Vistamehr Arian, Kautz Steven A, Neptune Richard R
Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, USA.
Department of Health Sciences and Research, Medical University of South Carolina, Charleston, SC, USA; Ralph H Johnson VA Medical Center, Charleston, SC, USA.
Clin Biomech (Bristol). 2014 May;29(5):583-9. doi: 10.1016/j.clinbiomech.2014.02.007. Epub 2014 Mar 7.
In post-stroke hemiparetic subjects, solid polypropylene ankle-foot-orthoses are commonly prescribed to assist in foot clearance during swing while bracing the ankle during stance. Mobility demands, such as changing walking speed and direction, are accomplished by accelerating or decelerating the body and maintaining dynamic balance. Previous studies have shown that the ankle plantarflexors are primary contributors to these essential biomechanical functions. Thus, with ankle-foot-orthoses limiting ankle motion and plantarflexor output during stance, execution of these walking subtasks may be compromised. This study examined the influence of a solid polypropylene ankle-foot-orthosis on forward propulsion and dynamic balance in healthy adults.
Kinematic and kinetic data were recorded from 10 healthy adults walking with and without a unilateral ankle-foot-orthosis at steady-state slow (0.6m/s) and moderate (1.2m/s) speeds, and during accelerated (0-1.8m/s at 0.06m/s(2)) and decelerated (1.8-0m/s at -0.06m/s(2)) walking. Propulsion was quantified by propulsive and braking impulses (i.e., time integral of the anterior-posterior ground reaction force) while dynamic balance was quantified by the peak-to-peak range of whole-body angular momentum.
The propulsive impulses decreased in the leg with ankle-foot-orthosis compared to the contralateral leg and no ankle-foot-orthosis condition. Further, the ankle-foot-orthosis resulted in a greater range of angular momentum in both the frontal and sagittal planes, which were correlated with the reduced peak hip abduction and reduced ankle plantarflexor moments, respectively.
Solid ankle-foot-orthoses limit the successful execution of important mobility subtasks in healthy adults and that the prescription of ankle-foot-orthosis should be carefully considered.
在中风后偏瘫患者中，通常会开具坚固的聚丙烯踝足矫形器，以在摆动期辅助足部离地，同时在站立期支撑脚踝。诸如改变步行速度和方向等移动需求，是通过身体加速或减速并维持动态平衡来实现的。先前的研究表明，踝跖屈肌是这些重要生物力学功能的主要贡献者。因此，由于踝足矫形器在站立期限制了踝关节活动和跖屈肌输出，这些步行子任务的执行可能会受到影响。本研究探讨了坚固的聚丙烯踝足矫形器对健康成年人向前推进和动态平衡的影响。
记录了10名健康成年人在佩戴和不佩戴单侧踝足矫形器的情况下，以稳态慢速（0.6米/秒）和中速（1.2米/秒）行走时，以及在加速（从0至1.8米/秒，加速度为0.06米/秒²）和减速（从1.8至0米/秒，减速度为-0.06米/秒²）行走时的运动学和动力学数据。通过推进和制动冲量（即前后地面反作用力的时间积分）来量化推进力，而通过全身角动量的峰峰值范围来量化动态平衡。
与对侧腿和无踝足矫形器的情况相比，佩戴踝足矫形器的腿的推进冲量降低。此外，踝足矫形器导致在额面和矢状面的角动量范围更大，这分别与髋外展峰值降低和踝跖屈力矩降低相关。
坚固的踝足矫形器会限制健康成年人重要移动子任务的成功执行，应谨慎考虑踝足矫形器的处方。
