某电子加工企业手工提举作业的工效学评价

提举作业工人下背痛发生与作业中接触不良工效学因素密切相关。本文以某电子加工企业中手工提举工种及其作业活动为研究对象,采用根据我国人群生理特征等调整的NIOSH修正提举方程计算其提举指数,实现对不良工效学负荷的定量评价,对存在风险的岗位采取针对性的工效学改善措施,有效地预防肌肉骨骼疾患。     

民航手工搬举作业人员下背痛现状与预防

<正>随着现代工业技术的迅速发展,很多行业生产工艺已基本实现机械化、自动化。而在许多服务领域和制造业中手工提举却仍然普遍存在,与手工搬运提举有关的肌肉骨骼疾患(MSDs),特别是下背痛(LBP)发病逐渐增多[1,2],已引起企业及国内职业卫生领域的关注。民航手工搬举作业包括沉重货物或行李的提举、移动、分拣、运载和装卸等操作,广泛存在重负荷、推拉、搬举、频繁重复性弯腰、屈膝、扭转等不良姿势和负荷作业中,是导致作业人员工作相关肌肉骨骼疾患(WMSDs)的重要因     

美国国立职业安全卫生研究所提举公式评价方法的研究进展

手工搬运(manual materials handling,MMH)包括提举(lifting)、放(lowering)、推(pushing)、拉(pulling)、运(carrying)等作业.1997年,美国国立职业安全卫生研究所(NIOSH)对肌肉骨骼疾患的工作场所危险因素进行系统归纳,认为下背痛(LBP)与MMH有强的相关性,特别是在提举作业中更是如此[1].     

手工搬运作业人体工效学评价方法实例应用

目的探讨建立手工搬运作业工效学评价方法,并在建设项目职业病危害评价工作中应用。方法选择某半导体企业锂电池生产车间87名存在手工提举作业的工人为接触组,采用调查问卷、统计分析、NIOSH提举指数等评价方法,对手工提举作业的不良工效学负荷进行人体工效学评价。结果该企业为电子加工行业,存在明显的不良工作姿势和手工提举任务的特点;经统计学处理分析,该公司车间作业工人肌肉骨骼损伤的发生率与对照组的差别尚无统计学意义(P0.05),分析不相关的原因主要为本次评价作业工人年龄偏小、工龄短等因素影响;根据我国人体数据修正过的NIOSH提举指数对搬举作业人体工效学进行定量评价,说明现有作业环境存在诱发作业者搬举疲劳的风险因素,但未达到肌肉骨骼疾患发生风险明显增加的程度。结论长期手工提举等作业可能导致与此有关的肌肉骨骼疾患,但我国尚未将职业性腰背痛列入职业病名单,也未制定手工提举指南和重量限值,今后应在建设项目职业病危害评价工作中开展手工提升或搬运作业工效学评价,加强生产环节的职业病危害防护,防止发生职业危害。     

静态肌力及其影响因素的探讨

目的了解不同人群的部分人体测量学参数及其静态肌力,探讨静态肌力的影响因素。方法选择193名工人、行政人员和大学生作为研究对象,其中男146例、女47例;测量其手握力、臂提举力、肩提举力和腰拉力。结果静态肌力测试结果表明,男性平均左手握力、右手握力、臂提举力、肩提举力和腰拉力分别为(42.07±7.20)、(43.92±7.14)、(26.79±4.64)、(33.79±6.88)、(88.56±17.98)kg,而女性则分别为(21.29±5.09)、(23.26±5.47)、(13.29±3.37)、(18.52±4.01)、(41.06±12.04)kg;女性各种肌力均小于男性,约为男性的50%。年龄比较可见,各种肌力以40~岁组较高。性别和体重与静态肌力存在明显相关。以体重为校正参数,可见各组握力的差异无统计学意义(P<0.05),仅男性工人腰拉力>大学生>行政人员,年龄间比较见相对肌力除腰拉力各年龄组有所不同外,其他肌力各年龄组相似。结论以体重为自变量,可建立肌力预测方程。相对肌力的计算可消除体重等肌力的干扰。     

金属加工作业的工效学负荷与肌肉骨骼疾患的关系

目的　了解金属加工行业的肌肉骨骼疾患情况 ,分析其危险因素 ,初步探讨提举系数(LI)在中国应用的有效性和实用性。方法　选择 6 9名从事手工操作的金属加工工人作为提举作业组 (JobA) ,另选同一企业机械化程度较高的 5 1名工人作为对照组 (JobB)。采用问卷调查、Ovako劳动姿势分析系统 (OvakoWorkingPostureAnalysingSystem ,OWAS)、提举参数测量及日提举负荷量计算等方法分析负荷与下背痛的关系。结果　JobA组的下背痛患病率明显高于JobB组 ,在过去 12个月内 ,下背痛持续 2 4h以上的分别为 6 3.77%、37.2 5 % ,持续 1周以上的分别为 2 6 .0 9%、5 .88% ;JobA组的背部姿势异常率 (6 6 % )高于JobB组 (6 3% ) ,差异有显著性 (P <0 .0 5 )。JobA的提举指数为 2 .4 ,高于 1.0的限值 (JobB为 0

