Background Shoemaking industry workers are prone to work-related musculoskeletal disorders (WMSDs) due to long-term awkward postures during the work process. There is little research on the prevalence and influencing factors of WMSDs in the knee region of this industry, and it should be taken seriously. Objective To estimate the prevalence of work-related knee pain among shoemaking workers and analyze the related influencing factors. Methods A total of 6982 shoemaking workers were selected from 26 shoemaking factories in Guangdong, Hubei, Fujian, Chongqing, Shandong, Zhejiang, and Jingxi by convenience sampling. Prevalence of work-related knee pain in past year, demographic characteristics, occupational related factors, and work posture were collected by a cross-sectional survey using the electronic version of Musculoskeletal Disorder Questionnaire. Logistic regression analysis was used to analyze the influencing factors that may lead to work-related knee pain. Results This survey collected 6982 valid questionnaires with a recovery rate of 98.3%. The prevalence of work-related knee pain of shoemaking workers in the past 12 months was 13.0% (908/6982). According to the results of logistic regression analysis, compared with workers with less than 5 years of service, workers with 5-10 years of service (OR=1.21, 95%CI: 1.02, 1.45) and more than 10 years (1.53, 95%CI: 1.27, 1.83) showed a higher risk of knee WMSDs; sometimes, often and very frequent (reference : rarely or never) long-term standing (OR=1.33, 95%CI: 1.08, 1.64; OR=2.67, 95%CI: 2.10, 3.39; OR=2.75, 95%CI: 2.08, 3.63) and sometimes, often and very frequent (reference: rarely or never) long-term squatting or kneeling (OR=1.80, 95%CI: 1.47, 2.21; OR=2.43, 95%CI: 1.58, 3.75; OR=3.22, 95%CI: 1.66, 6.24) increased the risk of knee pain: long-term bending (OR=1.59, 95%CI: 1.34, 1.89) and often repeated movement of lower limbs and ankles (OR=1.48, 95%CI: 1.25, 1.75) were also risk factors for knee WMSDs among shoemaking industry workers (P<0.05). Adequate rest time (OR=0.58, 95%CI: 0.49, 0.68) and able to stretch or change leg posture (OR=0.75, 95%CI: 0.64, 0.88) reduced the risk of knee WMSDs (P<0.05). Conclusion In the shoemaking industry, length of service and awkward postures are risk factors for knee pain. The shoemaking enterprises should ensure that workers have sufficient rest time, reduce long-term standing, squatting, kneeling, and bending postures, as well as lower limbs repetition in order to reduce the occurrence of knee WMSDs of workers.

{L-End}Objective To analyze the local muscle response under continuous ergonomic workload by simulating manual lifting, and to screen the sensitive metabolic biomarkers during fatigue process. {L-End}Methods A total of 13 healthy male volunteers were selected as the study subjects using simple random sampling method. Study subjects underwent repetitive simulated manual lifting for four periods (T1 to T4), each lasting 12 minutes. The degree of work-related fatigue in the forearm, upper arm, shoulder, back, and leg muscles, and the whole body was accessed using Borg 6-20 Rating of Perceived Exertion (RPE) Scale. The venous blood samples were collected from elbow between each two periods to detect the levels of eight metabolic biomarkers: ammonia, lactate, creatine kinase, lactate dehydrogenase (LDH), C-terminal telopeptide of type Ⅰ collagen (CTX-Ⅰ), C-terminal telopeptide of type Ⅱ collagen (CTX-Ⅱ), cartilage oligomeric matrix protein (COMP), and calcium ions. {L-End}Results The RPE scores of the study subjects for the muscles of five body parts and the whole body increased with the increasing lifting periods (all P<0.01). Fatigue was observed in all target muscles, with overall body fatigue occurring in the T2 period. The levels of ammonia, lactate, creatine kinase, LDH, COMP, and calcium ions in the serum of study subjects were higher in the T1 to T4 periods than in the T0 period (all P<0.05). The serum CTX-Ⅰ level was higher in the T1 and T3 periods than that in the T0 period (all P<0.05) , and the serum CTX-Ⅱ level was higher in the T1, T2 and T4 periods than that in the T0 period (all P<0.05). The level of these eight serum metabolic biomarkers fluctuated during the T1 to T4 periods. The serum creatine kinase level increased with the period of lifting (all P<0.05). The serum lactate level was higher in the T3 period than those in the T1 and T2 periods (all P<0.05). The serum LDH and calcium ion levels were higher in the T2 to T4 periods than that in the T1 period (all P<0.05). The serum COMP level was higher in the T2 and T3 periods than that in the T1 period (all P<0.05). Except for CTX-Ⅰ, the levels of other seven metabolic markers in serum were higher in individuals after fatigue than before fatigue (all P<0.05). {L-End}Conclusion Serum metabolic biomarkers such as ammonia, lactate, creatine kinase, calcium ions, LDH, CTX-Ⅱ, and COMP exhibit significant changes before and after fatigue. These metabolic biomarkers could be used as sensitive biomarkers for evaluating muscle fatigue during repetitive works.

