Last week, we looked at the discipline of occupational biomechanics and explained why companies turn to it to reduce workplace injuries. This week, we'll look at the various methodologies used by practitioners of occupational biomechanics.

Methodology Areas

The methodology used by occupational biomechanics practitioners is divided into six general areas:

• Kinesiology
• Modeling methods
• Anthropometrics
• Bioinstrumentation
• Mechanical work capacity
• Motion and time evaluation

Each of these methods is used to monitor, evaluate and determine corrective actions and causes relating to injuries and death in the workplace. Let's take a look at each of them.

1. Kenesiology

Kenesiology is the study of human movement without considering the actions of force. It is an important discipline in understanding biomechanics and biomechanical applications.

Variables in kenesiology are:

• Angular and linear movement
• Velocity
• Acceleration
• Internal and external forces
• Movement.

2. Biomechanical Modeling

Evaluating the capacity of a worker is the prime target of occupational biomechanics and it requires a true understanding of the human body kinematics. Kinematics that involve unrelated experiments would yield little or no useful data when applying this data to a specific segment.

Biomechanical modeling is one method of analyzing the physical criteria needed for specific occupational positions. The modeling can be as simple as writing down the pros and cons and drawing a free body diagram, or as complicated as a 3-D computer animation.

Since work capacity varies greatly, these variables, among others, must be explored, categorized and evaluated as they relate to the position to be filled:

• Genetics
• Age
• Fitness

3. Anthropometrics

Anthropometrics is the study of human body segment measurements of various populations localized and globally. It's said that to design a machine for the average person is to design a machine for no one since there's no such thing as the average person. Machine and automotive designers thus shoot for the 95^th percentile values when researching product liability issues and safety.

When analyzing anthropomorphic data, exercise caution if the source of this data is not known or understood. In earlier times, the only available anthropomorphic data came from the military, which gathered data from robust healthy males and females within a certain age group. This resulted in the skewing of data just as would occur if one tried to determine the average size of a college campus and included all the athletes. This type of information greatly limits the use, analysis and outcomes for ergonomics and biomechanics.

4. Bioinstrumentation

Instrumentation is crucial to the collection and organization of the data necessary for evaluating occupational biomechanics. Measuring devices attempt to report accurate data, including deviations. Repeatability is necessary and is one test of the degree of accuracy. When selecting a measuring device, occupational biomechanic practitioners should look for a device that is:

• Easy to use
• Not overly time-consuming
• Not burdensome
• Reasonably priced for the task and desired results
• Flexible enough to measure multiple joints or motions so that numerous devices are not necessary.

One such device is a Goniometer, which consists of two arms, a level and a round wheel with degree markings. This device is used to measure various ranges of motion of body segments in relation to the long axis. Accelerometers and rotational transducers can also be used. These are usually quite inexpensive and meet the additional criteria

Conclusion

Next week, we'll look at how mechanical work capacity and motion and time are measured, and what occupational biomechanic practitioners do with this information.

BEWARE OF LOVE

A Valentine's Day JHA

Few activities pose greater hazards than falling in love! It all starts with a fall. Those who fall deepest in love fall hardest. When love enters your life it takes your breath away. Not only do you lose the ability to breathe, you risk breaking a vital organ - your heart. Cupid's arrow can leave permanent scars. And then there's the whole kissing thing. Think of the germs!

Music makers and singers are particularly adept at recognizing the hazards of love. Here is a brief quiz to see if you can figure out the songs from which the following hazards derive. Good luck:

NAME THAT TUNE

Songs that Reveal the Hazards of Love

1. What happens when a sweetheart doesn't use a lifeline.

2. What happens when you let a love song go unguarded.

3. Why love and fire shouldn't mix.

4. Why sweethearts needs respirators.

5. Proof that sweethearts are prone to risky behavior.

6. Simply put: Why you should stay away from love.

Answers:

1. I Fall to Pieces, by Patsy Cline

2. Unchained Melody, by Hy Zaret

3. Smoke Gets in Your Eyes, by Otto A. Harbach

4. You Take My Breath Away, by Claire Hamill

5. Absence of Fear, by Jewel Kilcher

6. Love Hurts, by Boudleaux Bryant

Based on this evidence, on Valentine's Day, we should all wear fall protection, a respirator and safety goggles. And stay away from persons evoking strong emotions.

MEET THE REAL ST. VALENTINE

St. Valentine: Lost his head for love.

The historical personage after whom the day of love was named was a priest who lived in Rome in the third century A.D. at the height of the persecutions against Christians. Legend says that Valentine performed secret marriages in defiance of Emperor Claudius II's ban on marriage. Claudius enacted the crazy law to aid in army recruitment efforts - you see, single men had fewer qualms about joining up than men with a wife and kids. Anyway, Valentine got caught and was thrown into the dungeon.

The inmate became a magnet for young visitors smitten with love, among them the daughter of one of his guards. The two would sit in Valentine's cell and talk for hours. Valentine preached the importance of love. On the day he was led off to be beheaded - February 14, 269 - he wrote his friend a little note, thanking her for her friendship and loyalty. The note was signed "Love from your Valentine." It was a hallmark moment.

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