Analysis Introduction

This section gives some background information on the analysis of working postures in the workplace. It also describes the analyses types available in Human Activity Analysis.

The Ergonomic Tools toolbar includes four types of analyses:

RULA analysisLift/Lower analysisPush/Pull analysisCarry analysisBiomechanics Single Action Analysis

Some analyses require you to record two postures (initial and final posture) while others use the current posture of the manikin as a base for the analysis.

As soon as the postures are set and recorded (if necessary) you can call each guideline individually and apply the analysis. The result of each analysis will appear at the bottom of the corresponding analysis window. Each dialog box allows you to specify the criterion required for that specific task such as duration and frequencies.

Note that all the analyses are real-time based. This means that if you modify the selected manikin's posture, the current analysis score will automatically be updated.

Note: You must select one manikin in the scene to be able to conduct the analysis.

RULA analysis The RULA (Rapid Upper Limb Assessment) system was developed at the University of Nottingham's Institute for Occupational Ergonomics (Reference: Lynn McAtamney and E. Nigel Corlett, RULA: A Survey Method for the Investigation of Work-related Upper Limb Disorders). It was developed to investigate the exposure of individual workers to risks associated with work-related upper limb disorders.

Lift/Lower analysis

In the Lift/Lower Analysis, you can choose between three guidelines: NIOSH 1981, NIOSH 1991, and Snook and Ciriello. These three guidelines require the use of an initial and a final posture in order to complete the analysis. A brief description of each guideline follows.

NIOSH 1981 In 1981, NIOSH (National Institute for Occupational Safety and Health) published an algebraic equation for analyzing two-handed symmetrical lifts. The lifting is based on a two-handed symmetrical lift with no upper body twisting, and the distance between hands is less than 75 cm (30 inches). This analysis requires a good coupling between the load and the hands as well as between the shoes and the floor surface.

NIOSH 1991 The NIOSH 1991 equation also known as "the revised lifting equation" deals with two-handed manual lifting tasks. The equation handles a certain level of asymmetry. This analysis assumes an adequate coupling between the shoes and the floor surface.

Snook and Ciriello The Snook and Ciriello lifting and lowering analysis tool is based on a study done by S. Snook and V. Ciriello. As with the NIOSH equations, this analysis is based on two input postures. The lifting is based on a two-handed symmetrical lift. The action (lifting or lowering) is determined by the displacement of the load in the scene.

There are three levels of lifting and lowering with approximately 30 inches between each.

from floor to knuckle height from knuckle height to shoulder height from shoulder height to arm reach The horizontal distance is calculated from the chest to the mid-part of the

hand grasp.

Push/Pull analysis The Snook and Ciriello pushing/pulling analysis tool is based on a study done by S. Snook and V. Ciriello at Liberty Mutual Insurance Company. This analysis allows you to compare actual data for a "pushing/pulling" task to what is considered as a safe force to perform that task.

There are 3 steps defined for the vertical height of hands for the pushing task:

from floor to 25 inches from floor to 35 inches from floor to 53 inches

There are six predefined distances for push:

7, 25, 50, 100, 150, and 200 foot push

The gender as well as the vertical height of hands are extracted from the selected manikin in the scene.

Carry analysis The Snook and Ciriello carrying analysis tool is based on a study done by S. Snook and V. Ciriello at Liberty Mutual Insurance Company. This analysis allows you to compare actual data for a carrying task to what is considered as a maximum acceptable weight of carry to perform that task.

This analysis considers two vertical height distances of hands for the carrying task:

For males: from floor to 31 inches, from floor to 44 inches For females: from floor to 28 inches, from floor to 41 inches

The manikin gender as well as the distance value for the hands are extracted from the selected manikin in the scene.

Biomechanics Single Action analysis

This ergonomic tool measures biomechanical data on a worker in a given pose. From the current manikin posture, the Biomechanics Single Action Analysis tool calculates and outputs information such as the lumbar spinal loads (abdominal force, abdominal pressure, body movements) and the forces and moments on manikin joints. All the output incorporated in the model are based on research results and algorithms published by the scientific community.

