Optimal handgrip height of four-wheeled walker on various road conditions to reduce muscular load for elderly users with steady walking

• Published in: Journal of biomechanics Vol. 43; no. 5; pp. 843 - 848
• Main Author: Takanokura, Masato
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 22.03.2010; Elsevier; Elsevier Limited
• Subjects: Aged; Aged, 80 and over; Asphalt; Baggage; Biological and medical sciences; Biomechanics; Biomechanics. Biorheology; Computer Simulation; Computerized, statistical medical data processing and models in biomedicine; Female; Friction; Friction coefficient; Fundamental and applied biological sciences. Psychology; Gait - physiology; Hand Strength - physiology; Humans; Male; Man-Machine Systems; Mechanical model; Medical sciences; Models and simulation; Models, Biological; Movement; Muscle Contraction - physiology; Muscle, Skeletal - physiology; Muscular force; Muscular load; Optimization; Personal relationships; Physical Exertion - physiology; Physical Medicine and Rehabilitation; Roads; Slope; Studies; Tissues, organs and organisms biophysics; Trunks; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports; Walkers; Walking; Walking - physiology; Japan; Friction coefficient; Muscular force; Mechanical model; Baggage; Slope; Human; Muscle strength; Two dimensional model; Modeling; Biomechanics; Locomotion; Walking; Simulation model; Elderly; Biomedical engineering
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2009.11.020

Abstract 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.