Evaluating Lumbar Shape Deformation With Fabric Strain Sensors.

OBJECTIVE: To better study human motion inside the space suit and suit-related contact, a multifactor statistical model was developed to predict torso body shape changes and lumbar motion during suited movement by using fabric strain sensors that are placed on the body. BACKGROUND: Physical interactions within pressurized space suits can pose an injury risk for astronauts during extravehicular activity (EVA). In particular, poor suit fit can result in an injury due to reduced performance capabilities and excessive body contact within the suit during movement. A wearable solution is needed to measure body motion inside the space suit. METHODS: An array of flexible strain sensors was attached to the body of 12 male study participants. The participants performed specific static lumbar postures while 3D body scans and sensor measurements were collected. A model was created to predict the body shape as a function of sensor signal and the accuracy was evaluated using holdout cross-validation. RESULTS: Predictions from the torso shape model had an average root mean square error (RMSE) of 2.02 cm. Subtle soft tissue deformations such as skin folding and bulges were accurately replicated in the shape prediction. Differences in posture type did not affect the prediction error. CONCLUSION: This method provides a useful tool for suited testing and the information gained will drive the development of injury countermeasures and improve suit fit assessments. APPLICATION: In addition to space suit design applications, this technique can provide a lightweight and wearable system to perform ergonomic evaluations in field assessments.

Lumbar posture assessment with fabric strain sensors.

Astronauts are at risk for low back pain and injury during extravehicular activity because of the deconditioning of the lumbar region and biomechanical demands associated with wearing a spacesuit. To understand and mitigate injury risks, it is necessary to study the lumbar kinematics of astronauts inside their spacesuit. To expand on previous efforts, the purpose of this study was to develop and test a generalizable method to assess complex lumbar motion using 10 fabric strain sensors placed on the torso. Anatomical landmark positions and corresponding sensor measurements were collected from 12 male study participants performing 16 static lumbar postures. A multilayer principal component and regression-based model was constructed to estimate lumbar joint angles from the sensor measurements. Good lumbar joint angle estimation was observed (<9° mean error) from flexion and lateral bending joint angles, and lower accuracy (13.7° mean error) was observed from axial rotation joint angles. With continued development, this method can become a useful technique for measuring suited lumbar motion and could potentially be extrapolated to civilian work applications.

Funding of pilot projects in Latin America: a tool for capacity building in occupational health research.

There is a global need for trained researchers who can address the increasing burden of illness and injury and prepare future generations of researchers. Developing countries have a special need for practical, action-oriented interventions to address workplace problems, based on identification of needs and priorities, development of locally available solutions, and consideration of the sociopolitical context of work and how best to translate research findings into policies. Effective translation and application of research products from industrialized nations to developing countries is essential, but differences in the contexts and local realities of other nations limit extrapolating such research. Funding pilot research projects in developing countries is an effective, practical, and useful tool for training new investigators in research techniques and developing collaborative relationships among countries.

A global survey of occupational health competencies and curriculum.

The World Health Organization has identified a worldwide shortage of occupational health professionals, but evidence suggests that the work and education of these professionals vary across countries. This survey examined the professional development of occupational physicians, occupational nurses, industrial hygienists, and ergonomists in terms of practice competencies and academic curriculum. Of 89 countries that received the survey, 48 (54%) responded. Important differences in competencies and curricula were identified for all groups. More competencies were identified more frequently in developed countries. Academic programs existed more often in developed countries, but curriculum contents varied. The study provides a concrete reference point for discussion and development of competencies and curriculum.

Torque Production Using Handwheels of Different Size During a Simulated Valve Operation Task.

Opening and closing valves in industrial facilities often requires operators to use bars and wrenches as levers (cheaters) in order to overcome initial actuation forces. In order to determine more appropriate operational specifications, the maximum torque production capability was measured when 12 male participants used 4 different valve handwheels at 3 different heights and 2 different angles (in relationship to the coronal plane). The results indicate that the participants produced significantly greater torque when the largest of the 4 wheels (40.6 cm diameter) was used than when the medium (22.9 cm), small (20.3 cm), and handled (17.8 cm) handwheels were used. Although the main effect of heights was found to be statistically significant, post-hoc analyses between the heights found them to be, essentially, equal. In addition, the vertical and horizontal wheel orientations were not found to be different. The results are applicable to all industries where handwheels are used and applicable to valve manufacturers for designing operational torque specifications below the values found in this study.

Torque Production Using Hand Cranks in a Simulated Gear-Operated Valve Opening Task.

Hand cranks are used in a variety of industries to actuate valves and in other gear-operated applications. In order to evaluate these types of operations and their compatibility with operator strength capabilities, a rotational dynamometer was used to measure torque production capability of operators using a hand crank at different heights and angles (with respect to the coronal plane). The tests were conducted for both clockwise and counterclockwise rotations using the dominant arm of each test participant. A total of 18 tests were completed by each of five male right-handed test participants. A 0° declination angle, counterclockwise operation, and both 40.65 cm and 60.96 cm heights were found to be associated with the greatest torque production capabilities.