The forces (loads) acting on the manikin's hands are taken into account in the biomechanical analysis; these forces represent the load of carry, push, lift/lower, or pull, depending on the scenario, and are available for the hands only. Both the Load Properties and the Biomechanics Single Action Analysis dialog boxes can be open at the same time. The last analysis is updated when the load is modified.

Ergonomic Tools ToolbarThe hyperlinks below link to the procedures that describe how to use the commands in the Ergonomic Tools toolbar.

Ergonomic Tools

RULA AnalysisSee RULA Analysis

Lift-Lower AnalysisSee Lift-Lower Analysis

Push-Pull AnalysisSee Push-Pull Analysis

Carry AnalysisSee Carry Analysis

Biomechanics Single Action AnalysisSee Biomechanics Single Action Analysis

RULA Analysis

This task describes the RULA analysis procedure using the RULA Analysis dialog box.

For more information on RULA analysis, see the Analysis Introduction in the Getting Started section.

In the IK Behavior panel, the Optimize Criteria allows you to choose to optimize the posture according to either Postural Score or RULA Analysis. This option will be in effect when IK mode or Reach mode is used, as well as when the IK solver is called to resolve a constraints update.

By default, the None button would be selected. Only one of the three options can be available at the same time.

When the Postural Score is ON, then the IK will always internally refer to the Postural Score and try to find the best score for each segment involved in the IK chain being manipulated. This would have required you to apply preferred angles to these segments, before using the optimize capability. If no Preferred Angles are applied to the Manikin, then the Postural Score option would be grayed and made unavailable.

When RULA is selected, then the IK would use the RULA internal preferred angles calculation (that lead to a global score when RULA is used inside the appropriate Human Activity Analysis command) to lead to an optimized posture of the involved segments during manipulation involving the IK solver. Here you do not need to explicitly apply Preferred Angles to the segments of the Manikin.

However, a Human Activity Analysis license must be present in his current configuration. If this is not the case, the option for RULA would be grayed and made unavailable.

Select the Launch RULA Analysis from the Ergonomic Tools toolbar. The RULA Analysis dialog box appears when the Manikin is selected. The dialog box has the following fields:

Side: Select the side of the manikin that will be analyzed.Parameters - Specify settings that are not automatically set.Score - Displays the score obtained by the analysis.Details - Displays the details of the analysis

Side: Use the two toggle buttons to select the side of the manikin that will be analyzed.Parameters

Use the options in this zone to specify settings that cannot be set automatically.Posture Three types of postures are predetermined:

Static Intermittent Repeated

Select the one that best describes the worker's situation.

Repeat Frequency The Repeat Frequency can not be manually edited. It is automatically set depending on the selected Posture option. This parameter is used to determine the task frequency.

Intermittent = < 4times/min Static and Repeated = > 4times/min

Arm supported/Person Leaning

Arms are working across midline

Check balance

Select one or more of these options to provide additional information that may affect the output of the RULA analysis.

Load Use this field to specify the weight of the manipulated object. Select the arrows to increase or decrease the weight or use the keyboard to directly type a value into this field.Note that the Loads created with the "Insert a new Load" command are not taken in account in the RULA analysis.

Score There are two modes for the score display: basic mode and advanced mode.Basic mode

The data displayed in this mode is the final score accompanied by a colored zone. The color of this zone changes from green to red according to the final score.

The RULA analysis examines the following risk factors: number of movements, static muscle work, force, working posture, and time worked without a break. All these factors combine to provide a final score that ranges from 1 to 7.

1 and 2: (Green) Indicates that the posture is acceptable if it is not maintained or repeated for long periods of time.

3 and 4: (Yellow) Indicates that further investigation is needed and changes may be required.

5 and 6: (Orange) Indicates that investigation and changes are required soon.

7: (Red) Indicates that investigation and changes are required immediately.

Use the More button to switch from the basic mode to the advanced mode.

Advanced mode

The data displayed in the basic mode is also displayed in the advanced mode. The advanced mode, in addition, also displays the intermediate scores. Some of these scores are obtained by subjective values. In the basic mode, these values are automatically set to default; in the advanced mode you can change these values. The score will then be modified to reflect these new values.