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煤矿工人肌肉骨骼损伤与社会心理因素关系的研究

目的 探讨社会心理因素与肌肉骨骼损伤的关系,为制定预防肌肉骨骼损伤的措施和策略提供科学依据.方法 对某煤矿集团一矿区的500名工人进行肌肉骨骼损伤的现况调查,应用北欧肌肉骨骼损伤标准问卷调查评估煤矿工人肌肉骨骼损伤;采用Logistic回归分析法分析社会心理因素对肌肉骨骼损伤的影响.结果 在过去的1年中,有227名煤矿工人自诉患有肌肉骨骼损伤,占总人数的60.9％,下背痛最为严重.高工工作要求(OR=1.3,95％CI:1.3～3.5)、低工作控制(OR=1.6,95％CI:1.0～2.4)、低人际关系( OR=1.9,95％CI:1.2～3.0)和低工作满意度(OR=1.6,95％CI:1.0～2.4)是肌肉骨骼损伤发生的危险因素.结论 社会心理因素对肌肉骨骼损伤的发生有影响,提示在制定预防肌肉骨骼损伤措施时需考虑社会心理因素.     

木工推台锯岗位手工搬举作业腰部受力生物力学分析

目的 评估木工推台锯岗位手工搬举作业中是否存在导致职业性下背痛和职业性肌肉骨骼疾患(WMSD)发生的职业性风险,并进一步提出预防与降低WMSD风险的合理工作方式和干预措施.方法 应用美国职业安全卫生研究院(NIOSH)抬举方程,分析木工推台锯岗位中常见的抬举作业任务,并建立该搬运作业的腰椎生物力学模型,计算该作业典型姿势下腰椎间盘(L5/S1)的负荷.结果 随着抬举作业起始面高度的变化,提举重量推荐值(RWL)随之变化,并且呈现出类抛物线的变化规律,最低值为9.05 kg;在搬运作业中,作用在L5/S1上的外力合力为3579 N;其中,挤压力为3570 N,略大于NIOSH提出的年轻健康工人耐受限值3400 N.家具制造木工推台锯岗位MMH作业人员腰椎受伤的可能性较大.结论 木工推台锯岗位手工搬举作业时,存在导致职业性下背痛和WMSD发生的职业性风险;为避免职业性损伤的发生,该岗位的手工搬举作业的任务宜进行优化设计.     

手工提举的竖脊肌力-电分析

目的评估提举作业的竖脊肌负荷和疲劳效应，分析其力-电关系。方法在某机械加工企业，分别选择两不同工种（Job）的工人，即6名以手工提举为主的Job A铣工，提举指数为2．1～2．2和4名以机械提举为主的Job B的铣工，提举指数〈1。结果Job A典型提举时左右竖脊肌的平均负荷分别为最大随意收缩（MVC）的表面肌电活动的47．61％和39．3％，一般状态则分别为MVC的表面肌电活动的15．57％和15．64％，而Job B的左右竖脊肌平均负荷仅为MVC的表面肌电活动的8．76％和8．04％。Job A的腰拉力和MVC均随工作时间的延长而呈下降趋势，而Job B的工人则基本稳定。以竖脊肌最大收缩（腰拉力）、肌电活动作相关分析，腰拉力与左、右竖脊肌肌电活动的相关系数分别为0．474、0．597（P〈0．01）。而左右两侧竖脊肌相关系数为0．727（P〈0．01）。结论表面肌电图可以客观反映提举活动的负荷，也提示提举致肌肉疲劳的征象。表面肌电图可为手工提举的负荷评价提供一种重要的、客观的评价方法。     

机场搬运作业人员下背痛工效学因素分析

目的调查某机场行李货物搬运作业人员肌肉骨骼疾患患病情况,探讨影响机场搬运作业人员下背痛(LBP)的工效学因素。方法选取某机场在职行李货物搬运作业人员383人为研究对象,采用自主研发的《肌肉骨骼损伤问卷》调查损伤情况,职业紧张调查参考工作内容量表(JCQ)中的部分内容,采取横断面调查,对可能影响作业人员下背痛的不同因素进行单因素χ2检验和多因素Logistic回归分析。结果机场行李货物搬运作业人员下背痛的总患病率为62.7%。按α=0.05水平,Logistic回归分析结果显示影响机场行李货物搬运作业人员下背痛患病风险的6个因素均有统计学意义,其中5个危险因素:背部弯曲幅度、经常转身、弯腰同时转身、劳动强度和吸烟;1个保护因素:经常锻炼身体。结论不良工作姿势、劳动强度和不良生活习惯对下背痛的患病均有不同程度的影响。减少吸烟行为,增加体育锻炼次数,能够降低搬运作业人员下背痛发病的风险。     