{L-End}Objective To investigate the current status and influencing factors of leg work-related musculoskeletal disorders (WMSDs) in shipbuilding workers. {L-End}Methods A total of 3 393 shipbuilding workers from Guangdong Province, Liaoning Province, Shandong Province, and Beijing City were selected as the research subjects using the convenience sampling method. The Chinese Version of the Musculoskeletal Disorders Questionnaire was used to investigate the prevalence of leg WMSDs in the past year. A multivariate logistic regression model was used to analyze the influencing factors of leg WMSDs. {L-End}Results The prevalence of leg WMSDs in the research subjects was 11.3% (382/3 393). The result of multivariate logistic regression showed that the risk of leg WMSDs was higher in workers with a length of service >10 years than those with a length of service <5 years (P<0.05). Workers with frequent used of vibration tools at work had higher the risk of leg WMSDs (all P<0.05). Workers who did the same work every day, had insufficient rest time, had a shortage of department staff, and those who often repeated the same leg movements had a higher risk of leg WMSDs (all P<0.05). The risk of leg WMSDs in workers who sometimes stand for a long time was lower than that in workers who rarely stand for a long time (P<0.01). {L-End}Conclusion Length of service, rarely long-standing work, use of vibration tools at work, daily engagement in the same work, in-adequate rest time, shortage of department staff, and frequent repetition of the same leg movements are all influencing factors for leg WMSDs in shipbuilding workers.

Background Furniture manufacturing is one of the typical labor-intensive industries, and workers in this industry face a high risk of work-related musculoskeletal disorders (WMSDs), which seriously affect the physical and mental health of workers. Objective To explore the prevalence and potential risk factors of WMSDs among workers in a large-scale furniture manufacturing factory. Methods A cross-sectional study of 3431 workers in a furniture factory in Guangdong Province was conducted from September to December 2019. Information including reported WMSDs in various body parts in the past year, demographic characteristics, work organization factors, job characteristics, and work postures was collected by an electronic version of Musculoskeletal Disorders Questionnaire. Pearson χ² test and binary logistic regression were used to analyze the risk factors leading to WMSDs. Results The overall prevalence rate of WMSDs was 32.12% (1102/3431). The most common WMSDs symptoms occurred in the neck (16.85%), followed by the feet (15.27%), shoulders (14.81%), and hands (14.25%). The prevalence rates of WMSDs in the neck, shoulders, elbows, hands, legs, and feet were significantly different among different types of work (P<0.05). The results of multiple logistic regression analysis showed that individual factors, work organization factors, job characteristics, and awkward work postures were associated with the frequency of reporting WMSDs in specific parts of workers. Comparatively poor physical health (including moderate, poor, and very poor) was positively correlated with neck, shoulder, hand, and foot WMSDs (OR=1.479-4.077); working with an uncomfortable posture (OR=1.983) and doing the same task almost every day (OR=1.783) were positively correlated with neck pain; doing the same task almost every day (OR=2.408) and neck twisting for a long time (OR=1.830) were positively correlated with shoulder pain; bending wrists up and down frequently (OR=1.948) and bending wrists for a long time (OR=2.081) were positively correlated with hand pain; prolonged standing (OR=1.953) and often working overtime (OR=1.627) were positively correlated with feet pain; sufficient rest time was negatively correlated with WMSDs in the neck, shoulders, hands, and foot (OR=0.544-0.717). Conclusion The prevalence rate of WMSDs in furniture manufacturing workers is relatively high, and neck, feet, shoulders, and hands are the most involved body parts. The frequency of reporting WMSDs is related to individual factors, work organization factors, job characteristics, and awkward work postures.