Use the Less button to switch back to the basic mode.

DetailsThe Details section that is displayed when you press the More button presents the score obtained for each section and used to calculate the final RULA score. The parameters of six of these segments can be edited:

Upper arm:Shoulder elevationArm abduction

Forearm: Arm rotation

Wrist: Wrist deviation

Wrist twist: Wrist twist

Neck: Neck twistNeck side-bending

Trunk: Trunk twistTrunk side-bending

For each of the parameters, you have a choice of three options: Auto, Yes, and No.

Auto:

(No or Yes): RULA is using the parameters defined in the RULA Parameters field (Tools->Options->Ergonomics Design & Analysis) to determine the state of a specific segment, i.e., Shoulder in elevation or not, Arm in abduction or not, etc.

Yes: By selecting Yes, you force RULA to consider that the segment is at the specified state (elevation, abduction, etc.) no matter what the posture of the selected manikin is.

No: By selecting No, you force RULA to consider that the segment is not at the specified state (elevation, abduction, etc.) no matter what the posture of the selected manikin is.

These intermediate scores, represented by a number and a color, are used to calculate the final RULA score. The following table indicates the score range for each segment as well as the associated color.

SegmentScoreRange

Color associated to the score

1 2 3 4 5 6

Upper arm 1 to 6

Forearm 1 to 3

Wrist 1 to 4

Wrist twist 1 to 2

Neck 1 to 6

Trunk 1 to 6

For viewing the RULA Colors on the manikin, please see Segment coloring for RULA Analysis.

Segment Coloring for RULA Analysis

This will analyze and visually review the postures of the manikin that are not fulfilling the RULA requirements in the 3D Geometry window. This enhances the analysis performance before going into a more detailed analysis of some specific postures.

You will be able to visualize the colors given by the RULA analysis on the manikin segment, without opening the RULA analysis dialog box. It provides another tool to visualize analysis results.

You will be able to control the display of colors for the RULA analysis on the manikin by setting the right coloring parameters in the manikin's coloring properties (by opening the Properties panel). There are two types of coloring available for the RULA analysis.

The first type, General will analyze and color the manikin body in the two broad categories specified by RULA: Wrist Arm and Neck, Trunk and Leg.

The second type, Detailed, will show colors on each individual manikin segment analyzed by RULA. The table below illustrates the correspondence between a score in the analysis and the

body part to be colored.

Please note that only one arm and one leg (from the same side) will be colored at a time, in order to respect the RULA analysis input guidelines.

1. In the Human Activity Analysis workbench, with a manikin inserted, move the manikin's segments in a similar position.

2. Right-click on the Manikin (Manikin1) in the PPR tree, and select Properties

3. In the Properties dialog box, select the Coloring tab, and select the Active the functions.

4. Select the data information as shown.

5. Select the Apply, OK.

6. The RULA information is transposed onto the Manikin's surfaces.

The following coloring parameters will be saved with the manikin:

Analysis for coloring.

Show Colors (None, All or All but maximum score)

Elements to color (segments and/or surfaces)

Type of coloring for RULA (General or Detailed).

The options titled Show Colors and Elements to color remain the same. The Degree of Freedom section will be available only in the context of the Postural Score coloring. Likewise, the section (at the bottom of the window) will be available only in the context of the RULA Analysis coloring.

The type of coloring for RULA will be accessible via the Type combo.

This combo is specific to the RULA analysis. The choices underneath that combination will be General and Detailed, as explained.

Only one type of coloring can be active at a time (Preferential Angles or RULA). Only one side of the body will be colored at a time, since RULA analyzes one side at a time.

For more information on the RULA method, please read the following page that explains the steps for manually carrying the RULA evaluation.

RULA Employee Assessment Worksheet

For more information about customization, please see Customizing RULA Specifications.

Human Activity Analysis

This page describes how to customize the specifications for the RULA (Rapid Upper Limb Assessment) Analysis.

You can customize a total of nine parameters, thus influencing the result of the RULA analysis via the Tools >Options menu. These parameters define the threshold values for different degrees of freedom.