EMG Biofeedback as a Tool for Simulating the Effects of Specific Leg Muscle Weakness on a Lifting Task

This study investigated the use of EMG biofeedback to simulate weakened rectus femorii and gastrocnemii muscles during the performance of a lifting task. Eight healthy women performed 15 kg free-style lifts from floor level. Three conditions were tested: unconstrained lifting, lifting with rectus femorii activity volitionally limited bilaterally through EMG biofeedback to less than 45% of maximal EMG activity, and lifting with the gastrocnemii limited to a similar level. Limiting leg muscle activity through biofeedback led to an alteration of lifting strategy, with resulting performance variables (joint angles and torques, angular velocities, center of pressure excursion, and segment coordination) comparing favorably with those from lifting trials performed by six women with moderate leg muscle weaknesses. The data indicate that EMG biofeedback can be used to simulate the effects of leg muscle weakness during these lifts, providing a new tool to study the biomechanics of muscle weakness.     

Stress fracture of the distal tibia and fibula through heavy lifting

BACKGROUND: Occupational stress fractures are reported among athletes, soldiers, ballet dancers, and in connection with shoveling. METHODS: A literature search on occupational stress fractures was performed. The biomechanical stress in association with special lifting tasks was estimated. RESULTS: A 59-year-old male welder presented with a stress fracture of the left distal tibia and fibula in connection with heavy lifting. The object was in front and lifted while he partly stood on one leg, which was rotated during the lifting. There was no considerable previous exposure to heavy lifting. CONCLUSION: It is likely, that this stress fracture was the result of strain on tibia and fibula through this composite lifting operation.     

The effect of complex dynamic lifting and lowering characteristics on trunk muscles recruitment

A better understanding of how the neuromuscular spinal system behaves during lifting and lowering could provide more insight about potential causes of occupational low back disorders (LBDs), and could help in the prevention and rehabilitation process of these disorders. The purpose of this study was to quantify trunk muscle activities under various whole-body free-dynamic symmetric and asymmetric complex lifting and lowering tasks. Eleven male subjects with no prior history of LBDs participated in the study. Electromyographic activities of ten trunk muscles were monitored while subjects either symmetrically or asymmetrically lifted and lowered a box under three different speeds and three weights. The results showed that all ten muscles were responsive to various experimental conditions with the erector spinae and internal oblique muscles showing the greatest response. Substantial electromyographic activities were observed in muscles that were on the contralateral side of the load. Lowering conditions yielded consistently lower muscular activities than their corresponding lifting conditions. These results show that it is essential to consider multiple trunk muscles in modeling efforts of quantifying spinal loading, as well as for back rehabilitation research purposes.     

The effect of lumbar support belts on isometric force production during a simulated lift

The use of back support belts by industrial workers has become common in recent years. The rationale for the use of these belts is based on the theory that they increase intra-abdominal pressure. Raised intra-abdominal pressure is believed to reduce compression forces on the spinal column and to assist the back extensor muscles in producing extension torque. The assistance of the belt is believed to protect the spine from injury. Thirty males and thirty females participated in this study which assessed the effect of two different back support belts (one synthetic and one leather) on isometric muscle-force production of individuals performing a static leg lift (SLL). A Latin Square double cross-over design was employed. Analysis of variance tests revealed that in males the use of the synthetic belt allowed for greater force production than a control trial, but no difference could be detected between the leather belt and either the synthetic belt or the control. In the female group, no difference in force production occurred across the three conditions. Implications and suggestions for further study are discussed.     

Effects of Transfer Distance on Spine Kinematics for De-palletizing Tasks

One approach to reducing lateral bending and twisting in manual lifting tasks is to separate the lift's origin and destination, thereby encouraging lifters to step and turn their entire bodies. The objective of the current study was to determine how the degree to which one laterally bends and twists changes with transfer distance and initial lift height. Eighteen males lifted 10.9 kg boxes from a conveyor 0.5 m, 0.9 m, and 1.3 m above the floor and placed the boxes on a conveyor .50, .75, 1.00, 1.25, 1.50, or 1.75 m away at a height of .9 m. During picking, lateral bending and trunk extension velocities increased with increasing transfer distances. When placing the box, the degree of twisting decreased with increased transfer distance. In sum, when attempting to control the twisting and lateral bending during de-palletizing, the lift origin and destination should be separated by between 1 and 1.25 meters.     

