Stress in the Lower Extremities Due to Walking Stairs One Step at a Time / 体力科学

ABSTRACT

The purpose of this study was to determine the differences between walking stairs one step at a time versus using alternating feet by evaluating muscle tensions and joint forces. This quantitative basic knowledge will be useful in setting safe guidelines for stair walking in rehabilitation programs. Five healthy young males participated as subjects. Ascending and descending motions were measured by utilizing a 3 D motion analysis system, a force platform and an EMG telemetry system. Measurements were made for three conditions 1) Both limbs during alternating feet walking (normal stair walking NW), 2) The leading limb (LL) and 3) The trailing limb (TL) when walking stairs one step at a time. Moments of force on the joints, muscle tensions and joint forces were calcu-lated using two mathematical models (the link segment and musculoskeletal models, Yamazaki (1992) ) . When ascending, maximum flexion angles of three joints in the TL were smaller than during NW. Also, quadriceps tension in the TL and soleus tension in the LL were smaller than during NW. Except for joint force, which was directed toward the anterior of the tibia, knee joint forces in the TL were smaller than during NW. When descending, maximum flexion angles of the three joints of the LL were smaller than during NW. The quadriceps tension and the soleus tension in the LL were smaller than during NW. Knee joint forces in the LL were smaller than during NW. The results suggested that 1) When ascending, if a patient has a failure in the system of knee extension, the unaffected side should be made the LL and the affected side the TL. Also, if there is a failure in the system of plantar flexion, the unaffected side should be the TL and the affected side the LL. 2) When descending, if there is a failure in one limb, the unaffected side should be the TL and the affected side the LL.