The default values for these parameters are shown in the image, below.

Segment to be colored RULA Analysis entry

Upper Arm Upper Arm

ForearmThe worst between Forearm and Wrist Twist.That mean that if Wrist Twist is red,we take this value. Otherwise, we take the Forearm color.

Hand Wrist

Neck (named head) Neck

Trunk Trunk

Thigh and leg Leg

These nine parameters are used to transform the questions involved in the RULA process to angle comparisons. For example, during the calculation of the RULA result the question might be, Is the neck bending to the side? The question is subjective unless a threshold is set. For this particular case, the software compares the value of DOF 2 of the subject manikin's neck with the threshold defined in the RULA settings. If the value of that DOF is greater than 18.375 degrees, then RULA considers the neck to be bending.

If the user determines that 18.375 degrees (default threshold) is not an appropriate value for the neck, this value may be overridden. The new value entered by the user will then be used for the next RULA calculation, and the output will be affected accordingly.

For exporting the data in a report, please see Reporting Capabilities and Reporting Capabilities for RULA in XML format in Human Task Simulation workbench (this will be selectable for activation only if the proper product license check succeeds for this analysis, and the workbench is available).

Manikin Eyes Following the Compass with IK and Reach Mode

This provides a natural behavior for the manikin's vision when it is performing a reach or IK on an object. The vision of the manikin is directed to the object the manikin is trying to pick up, which would be more like a human.

You can explicitly choose which hand is to be the target of the Look At, the left, right, or either hand.That way, you will be able to activate the right option from the start, and will not have to switch back and forth between the IK Mode (or Reach Mode) and the general options page. As a result, the manikin will behave as illustrated below.

In most positioning scenarios, you have to manually do a reach with the line of sight for orienting the head in the direction of the working hands. This will eliminate a step since the reach of the line of sight will be done interactively. You will also be able to choose which type of eyes tracking the manikin will perform: eyes-only or eyes and head.

1. To enable the Look At functionality this has to be set in the in the IK Behaviors Icon. The manikin will look at the compass, when moving their hands.

2. If the Look At option is enabled, as soon as the manikin tries to reach an object, the line of sight will be moved so the manikin can see what it is about to reach. This motion will be similar to the existing reach performed on the line of sight.

3. The manikin will look at the point targeted by the 3D compass.

4. That way, you will be able to activate the right option from the panel, and will have the opportunity to switch back and forth between the various options while inside IK Mode or Reach Mode. Furthermore, the Right and Left selections will allow the manikin to look at

its right and left hand, respectively. As a result, the manikin will behave as shown.In this example, the left hand is being manipulating with IK Mode, but the manikin is still looking at its right hand. To activate the option, simply check the Hand checkbox in the IK Behaviors panel and choose the hand required to be looked at (Right, Left or "Active" hand).

Please note however that this option can work outside the IK and Reach modes. The Look At will be triggered if a permanent constraint is created on either hand:

o Within the IK Mode (or Reach Mode), the manikin will look at the hand specified by the option, depending on the hand on which the compass is located.

o When outside of the IK Mode (and Reach Mode), if this option is kept enabled, it will

look for an active permanent constraint on the hand, when you click the Update icon, the manikin will look at either the right hand or the left hand (if the choice is respectively Right Hand or Left Hand). If Active Hand is selected, the manikin looks at the hand on which there is an active permanent constraint. And if there are active constraints on both hands, the manikin will look at its right hand. If there are no active constraints on either hand, the option will not operate.

To clarify this point, let us assume that the manikin has one constraint on the right hand and one constraint on the left hand. The constraint on the left hand is active whereas the one on the right hand is inactive. Let us say further that the Look At option is positioned on Active Hand, as in the snapshot above. When you update the constraints, the constraint on the left hand will resolve, and the manikin will look at the left hand. If we then activate the constraint on the right hand and update again, the manikin will look at its right hand.

When used outside of the IK this option thus acts as if a hidden constraint existed on the line of sight. And this hidden constraint is resolved with the rest when the manikin is updated.

