Department of Information Systems Creation, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama, Japan.
J Biomech. 2010 Mar 22;43(5):843-8. doi: 10.1016/j.jbiomech.2009.11.020. Epub 2009 Dec 14.
A four-wheeled walker is a valuable tool for assisting elderly persons with walking. The handgrip height is one of the most important factor determining the usefulness of the walker. However, the optimal handgrip height for elderly users has not been considered from a biomechanical viewpoint. In this study, the handgrip height was optimized by a two-dimensional mechanical model to reduce muscular loads in the lower body as well as in the upper body with various road conditions during steady walking. A critical height of the handgrip existed at 48% of the body height for the user regardless of gender and body dimension. A lower handgrip relieved muscular load for stooping users with a lower standing height. The stooping user pushed the handgrip strongly in the perpendicular direction by leaning the upper body on the walker. However, upright users with a higher standing height should use a four-wheeled walker with a higher handgrip for maintaining his or her upright posture. For downhill movement, the optimal handgrip height depended on the slope angle and the friction coefficient between the road and the wheels of the walker. On a low-friction downhill such as asphalt with a steeper slope angle, the user was required to maintain an erect trunk with a higher handgrip and to press on the handgrip strongly in the perpendicular direction. Movement on a low-friction road was easier for users on a flat road and an uphill road, but it compelled distinct effort from users when moving downhill.
四轮助行器是帮助老年人行走的重要工具。手柄高度是决定助行器实用性的最重要因素之一。然而，从生物力学的角度来看，老年人使用者的最佳手柄高度还没有得到考虑。在这项研究中，通过二维力学模型对手柄高度进行了优化，以在稳定行走时降低下肢和上肢的肌肉负荷，同时考虑了各种路面条件。对于使用者来说，手柄高度存在一个临界值，约为身高的 48%，与性别和身体尺寸无关。对于站立高度较低的弯腰使用者来说，较低的手柄高度可以减轻其肌肉负荷。弯腰使用者通过将上半身靠在助行器上，用力将手柄推向垂直方向。然而，站立高度较高的直立使用者为了保持直立姿势，应该使用手柄较高的四轮助行器。对于下坡运动，最佳手柄高度取决于坡度角度和助行器轮子与路面之间的摩擦系数。在坡度较陡的低摩擦下坡路面（如沥青路面）上，使用者需要用较高的手柄保持直立的躯干，并用力将手柄推向垂直方向。在平坦路面和上坡路面上，使用者的移动较为轻松，但在下坡路面上移动时，使用者需要付出明显的努力。