Objective:To investigate the occurrence of work-related musculoskeletal disorders (WMSDs) in logistics workers of automobile manufacturing enterprises in Guangzhou, and explore their potential categories and influencing factors, so as to provide basis for the prevention and control of WMSDs in logistics workers of automobile manufacturing enterprises.Methods:From April to May 2020, a convenient sampling method was adopted to select 1442 logistics workers in 2 automobile manufacturing enterprises in Guangzhou as the research objects. The incidence of WMSDs among them was investigated by using the Nordic Musculoskeletal Disorders Questionnaire, and the incidence pattern of WMSDs among the subjects was analyzed by the method of potential category analysis. Chi-square test and multiple logistic regression model were used to analyze the influencing factors of the disease.Results:The total prevalence of WMSDs was 42.9% (619/1442). The three parts with high prevalence of WMSDs were neck (23.5%, 339/1442), shoulder (21.3%, 307/1442) and lower back (19.1%, 275/1442). 69.0% (427/619) of the patients showed simultaneous disease in two or more sites. The subjects were divided into four latent groups by the analysis of latent categories: the group with multiple body parts (4.51%), the group with very low or no disease (70.39%), the group with shoulder and neck and upper back (11.37%), and the group with limbs and lower back (13.73%). Multivariate logistic regression showed that compared with the "very low or no disease group", the risk factors of multiple body parts of automotive logistics workers suffering from WMSDs mainly included: Working posture uncomfortable ( OR=3.10, 95% CI: 1.44~6.70, P=0.004), often bend and turn ( OR=2.36, 95% CI: 1.05~5.29, P=0.037), bend your knees homework for a long time ( OR=2.29, 95% CI: 1.17~4.47, P=0.015) ; Working posture uncomfortable ( OR=2.26, 95% CI: 1.51~3.38, P<0.001), bending the neck ( OR=1.68, 95% CI: 1.03~2.74, P=0.036), neck minister time keep the same position ( OR=1.81, 95% CI: 1.22~2.67, P= 0.003) It is a risk factor for shoulder, neck and upper back WMSDs; Risk factors for limb-lower back WMSDs include: Length > 10 years ( OR=2.16, 95% CI: 1.24~3.78, P<0.001), the working position uncomfortable ( OR=2.38, 95% CI: 1.63~3.48, P<0.001), bending the neck ( OR=1.66, 95% CI: 1.03~2.68, P=0.039) . Conclusion:The prevalence rate of WMSDs among logistics workers in automobile manufacturing enterprises is high, which has obvious characteristics of classification and comorbis, and is closely related to individual characteristics such as sufficient rest time and working posture of workers.