If the constraints are updated (manually or automatically), this option, if enabled, will trigger the Look At. For example, if the Automatic option of the Tools > Options > Constraint Resolution is enabled and the Forward Kinematics command is used, the manikin will keep looking at its hand. The option ceases to operate only when a permanent constraint is created by the user on the line of sight. A permanent constraint created on the line of sight will have priority over the Look At option.

Furthermore, in simulation (DELMIA Human Task Simulation product), this new Look At option will behave exactly like the other "IK Behavior" options.

5. The IK Behaviors dialog box, selecting the Line of Sight only, will make IK Chains limited to the Line of Sight, blocking all movements of the head.

Lift-Lower Analysis

This task describes the lift-lower analysis procedure using the lift-lower Analysis dialog box.

For more information on lift-lower analysis, see the Analysis Introduction in the Getting Started section.

1. Select the Lift-Lower Analysis from the Ergonomic Tools toolbar. The Lift-Lower Analysis dialog box appears when the Manikin is selected. Depending on the Selected

Guideline, the dialog box changes. With the manikin in the first position, select the Initial button, and the Record bar.

2. Move the manikin to the second position that is to be analyzed, and select the Final button, and select the Record bar. After the Lift-Lower analysis is completed, the Score and Warning are shown.

3. The dialog box for NIOSH 1991.

The fields to choose from are:

Posture

This area of the dialog box has two functions:

Display and choose postures (Initial and Final toggle buttons)Use these two toggle buttons to select which posture you want to record or modify. When the postures are recorded, use these buttons to switch back and forth between the two postures. The manikin in the scene displays the current posture selected.Record or modify the selected posture (Record/Modify push button)Use this push button to record a posture. Use the Initial and Final buttons to select the posture to be recorded. If the manikin's current posture does not respect the lifting task definition, an error message will be displayed with the list of the missing or bad prerequisites.

Guideline From this list, select the guideline to perform the lift-lower analysis. The guidelines available are NIOSH 1981, NIOSH 1991, and Snook & Ciriello.

The Specifications and Scores will change depending on which guideline is chosen.

NIOSH 1981

Specifications

1 lift every: Use this specification to determine lift frequency. Click on the arrows to increase or decrease the value indicated in the text field or directly enter a new value using the keyboard.Duration:Use this field to enter the duration of the work in hours per day. The work is considered:

occasional if the value is one hour or lesscontinuous if the value is 8 hours

ScoreImmediately after the frequency and duration fields are completed, the results are displayed in the Score zone.

Action Limit (AL):This value represents the weight below which the task could be considered as reasonably safe.Maximum Permissible Limit (MPL):This value represents a limit above which the lifting task is considered as hazardous and requires engineering controls.

NIOSH 1991

Specifications

1 lift every:Use this specification to determine lift frequency. Click on the arrows to increase or decrease the value indicated in the text field or directly enter a new value using the keyboard.Duration:Use this field to enter the duration of the work in hours per day. The work is considered:

occasional if the value is one hour or lesscontinuous if the value is 8 hours

Coupling condition:Use this function to quantify the quality of the hand-to-object. The coupling quality is classified as Good, Fair, and Poor.

Good - a comfortable grip in which the hand can easily wrap around the objectFair - a grip in which the hand can be flexed about 90 degrees.Poor - when the the object is hard to handle (irregular, bulky, sharp edges, etc.)

Object weight:Use this field to enter the load weight. This value is used for the lifting index calculation.

ScoreImmediately after the frequency and duration fields are completed, the results are displayed in the Score zone.

OriginThis result is based on the initial posture of the manikin.

Recommended Weight Limit:The RWL is the load weight that healthy workers can lift over a certain period of time without risk.Lifting Index:The LI provides a relative estimate of the level of physical stress.

Destination This result is based on the final posture of the manikin.

Recommended Weight Limit:The RWL is the load weight that healthy workers can lift without risk.Lifting Index:The LI provides a relative estimate of the level of physical stress.

Today in the Human Activity Analysis workbench, the NIOSH 1991 Lift/Lower analysis outputs the Recommended Weight Limit (WRL), and the Lifting Index (LI) in the Score section of the Lift/Lower Analysis panel.

