Abstract
For ascending and descending steps with a Lofstrand crutch it is recommended to raise the sound limb first during ascending and to lower the affected limb first during descending, which we called ‘the ordinary order’. We called the reverse motion, such as to raise the affected limb first during ascending and to lower the sound limb first during descending, ‘the inverse order’. The purpose of this study was to compare the movements in these two orders with a motion analysis technique. The joint moments of the upper and the lower extremities were measured and compared.
Ten healthy adults participated in this study. One leg of each subject was assumed to be an affected limb, They were told not to load more than two third of their body weight on the affected limb during the movement, which was checked with a load sensor worn by the subject. In this condition they ascended and descended steps using a Lofstrand crutch in ‘the ordinary order’ and ‘the inverse order’. The movement was measured with a 3D motion analysis system (VICON512) and force plates (AMTI). The joint moment of the upper and the lower extremities were calculated using a link segment model. The joint moment during the isometric maximum voluntary contraction (MVC) was also measured for each joint of the subjects. The peak value of the joint moment during movement was normalized by the MVC value to obtain the relative load for each joint.
As a result, the peak joint moment of the knee joint during ‘the ordinary order’ and the shoulder joint during ‘the inverse order’ showed large values. The elbow joint moment showed a small value and there was no significant difference between the two orders. However, the normalized value of the shoulder joint moment during movement in ‘the inverse order’ showed a significantly large value, 75% for ascending and 90% for descending. The result showed that the physical load in ‘the ordinary order’ was small, which was confirmed by the kinetic analysis.