Objective:To investigate the occurrence of work-related musculoskeletal disorders (WMSDs) in logistics workers of automobile manufacturing enterprises in Guangzhou, and explore their potential categories and influencing factors, so as to provide basis for the prevention and control of WMSDs in logistics workers of automobile manufacturing enterprises.Methods:From April to May 2020, a convenient sampling method was adopted to select 1442 logistics workers in 2 automobile manufacturing enterprises in Guangzhou as the research objects. The incidence of WMSDs among them was investigated by using the Nordic Musculoskeletal Disorders Questionnaire, and the incidence pattern of WMSDs among the subjects was analyzed by the method of potential category analysis. Chi-square test and multiple logistic regression model were used to analyze the influencing factors of the disease.Results:The total prevalence of WMSDs was 42.9% (619/1442). The three parts with high prevalence of WMSDs were neck (23.5%, 339/1442), shoulder (21.3%, 307/1442) and lower back (19.1%, 275/1442). 69.0% (427/619) of the patients showed simultaneous disease in two or more sites. The subjects were divided into four latent groups by the analysis of latent categories: the group with multiple body parts (4.51%), the group with very low or no disease (70.39%), the group with shoulder and neck and upper back (11.37%), and the group with limbs and lower back (13.73%). Multivariate logistic regression showed that compared with the "very low or no disease group", the risk factors of multiple body parts of automotive logistics workers suffering from WMSDs mainly included: Working posture uncomfortable ( OR=3.10, 95% CI: 1.44~6.70, P=0.004), often bend and turn ( OR=2.36, 95% CI: 1.05~5.29, P=0.037), bend your knees homework for a long time ( OR=2.29, 95% CI: 1.17~4.47, P=0.015) ; Working posture uncomfortable ( OR=2.26, 95% CI: 1.51~3.38, P<0.001), bending the neck ( OR=1.68, 95% CI: 1.03~2.74, P=0.036), neck minister time keep the same position ( OR=1.81, 95% CI: 1.22~2.67, P= 0.003) It is a risk factor for shoulder, neck and upper back WMSDs; Risk factors for limb-lower back WMSDs include: Length > 10 years ( OR=2.16, 95% CI: 1.24~3.78, P<0.001), the working position uncomfortable ( OR=2.38, 95% CI: 1.63~3.48, P<0.001), bending the neck ( OR=1.66, 95% CI: 1.03~2.68, P=0.039) . Conclusion:The prevalence rate of WMSDs among logistics workers in automobile manufacturing enterprises is high, which has obvious characteristics of classification and comorbis, and is closely related to individual characteristics such as sufficient rest time and working posture of workers.

Objective:To investigate the occurrence of work-related musculoskeletal disorders (WMSDs) in the cabinet factory workers, and explore the influencing factors of workers' WMSDs.Methods:A cross-sectional survey method was used to investigate the risk factors such as basic conditions, labox dnganiza, ergonomics load and occurrence of WMSDs of 821 workers in a cabinet factory of a furniture manufacturing company in Guangdong Province using the electronic version of the Musculoskeletal Injury Questionnaire from October to December 2019. χ 2 test and logistic regression were used to analyze the risk factors leading to WMSDs. Results:The incidence of WMSDs in cabinet production workers reached 51.5% (423/821) , and the top three incidences were shoulder (28.4%, 233/821) , neck (28.1%, 231/821) , and wrist (25.9%, 213/821) . The incidence of neck WMSDs was statistically significant among different types of work ( P<0.05) . Multiple repetitive operations per minute ( OR=1.70) , torso often maintaining the same posture ( OR=1.61) , turning heads for a long time ( OR=1.58) and frequent heavy lifting ( OR=1.44) were risk factors for the occurrence of shoulder WMSDs ( P<0.05) . Frequent maintenance of the same posture in the neck ( OR=1.91) , repeated operations per minute ( OR=1.87) , shortage of department staff ( OR=1.65) and turning head for a long time ( OR=1.48) were risk factors for the occurrence of neck WMSDs ( P<0.05) . Long-term bending of the wrist ( OR=2.25) , grasping objects tightly ( OR=2.13) , working hard on the upper limbs or hands ( OR=1.91) , shortage of department personnel ( OR=1.84) , repeated operations per minute ( OR=1.68) and the use of vibration tools ( OR=1.51) were risk factors for the occurrence of WMSDs in the wrist ( P<0.05) . Conclusion:The incidence of WMSDs in cabinet factory is relatively high, the occurrence of WMSDs in the shoulders, necks and wrists is more serious. Reasonable labor organization and reducing the load of poor ergonomics in the workplace, can reduce the occurrence of WMSDs in production workers.

