Yates J W, Karwowski W
Exercise Physiology Laboratory, University of Louisville, KY 40292.
Ergonomics. 1992 Jul-Aug;35(7-8):889-98. doi: 10.1080/00140139208967369.
The objective of this project was to compare the muscular effort exerted during manual lifting tasks performed in standing versus seated posture. Six male undergraduate and graduate students performed 12 different static and dynamic lifts in both sitting and standing positions. During each effort electromyographic (EMG) data were collected on four muscles groups (low back, upper back, shoulder, and abdominals). Four contractions were designed to elicit maximum muscular effort in the four groups being monitored. The remaining data were then expressed as a percentage of maximum EMG. Each subject performed the following: maximum static lift when sitting; maximum static lift when standing; sitting, static lift with 15.9 kg; standing, static lift with 15.9 kg; dynamic sit-forward lift with 15.9 kg, dynamic stand-forward lift with 15.9 kg, dynamic sit-twist with 15.9 kg, dynamic stand-vertical lift with 15.9 kg. Each of the lifts was performed with a wooden tray with slotted handles. Root mean square (RMS) values of the EMG data were calculated for three second periods. EMG activity in the low back, upper back, and shoulder was greater during sitting lifting than during standing lifting. The sit-twist lift resulted in the highest EMG in the abdominal muscles. Dynamic lifts resulted in more muscle activity than did static lifts. From these data it was concluded that sitting-lifting results in greater stress in the low back, upper back, and shoulders than does lifting while standing.
该项目的目的是比较在站立姿势与坐姿下进行手动提举任务时所施加的肌肉力量。六名男性本科生和研究生在坐姿和站姿下分别进行了12种不同的静态和动态提举动作。在每次用力过程中，采集了四组肌肉（下背部、上背部、肩部和腹部）的肌电图（EMG）数据。设计了四种收缩动作，以在被监测的四组肌肉中引发最大肌肉力量。其余数据则表示为最大肌电图的百分比。每位受试者进行了以下动作：坐姿下的最大静态提举；站姿下的最大静态提举；坐姿下提举15.9千克的静态提举；站姿下提举15.9千克的静态提举；提举15.9千克的动态坐姿前屈提举、提举15.9千克的动态站姿前屈提举、提举15.9千克的动态坐姿扭转提举、提举15.9千克的动态站姿垂直提举。每次提举都使用带有开槽手柄的木托盘进行。对肌电图数据的均方根（RMS）值进行了三秒时间段内的计算。坐姿提举时，下背部、上背部和肩部的肌电图活动比站姿提举时更大。坐姿扭转提举导致腹部肌肉的肌电图值最高。动态提举比静态提举导致更多的肌肉活动。从这些数据得出的结论是，与站立提举相比，坐姿提举会在下背部、上背部和肩部产生更大的压力。