Reliability of Lift Alert™ as a feedback device for detecting changes in body position

The Lift Alert is a small battery-operated unit, usually worn on the back of a worker's collar that is designed to provide a form of biofeedback about changes in trunk position during lifting tasks. The purpose of this study was to determine how consistent the Lift Alert was at each of five different sensitivity settings (A-E) in detecting changes in trunk flexion in a given individual during a controlled bending maneuver. The subjects were videotaped while performing a series of trials of bending maneuvers at each of the sensitivity settings according to a specific protocol. The videotapes were then converted onto a computer program where the still images were captured and marked for data analysis. The reliability of the Lift Alert was determined by calculating a coefficient of agreement, that is, the percentage of trials that were within both 10 and 15 degrees for each of the trials at a given setting for a single individual. The coefficient of agreement for all trials at all five settings was 0.76 within 10 degrees and 0.92 within 15 degrees. The results of this study suggest that the Lift Alert is a reliable device for detecting changes in trunk flexion during a controlled bending maneuver for a given individual.     

Physically strenuous work during pregnancy and risk of preterm birth

The aim of the study was to examine the risk of preterm birth following physically strenuous work during pregnancy. We included 343 pregnant women referred to an occupational medical clinic. Data on preterm birth and covariates were retrieved from the Danish Birth Registry. Risk estimates were computed by logistic regression using a population sample of gainfully employed women as reference (n = 345,915). The risk of preterm birth was increased in women lifting heavy loads during pregnancy (OR 1.40, 95% CI [0.88, 2.23]) but not in women with physically strenuous work (OR 0.98, 95% CI [0.66, 1.46]). The mean gestational age in the heavy-lifting group compared to the reference group was 2.4 days shorter (95% CI [0.36, 4.41]). The study challenges earlier reassuring findings as heavy-lifting pregnant women had a reduced gestational age, indicating a possibility of increased risk of preterm birth.     

The Effects of a Four-Week Muscle Strengthening Program on Maximum Acceptable Lifting Load

The purpose of this study is to investigate the effects of a traditional strengthening program on subjects' maximum acceptable lifting load. Nineteen (nine males, ten females) university students volunteered for the present study. They were randomly divided into a training group (five males, seven females) and a control group (four males, three females). The training group participated in 12 sessions of alternate day traditional dead weight strengthening programs for a period of 4 weeks. The measurements of the training effects included assessment of the maximum acceptable lifting load by psychophysical approach and isokinetic peak torque of the back extensors, knee extensors, shoulder abductors, and elbow flexors. Multivariate ANOVA was used to test for the training effect. Results revealed significant improvement in the maximum acceptable lifting load (p < 0.001) and back extensors peak torque (p = 0.039) after 4 weeks of training. It is concluded that a 4-week free weight muscle training program is effective in improving an individual's maximum acceptable lifting load. This type of physical training program may be useful to people engaged in manual material handling tasks.     

The effect of obesity on postural stability during a standardized lifting task

The objective of this study was to assess the effect of obesity on postural stability during a standardized lifting task. Twelve young males, six obese and six non-obese, completed three replications of repeated six lifts (at a rate of six lifts per minutes) at two levels of loads (10% and 25% of capacity) crossed with two levels of orientation (0° and 45° from sagittal plane). Postural stability measures showed that center of pressure sway path and sway area were ～21% and ～53% lower with obesity, respectively. Additionally, frequency band of amplitude spectrum in the medial lateral direction at 0° lifting orientation was significantly lower with obesity. The results suggest that obesity, as measured by body mass index, does not impair balance control in healthy young males when lifting load is relative to the capacity.     

The effect of ergonomic interventions in healthcare facilities on musculoskeletal disorders

BACKGROUND: The high incidence of musculoskeletal disorders (MSDs) among healthcare workers suggests that the introduction of ergonomic interventions could be beneficial. While laboratory studies have clearly documented the efficacy of ergonomic devices, few studies have examined their effectiveness in the healthcare workplace. METHODS: This study evaluated a statewide program that provided ergonomic consultation and financial support for purchasing ergonomic devices, which aid in patient handling and lifting. Changes in MSD rates between baseline (1 year pre-intervention) and post-intervention (up to 2 years) periods were examined in 100 work units in 86 healthcare facilities. RESULTS: The median MSD rate decreased from 12.32 to 6.64 per 200,000 employee-hours, a decrease greater than the secular trend for the study period (1999-2003). CONCLUSIONS: This study suggests that ergonomic consultation and financial support for purchasing ergonomic equipment can be an effective intervention to reduce MSDs among healthcare workers.