This will allow you to easily view the various multipliers (intermediate results) that are used in the NIOSH 1991 Lifting Equation, and to copy/paste them in another text editor, for future reference. The goal here is to provide more pertinent information.

To attain these results of recommended weight limit and lifting index from the manikin posture, we use the equations prescribed in the literature regarding the NIOSH 1991 study. The text below presents these equations.

But because these factors carry substantial information on their own, and because this information is supplemental to the information given by the final output (WRL and LI), there is a need to display these values as well. This way, you can be fully informed of a particular factor change, say the frequency multiplier, and can appreciate precisely how any of the intermediate factors influences the final result.

The following two equations are taken verbatim from the brochure entitled: "Applications Manual for the Revised NIOSH Lifting Equation", U.S. Department of Health and Human Services, Cincinnati, Ohio, January 1994:

RWL = LC * HM * VM * DM * AM * FM * CM

L LI = ____

RWL

Here, we see that a few intermediate variables ("LC", "HM", and so on) are

needed, and calculated internally, in order to produce the two main results of the analysis. These variables are:

A load constant (LC)The horizontal multiplier (HM)The vertical multiplier (VM)The distance multiplier (DM)The asymmetric multiplier (AM)The frequency multiplier (FM)The coupling multiplier (CM)The load weight carried by the subject (L)

This way, you can be fully informed of a particular factor change, say the frequency multiplier, and can appreciate precisely how any of the intermediate factors influences the final result.As this lack of information prevents you from understanding how the analysis operates.

Snook & Cirielloo

Specifications

1 lift every:Use this specification to determine lift frequency. Click on the arrows to increase or decrease the value indicated in the text field or directly enter a new value using the keyboard.Population sample:Three population percentiles are provided: 90th, 75th, and 50th. These percentiles represent the percentage of the population able to perform the task safely. The selected percentile takes the manikin gender into account.

Score Immediately after the frequency and population sample fields are completed, the results are displayed in the Score zone.

Maximum Acceptable Weight:The maximum acceptable weight is defined as the weight that the selected population can handle with reasonable safety.

Report See Reporting Capabilities

Push-Pull Analysis

This task describes how to execute a Push-Pull Analysis using the Push-Pull Analysis dialog box.

For more information on Push-Pull Analysis, see the Analysis Introduction in the Getting Started section.

1. Select the Push-Pull Analysis from the Ergonomic Tools toolbar. The Push-Pull

Analysis dialog box appears after the Manikin is selected.

2. The Push-Pull Analysis dialog box contains the Snook & Ciriello guideline. This dialog box has the following fields:

Guideline

From this list, select the guideline to perform the analysis. In this analysis, only one guideline is available.

Specifications

o 1 push every:Use this field to determine the push frequency. Select the arrows to increase or decrease the value indicated in the text field or directly enter a new value using the keyboard.

o Distance of push:Use this field to specify the distance of the push. Select the arrows to increase or decrease the value indicated in the text field or directly enter a new value using the keyboard.

o Distance of pull: Use this field to specify the distance of the pull. Select the arrows to increase or decrease the value indicated in the text field or directly enter a new value using the keyboard.

o Population sample:Three population percentiles are provided: 90th, 75th, and 50th. These percentiles represent the percentage of the population able to perform the task safely. The selected percentile takes the manikin gender into account.

Score Immediately after the Specification fields are completed, the results are displayed in the Score zone.

The initial forces are required to initiate the object's motion. As the object begins to move, these forces will decline to a relatively constant level (sustained forces).

o Maximum acceptable initial force:This value expresses the force required to put an object into motion.

o Maximum acceptable sustained force:This value expresses the force required to keep the object in motion.

Warning

Immediately after the Specification fields are completed, the results are displayed in the Warning zone.

Report See Reporting Capabilities3.

Carry Analysis

This task describes how to execute a carry analysis using the Carry Analysis dialog box.

For more information on Carry analysis, see the Analysis Introduction in the Getting Started section.

