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Despite the widespread popularity of tattoos in the U.S. and worldwide, little consideration has been given to the occupational risk factors that tattoo artists face. Tattoo artists are exposed to many of the same risk factors faced by occupations such as dentistry and cosmetology, including prolonged static work postures and sustained gripping of hand held tools. However, no research has evaluated the extent to which the tattooing profession is adversely affected by its occupational demands. Utilizing a survey of tattoo artists, this research sought to benchmark the prevalence of symptoms commonly associated with the development of musculoskeletal disorders. The survey results revealed that tattoo artists experience high levels of discomfort in the lower back, neck, shoulders, and upper extremities and that these levels significantly exceed discomfort reported in professions that expose workers to similar ergonomic risk factors.

The purpose of this work was to develop a protocol and a related computer application, herein called the Hose Insertion Program, which predicts human insertion capability for flexible hoses as a function of worker, hose, and task factors. The protocol is based on previous studies of hand strength, posture, friction, and hand clearance, and provides the logic for the program's algorithms. To demonstrate and evaluate the program, seven different hose insertions were selected from an automobile assembly plant. After modeling the whole body forces capable using human modeling software, raw data from these insertions and the output from the human modeling software were entered into the Hose Insertion Program. Because assembly operators were observed performing these insertions, it was hypothesized that the program output would indicate that the “insertion force capable” would be greater than “insertion force required” for both whole body and coupling force for the gender and approximated size/strength percentiles observed at the plant. Such an output would mean that the program accurately predicted that these operators were able to perform the hose insertion. For whole body push forces modeled in human modeling software and then entered into the Hose Insertion Program, all 7 outputs were accurate in stating that the operators were capable of performing the task. Of the 7 “insertion force capable” output opportunities for coupling forces related to the observed insertion operations, all 7 outputs were accurate in stating that the operators were capable of performing the task.

Objective: A study was conducted to measure the effect that restricted hand access had on perceived difficulty ratings during simulated hose insertion tasks. Background: Insertion tasks have been identified by workers as physically demanding. Spatial limitations around the flange may affect the ability of the workers to successfully perform the insertion task. Methods: Six male and six female subjects pushed a rubber hose onto a stationary flange under conditions of limited hand access during simulated insertions. Results: The highest difficulty ratings were recorded when an obstruction was lateral to the flange. The overall difficulty rating was positively correlated with posture and force ratings. Conclusion: The location and number of obstructions is an important factor in how the subjects perceived the difficulty of the task. Application: The results of this study can be applied to the future design of insertion-type tasks and methodologies for subjectively assessing hand clearance.

A 3-dimensional kinematic model of the hand was developed. The model predicts hand posture using a simple contact algorithm, which detects a contact between hand segments and the object. Using the 3-dimensional kinematic model of the hand, we estimated grasp envelopes because the space requirement for a specific task is an important aspect to be considered in the task's design stage. For this purpose, two hose insertion methods – a straight method and a rotation method – were simulated. The simulation results were compared favorably with the experimental studies by the previous researches. The model can be used to estimate grasp envelopes for varying hand sizes, object sizes, object shapes, and grip types. The model gives useful and practical information about the grasp envelope to the engineers who design parts or work space.

Hand posture prediction is an important means of assessing specific task designs prior to subject user trials or actual production. The objective of this study was to estimate the effect of a set of task variables on the observation of hand actions during hose installation tasks in automotive assembly operations. From video recordings of 51 jobs, 124 hand actions were identified. Of these, 50 grasping postures, 70 pinching postures and four non-prehensile postures were observed as the dependent variables. Chi-Square tests revealed significance (p

This paper describes the results of a study that investigated the exposure of workers in a foundry to vibration and related physical stresses. The primary objective of this research was to show that use of vibrating tools in the foundry involves exposure not only to vibration, but also to physical stresses both while the tool is running and while it is not running. Four types of tools were investigated: (1) small handheld grinders, (2) scaling hammers, (3) inline hammers, and (4) chipping hammers. The paper describes the characteristics of these tools with respect to physical work factors such as muscle load, upper extremity posture, hand repetition, and exposure to hand/arm vibration. The analysis is based on the use of instrumentation as well as the use of observational methods to quantify the physical work elements. With the exception of the grinders, all the tools investigated in this study produced vibration levels that limited their time of acceptable use, according to published guidelines. In addition to vibration exposure, workers experienced high peak muscle loading, medium to high levels of hand repetition, and extreme or awkward posture of the elbow and shoulder. All tools met or exceeded published recommendation limits for hand activity level. Relevance to industry The use of vibrating tools is common in many industrial settings. This paper describes how, in addition to the stress imposed by hand/arm vibration, workers who use these tools are exposed to other physical stresses such as hand repetition, forceful exertions, and extreme or awkward posture.