手工搬举作业的最大可接受搬举重量

目的对手工搬举作业的最大可接受搬举重量（MAWL）进行研究,为我国制订手工搬举作业劳动负荷的标准提供依据.方法 用心理物理学方法对13名男性和10名女性受试者的MAWL进行了研究,并与推荐搬举重量限值进行比较.结果 男女受试者的MAWL均随着搬举高度的上升逐渐降低.当搬举高度超过肩关节时,MAWL急剧下降.男性受试者在水平距离25 cm处,其推荐搬举重量均大于MAWL,但在水平距离45、63cm处,推荐值均小于MAWL.男性受试者的平均MAWL比女性受试者高30.8%.在同一高度,随着水平距离的增加,MAWL逐渐下降,男女受试者结果一致.男性受试者不对称搬举时,扭转的角度越大,MAWL越低.扭转角度和搬举能力呈负相关（r=-0.996 6,P＜0.01）.不同扭转角度的推荐搬举重量限值均比MAWL低,且差异有统计学意义（P＜0.01）.结论 美国国家职业安全卫生研究所（NIOSH）搬举方程对于水平距离和不对称的校正是充分的,但对于高度的校正是不足的,尤其是对于过肩的搬举作业是不适合的,对于过肩搬举作业的推荐搬举重量限值还应降低.NIOSH搬举方程应考虑性别因素的影响,可加入性别常数项S;如果性别为男性,则S=1;如果性别为女性,则S=0.692.

Maximum acceptable weight of lift for manual lifting tasks

OBJECTIVE: To explore the maximum acceptable weight of lift (MAWL) in different lifting conditions and the suitable lifting equation for the stipulation of occupational health standard of manual lifting tasks in China. METHODS: The MAWL was investigated among the thirteen male and ten female students using psychophysical methodology and the recommended weight of limit (RWL) was compared. RESULTS: The MAWL of male and female subjects was decreased gradually with the increase of lifting height. Once the height of lifting was over shoulder, the MAWL was decreased dramatically. The RWL was greater than the MAWL at 25 cm horizontal distance in male subjects, but the RWL was smaller than the MAWL at the distance of 45 cm and 63 cm. The average MAWL of male subjects was 30.8% greater than that of female subjects. The MAWL was decreased gradually with increase of the horizontal distance at the same height of lifting. The result of the male subjects was consistent with that of the female subjects. For the asymmetric lifting tasks of the male subjects, the bigger the angle of rotation was, the less the MAWL became. The angle of rotation had negative correlation with the capability of lifting (r = -0.996 6, P < 0.01). When the subjects performed asymmetric lifting tasks, the RWL was smaller than the MAWL and the difference was significant. CONCLUSION: The revision is sufficient for the horizontal distance and asymmetric lifting in the NIOSH lifting equation, but it is not suitable for height, especially for the task of lifting over shoulder. The RWL for the task of lifting over shoulder should be lowered. The factor of gender should be taken into account in the lifting equation and the constant of gender S can be added. Then S = 1 for male while S = 0.692 for female.