Hyun Seung-Hyun, Ryew Che-Cheong
Department of Kinesiology, College of Natural Science, Jeju National University, Jeju, Korea.
J Exerc Rehabil. 2017 Dec 27;13(6):722-727. doi: 10.12965/jer.1735092.546. eCollection 2017 Dec.
The aim of this study is to compare and analyze the components of ground reaction force (GRF) relative to the foothold heights during downward step of 16-t truck. Adult males (n= 10) jumped downward from each 1st, 2nd, 3rd foothold step and driver's seat orderly using hand rail. Sampling rate of force components of 3 axis (medial-lateral [ML] GRF, anterior-posterior [AP] GRF, peak vertical force [PVF]), variables (COPx, COPy, COP area) of center of pressure (COP), loading rate, and stability index (ML, AP, vertical, and dynamic postural stability index [DPSI]) processed from GRF system was cut off at 1,000 Hz. and variables was processed with repeated one-way analysis of variance. AP GRF, PVF and loading rate showed higher value in case of not used hand rail than that used hand rail in all 1st, 2nd, and 3rd of foothold step. DPSI showed more lowered stability in order of 2nd, 3rd step than 1st foothold step used with hand rail, of which showed lowest stability from driver's seat. COPx, COPy, and COP area showed higher value in case of 2nd and 3rd than that of 1st of foothold step, and showed lowest stability from driver's seat. It is more desirable for cargo truck driver to utilize an available hand rail in order of 3rd, 2nd, and 1st of foothold step than downward stepping directly, thus by which may results in decrease of falling injuries and minimization of impulsive force transferring to muscular-skeletal system.
本研究的目的是比较和分析16吨卡车下行过程中与立足点高度相关的地面反作用力（GRF）的组成部分。成年男性（n = 10）使用扶手，从第1、第2、第3个立足点台阶和驾驶座依次向下跳跃。从GRF系统处理得到的3轴力分量（内侧-外侧[ML] GRF、前后[AP] GRF、峰值垂直力[PVF]）、压力中心（COP）的变量（COPx、COPy、COP面积）、加载率和稳定性指数（ML、AP、垂直和动态姿势稳定性指数[DPSI]）的采样率被截断为1000 Hz。变量采用重复单因素方差分析进行处理。在所有第1、第2和第3个立足点台阶中，未使用扶手时的AP GRF、PVF和加载率均高于使用扶手时的值。在使用扶手的情况下，DPSI显示从第2、第3步到第1个立足点台阶的稳定性依次降低，其中从驾驶座向下时稳定性最低。COPx、COPy和COP面积在第2和第3个立足点台阶时的值高于第1个台阶，并且从驾驶座向下时稳定性最低。对于货运卡车司机来说，按照第3、第2和第1个立足点台阶的顺序使用可用扶手比直接向下迈步更可取，这样可能会减少跌倒伤害，并使传递到肌肉骨骼系统的冲击力最小化。
