Muscle; Slide; Soleus Muscle; Techniques; Tendon structure; Time; Tissues; Training; Triceps Brachii Muscle; Ultrasonography; Universities; Walking; achilles tendon; age effect; age related; crosslink; elastography; experience; improved; in vivo; innovation; middle age; muscle form; muscle strength; novel; programs; public health relevance; sarcopenia; simulation; skills; stem; transmission process; young adult

DESCRIPTION (provided by applicant): The pervasive decline in ankle power generation, even in otherwise healthy older adults, plays a central role in the deterioration of walking abilit with age. However, muscle strengthening alone generally fails to significantly improve the walking ability of older adults, suggesting that factors other than sarcopenia contribute to the decline in plantarflexor power with age. I propose to investigate the relevance of age-related changes in Achilles tendon mechanics and their implications for walking ability in older adults. The premise of this study is that the aging Achilles tendon exhibits altered in vivo behavior that greatly diminishes the ability to optimally coordinate the ankle plantarflexor muscles during the push-off phase of gait. Preliminary data suggest that the superficial and deep Achilles tendon fascicles exhibit distinctly different displacements, likely due to inter- fascicle sliding, which ay be critical for optimally coordinating the forces from the individual plantarflexor muscles. Moreover, these data show evidence that advancing age brings much more uniform tendon tissue motion, which may arise from inter-fascicle adhesions within the Achilles tendon. The overall hypothesis of this research is that greater fascicle adhesions within the Achilles tendon of older adults bring more uniform tendon deformations that reduce the capacity for optimally coordinating the individual plantarflexor muscles, thereby compromising plantarflexor power and thus gait performance. The approach utilizes novel advances in imaging biomechanics and computational modeling to investigate age-related changes in Achilles tendon mechanics and function, and to predict the ramifications for walking ability in older adults. Following are the specific aims. Aim 1 will use an advanced ultrasound elastography approach to determine if advancing age is accompanied by greater Achilles tendon strain uniformity, a potentially important factor to consider as a mechanism for age- related walking ability limitations. Aim 2 will use an innovative combination of ultrasound elastography and electrical muscle stimulation to reveal if greater fascicle adhesions within the Achilles tendon of older adults bring more uniform deformations between the deep and superficial portions of the tendon. Finally, Aim 3 will incorporate the findings from Aims 1 and 2 into muscle-actuated forward dynamic simulations to predict changes in plantarflexor function during walking in older adults. This research will investigate for the first time the age-related changes in localized Achilles tendon strain distributions (Aim 1), their underlying mechanisms (Aim 2), and the ramifications for walking ability in older adults (Aim 3). Successful completion of these aims will contribute to an enhanced scientific understanding of age-related declines in walking ability and point to specific opportunities where more appropriate therapies could prolong independence and thus enhance quality of life in older adults.

描述（由申请人提供）：即使在其他方面健康的老年人中，脚踝发电能力的普遍下降也是步行能力随年龄下降的主要原因。然而，仅靠肌肉强化通常无法显着改善老年人的步行能力，这表明除了肌肉减少症之外，还有其他因素导致跖屈肌力量随着年龄的增长而下降。我建议研究跟腱力学与年龄相关的变化的相关性及其对老年人步行能力的影响。这项研究的前提是，老化的跟腱表现出体内行为的改变，这极大地削弱了在步态的推出阶段最佳协调踝关节跖屈肌的能力。初步数据表明，浅层和深层跟腱束表现出明显不同的位移，可能是由于束间滑动所致，这对于最佳协调各个跖屈肌的力量至关重要。此外，这些数据表明，年龄增长会带来更加均匀的肌腱组织运动，这可能是由于跟腱内的束间粘连引起的。这项研究的总体假设是，老年人跟腱内较大的肌束粘连会带来更均匀的肌腱变形，从而降低最佳协调各个跖屈肌的能力，从而损害跖屈肌的力量和步态表现。该方法利用成像生物力学和计算模型方面的新进展来研究跟腱力学和功能与年龄相关的变化，并预测老年人步行能力的影响。以下是具体目标。目标 1 将使用先进的超声弹性成像方法来确定年龄的增长是否伴随着更大的跟腱应变均匀性，这是一个需要考虑的潜在重要因素，作为与年龄相关的步行能力限制的机制。目标 2 将使用超声弹性成像和肌肉电刺激的创新组合来揭示老年人跟腱内较大的肌束粘连是否会带来肌腱深层和浅层部分之间更均匀的变形。最后，目标 3 将把目标 1 和 2 的发现纳入肌肉驱动的前向动态模拟中，以预测老年人行走期间跖屈肌功能的变化。这项研究将首次调查局部跟腱应变分布与年龄相关的变化（目标 1）、其潜在机制（目标 2）以及对老年人步行能力的影响（目标 3）。成功完成这些目标将有助于增强对与年龄相关的步行能力下降的科学认识，并指出更合适的治疗可以延长独立性的具体机会，从而提高老年人的生活质量。