Zmitrewicz Robert J, Neptune Richard R, Sasaki Kotaro
Department of Mechanical Engineering, University of Texas at Austin, 1 University Station C2200, Austin, TX 78712, USA.
J Biomech. 2007;40(8):1824-31. doi: 10.1016/j.jbiomech.2006.07.009. Epub 2006 Oct 12.
Energy storage and return (ESAR) foot-ankle prostheses have been developed in an effort to improve gait performance in lower-limb amputees. However, little is known about their effectiveness in providing the body segment mechanical energetics normally provided by the ankle muscles. The objective of this theoretical study was to use muscle-actuated forward dynamics simulations of unilateral transtibial amputee and non-amputee walking to identify the contributions of ESAR prostheses to trunk support, forward propulsion and leg swing initiation and how individual muscles must compensate in order to produce a normal, symmetric gait pattern. The simulation analysis revealed the ESAR prosthesis provided the necessary trunk support, but it could not provide the net trunk forward propulsion normally provided by the plantar flexors and leg swing initiation normally provided by the biarticular gastrocnemius. To compensate, the residual leg gluteus maximus and rectus femoris delivered increased energy to the trunk for forward propulsion in early stance and late stance into pre-swing, respectively, while the residual iliopsoas delivered increased energy to the leg in pre- and early swing to help initiate swing. In the intact leg, the soleus, gluteus maximus and rectus femoris delivered increased energy to the trunk for forward propulsion in the first half of stance, while the iliopsoas increased the leg energy it delivered in pre- and early swing. Thus, the energy stored and released by the ESAR prosthesis combined with these muscle compensations was able to produce a normal, symmetric gait pattern, although various neuromuscular and musculoskeletal constraints may make such a pattern non-optimal.
为了改善下肢截肢者的步态表现，储能与回能（ESAR）脚踝假肢已被研发出来。然而，对于它们在提供通常由踝关节肌肉提供的身体节段机械能方面的有效性，人们了解甚少。本理论研究的目的是利用单侧经胫骨截肢者和非截肢者行走的肌肉驱动正向动力学模拟，来确定ESAR假肢对躯干支撑、向前推进和腿部摆动起始的贡献，以及各个肌肉必须如何进行补偿才能产生正常、对称的步态模式。模拟分析表明，ESAR假肢提供了必要的躯干支撑，但它无法提供通常由跖屈肌提供的躯干净向前推进力，也无法提供通常由双关节腓肠肌提供的腿部摆动起始力。为了进行补偿，残肢的臀大肌和股直肌分别在站立前期和站立后期至摆动前期为躯干提供更多能量以实现向前推进，而残肢的髂腰肌在摆动前期和摆动初期为腿部提供更多能量以帮助启动摆动。在健全的腿部，比目鱼肌、臀大肌和股直肌在站立的前半段为躯干提供更多能量以实现向前推进，而髂腰肌在摆动前期和摆动初期增加其为腿部提供的能量。因此，ESAR假肢储存和释放的能量与这些肌肉补偿相结合，能够产生正常、对称的步态模式，尽管各种神经肌肉和肌肉骨骼限制可能使这种模式并非最优。