Objective:To investigate the occurrence of work-related musculoskeletal disorders (WMSDs) in the cabinet factory workers, and explore the influencing factors of workers' WMSDs.Methods:A cross-sectional survey method was used to investigate the risk factors such as basic conditions, labox dnganiza, ergonomics load and occurrence of WMSDs of 821 workers in a cabinet factory of a furniture manufacturing company in Guangdong Province using the electronic version of the Musculoskeletal Injury Questionnaire from October to December 2019. χ 2 test and logistic regression were used to analyze the risk factors leading to WMSDs. Results:The incidence of WMSDs in cabinet production workers reached 51.5% (423/821) , and the top three incidences were shoulder (28.4%, 233/821) , neck (28.1%, 231/821) , and wrist (25.9%, 213/821) . The incidence of neck WMSDs was statistically significant among different types of work ( P<0.05) . Multiple repetitive operations per minute ( OR=1.70) , torso often maintaining the same posture ( OR=1.61) , turning heads for a long time ( OR=1.58) and frequent heavy lifting ( OR=1.44) were risk factors for the occurrence of shoulder WMSDs ( P<0.05) . Frequent maintenance of the same posture in the neck ( OR=1.91) , repeated operations per minute ( OR=1.87) , shortage of department staff ( OR=1.65) and turning head for a long time ( OR=1.48) were risk factors for the occurrence of neck WMSDs ( P<0.05) . Long-term bending of the wrist ( OR=2.25) , grasping objects tightly ( OR=2.13) , working hard on the upper limbs or hands ( OR=1.91) , shortage of department personnel ( OR=1.84) , repeated operations per minute ( OR=1.68) and the use of vibration tools ( OR=1.51) were risk factors for the occurrence of WMSDs in the wrist ( P<0.05) . Conclusion:The incidence of WMSDs in cabinet factory is relatively high, the occurrence of WMSDs in the shoulders, necks and wrists is more serious. Reasonable labor organization and reducing the load of poor ergonomics in the workplace, can reduce the occurrence of WMSDs in production workers.

OBJECTIVE: To investigate the prevalence and influencing factors of work-related musculoskeletal disorders(WMSDs) among workers in a cement plant. METHODS: A total of 196 workers in a cement plant were selected as study subjects using a judgment sampling method. A revised Musculoskeletal Injury Questionnaire was used to investigate the occurrence of WMSDs in workers in the past year. RESULTS: The detection rate of WMSDs in different parts of the body of workers in the cement plant was 18.4%-32.1%. The detection rates of WMSDs in all parts of the body from high to low was as follows: shoulder(32.1%), neck(30.6%), upper back(24.0%), ankle/foot(24.0%), lower back(23.5%), hip/thigh(22.4%), wrist/hand(21.4%), elbow(18.4%), and knee(18.4%). Multivariate logistic regression analysis results showed that keeping the neck in the same posture for a long time was a risk factor for neck WMSDs [odds ratio(OR)=2.29, P<0.05). Frequent turning around was a risk factor for WMSDs on the neck and lower back(waist)(OR were 3.06 and 3.32, P<0.05). Maintaining the same posture for a long time on the back was a risk factor for shoulder and upper back WMSDs(OR were 3.22 and 2.34, P<0.05). Hard work was a risk factor for shoulder and upper back WMSDs(OR were 2.60 and 2.58, P<0.05). Driving a vehicle was a risk factor for lower back(waist) and ankle/foot WMSDs(OR were 2.54 and 3.17, P<0.05). Carrying objects heavier than 20 kilograms and frequent overtime working were risk factors for ankle/foot WMSDs(OR were 3.03 and 2.54, P<0.05). CONCLUSION: The most frequent parts of the body having WMSDs in the cement production workers are shoulders and necks. Occupational factors(turning around or keeping the same posture of neck and back) are risk factors of WMSDs on shoulder and neck.

OBJECTIVE: To explore the influencing factors of neck work-related musculoskeletal disorders( WMSDs) and their effects in airport porters. METHODS: A total of 413 airport porters were chosen as study subjects using judgment sampling method. Chinese version of Musculoskeletal Questionnaire was used to investigate the prevalence of WMSDs.Then structural equation model was constructed and used to analyze the influencing factors of neck WMSDs. RESULTS: The prevalence of neck WMSDs in airport porters was 37. 3%( 154/413). Postural load,mental workload and length of service had a direct effect on neck WMSDs of porters( path coefficients were 0. 405,0. 166,0. 296,P < 0. 05),and mental workload also had an indirect effect on neck WMSDs through postural load( path coefficient was 0. 103,P < 0. 01).CONCLUSION: Posture load,mental workload and length of service are risk factors of neck WMSDs in airport porters.