1. Select the Carry Analysis from the Ergonomic Tools toolbar. The Carry Analysis dialog box appears after the Manikin is selected.

2. The Carry Analysis dialog box contains only the Snook & Ciriello guideline. This dialog box has the following fields:

Guideline This list presents the guidelines available to perform a carry analysis. Only one guideline is available.

Specifications

o 1 carry every:Use this field to determine the carrying frequency. Select the arrows to increase or decrease the value indicated in the text field or directly enter a new value using the keyboard.

o Distance of carry:This specification is used to determine the distance the object will be carried. Select the arrows to increase or decrease the value indicated in the text field or directly enter a new value using the keyboard.

o Population sample: Three population percentiles are provided: 90th, 75th, and 50th. These percentiles represent the percentage of the population able to perform the task safely. The selected percentile takes the manikin gender into account.

Score Immediately after the Specification fields are completed, the results are displayed in the Score zone.

o Maximum Acceptable Weight:The maximum acceptable weight is defined as the weight that the selected population can carry with reasonable safety.

Warning Immediately after the Specification fields are completed, the results are displayed in the Warning zone.

Report See Reporting Capabilities3.

Biomechanics Single Action Analysis

This procedure describes how to use the Biomechanics Single Action Analysis command.

This ergonomic tool measures biomechanical data on a worker in a given pose. From the current manikin posture, the Single Action Analysis tool calculates and outputs information such as the lumbar spinal loads (abdominal force, abdominal pressure, body movements) and the forces and moments on manikin joints. All the output incorporated in the model are based on research results and algorithms published by the scientific community.

The forces (loads) acting on the manikin's hands are taken into account in the biomechanical analysis; these forces represent the load of carry, push, lift/lower, or pull, depending on the scenario, and are available for the hands only. Both the Load Properties and the Biomechanics Single Action Analysis dialog boxes can be open at the same time. The last analysis is updated when the load is modified.

1. In the Ergonomics Tools toolbar, select the Biomechanics Single Action Analysis.

2. In the PPR tree or the 3D view, select a manikin for the analysis.

3. The Biomechanics Single Action Analysis dialog box for that manikin appears, opening to the default Summary tab.

Summary tab

The Summary tab gives general biomechanics information such as:

o L4-L5 Momento L4-L5 Compressiono L4-L5 Joint Shearo Abdominal Force and Pressureo Ground Reaction

L4-L5 Spine Limit tab

The L4-L5 Spine Limit tab displays the evaluation of the posture and whether it exceeds the compression and joint shear limits recommended by NIOSH and the University of Waterloo. The information on this tab can be viewed as a list or as a chart.

Joint Moment Strength Data tab

The Joint Moment Strength Data tab displays the evaluation of the percentage of a worker population that doesn't have the strength to perform a task based on strength studies such as those by Askew, An, Morrey and Chao (1987) for the elbow, Koski and McGill (1994) for the shoulder, and Troup and Chapman (1969) for the lumbar.

This information can be displayed as a chart or as a list.

For a more complete analysis of the human biomechanics Results a new analysis will cover both wrists in flexion-extension and Radial-Ulnar deviation

Reaction Forces and Moments tab

The Reaction Forces and Moments displays, in detail, the reaction forces (N) and orthopedic moments (Nm) proximal and distal segments.

This tab specifically presents many data for each analyzed segments which leads to a wide and long list that need to be so extended that the manikin is hidden. Moreover, having to read through many lines and columns of data can introduce misread errors. A better way to display the results in 3D, each segment results are highlighted in the list when the related segment in the 3D model is selected.At a segment’s selection directly from the manikin, the results panel will update in order to highlight the selected segment.

The results for a given segment can be highlighted in the Reaction Forces and Moments tab by a single selection of it either by a direct selection on the manikin or a segment node selection from the tree.If the segment is not part of the Biomechanics Analysis, no highlighted data will be displayed.

Segment Positions tab

The Segment Positions tab displays information (position, angle, center of gravity, length) about the segments.

Export Results

Use the Export... button to save the biomechanical data in a text file. In the Export results dialog box, select the type of information you want to save and OK.

The biomechanical data is saved as a text file.