|
|
|
Scientific Proof
|
On November 22, 1994 testing began at an independent laboratory in Cincinnati to prove PersonaGrip's effectiveness...
The results were startling...
PersonaGrip was scientifically proven to reduce the grip effort by over 54%!
PersonaGrip has the ability to reduce the amount of grip force required to operate something that is trying to slip in your hand.
|
| How EMG Works
A male test subject was instrumented with amplifier-type EMG sensors that measure the electrical activity in a muscle while minimizing the effects of stray electromagnetic interference.
The output traces were designated:
ED - Extensor Digitorum measures the "opening/closing force" of the fingers on an object. This muscle is located along the top of the forearm.
FPL - Flexor Pollicis Longus measures the "closing/opening force" of the thumb on an object. This muscle is located under the base of the thumb in the forearm.
FDS - Flexor Digitorum Superficialis measures the "closing/opening force" of the fingers on an object. This muscle is located along the underside of the forearm.
The amount of force exerted by the hand is indicated on the graphs as a deviation of the corresponding trace from its zero position, a.k.a. the resting phase.
Exertions were held for five seconds to a predetermined level chosen as a realistic medium-high force encountered in everyday work that would place an average male worker at risk for carpal tunnel syndrome in the high-force category.
No effort was made to optimize test results of any trace for conditions with or without custom-molding. These tests were designed to represent realistic real-world situations.
|
| Torque, Linear Force, & Compression Tests
Using a Lido Work Simulator, a standard right-hand tightening torque was applied to the simulator handle. This supination of the right hand twisted the handle with the hand in the neutral position; that is, the angle of the forearm to the upper arm was approximately at a right angle and the hand was in a natural, untwisted position. Twenty-seven inch-pounds was chosen as the realistic torque value. A pliers-type test was performed second, followed by a 20-pound pull-down test, all from the neutral position. |
Comparative Results
|
Note: All electromyography tests were performed within scientifically accepted procedures used by NIOSH/OSHA and universities worldwide.
Baseline data was established using the standard handle provided on the simulator. Prior to testing, the handle was cleaned with isopropyl alcohol to optimize its coefficient of friction. In each case, two five-second exertions were used to establish baseline data. Muscle groups can be interpreted visually before and after custom-molding on the superimposed graphs; custom-molded traces appear beneath baseline traces.
|
| Linear Force
Using a summation of the average number of deviations from resting for all exertions of the three muscle groups, the results show the force required to maintain the 20-pound pull fell from an average of 5.75 deviations from resting phase for the unmolded handle to 2.63, a savings of 54.3% with PersonaGrip.
Torque
Using the same statistical technique for the 27 in.-lbs torque test, the results compare 10.6 with 6.0 deviations, a savings of 43.5% with PersonaGrip.
Compression
The pliers-type test showed only a small improvement; however, the test subject noted that the molded handle was considerably more comfortable and easier to use.
Summary
The PersonaGrip custom-moldable handgrip produced significant grip-force savings in work situations where the tool had a tendency to slide across the hand. In compression-type situations, the test subject noted improvements in comfort and ease-of-use. |
Where did the force go?
|
The chart shows that overall input force decreases when a worker can relax his/her grip. Notice that the WORK force coming OUT of the tool remained the same.
This reduction in effort was due to the fact that the worker no longer relied on pure friction to control the tool, but instead had the additional benefit of being geared to the tool with a tackified, conforming material.
In essence, the work out of the tool remained the same (shown in red), but the total effort that went into the tool reduced since the force required to control the tool (shown in green) dropped considerably due to the extra leverage provided by PersonaGrip's gearing effect. |
|
|
When this data is combined with a previous NIOSH finding regarding a worker's risk for carpal tunnel syndrome in situations where both high-force and high-repetition are present, custom-molding a worker to a tool and training them to use less force can mean substantial benefits to both employer and employee alike.
According to their study in 1987, NIOSH reported the risk of carpal tunnel syndrome can be five-to-ten times less if the worker is able to operate below the high-force risk threshold while continuing to operate above the high-repetition risk threshold.
So, by eliminating the high-force risk factor, factories can maintain or actually improve current production levels while reducing significantly the risk for carpal tunnel syndrome for a worker previously exposed to both risks.
This is huge. Think about it for a minute before you read on.
|
|
Vibration Cancellation
Do The Math!
|
In 1992, E. Michael Shipulski of Worcester Polytecnic University glued accelerometers to fingernails of test subjects and found that less vibration was transmitted into the hands of workers who used less grip force to operate vibrating tools equipped with custom-molded grips.
While this might seem obvious to you, it is an important quantification that finally considers the visco-elastic properties of the human hand's interaction with the tool.
This user-invoked isolation mode of vibration reduction occurs so long as the worker uses less grip force to complete the task. As demonstrated in this study, PersonaGrip provides an opportunity for workers to use less grip force when completing a task thus reducing transmitted vibration. |
| Case Histories & Comment
PersonaGrip custom-moldable handgrips can be found on IndyCar, Formula One, Unlimited Hydroplane, and NASCAR steering wheels, at the U.S. Olympic cycling team, the FBI's Special Weapons, and numerous assembly lines worldwide. Virtually all have reported dramatic reductions in stress and fatigue, as well as improvements in accuracy, comfort, and power.
This EMG study was the first quantitative closed-loop, laboratory proof that PersonaGrip can reduce the amount of stress on the human body's upper extremities. There is now little doubt that PersonaGrip is a key element in solving the complex puzzle of cumulative trauma disorders.
PersonaGrip is both hardware and software. The handgrip is the hardware, and end-users provide the three-dimensional software.
PersonaGrip's Total Design Freedom places the most critical element of the human/machine interface - The Grip - in the hands of the one who knows best: The End-User.
Used properly, we feel that this new, innovative application of composite thermoplastic technology can help millions of people lead healthier, more productive lives for years to come.
For more information, Call Toll-Free
(800) 280-GRIP
|
Disclaimer: Since EMG tests have shown that PersonaGrip can reduce grip effort by over 54%, we let YOU Do The Math! However, no claim is made concerning PersonaGrip's ability to prevent Cumulative Trauma Disorders...for a few good reasons: At PersonaGrip, we have not yet mastered Divine Intervention...not yet anyway. And, until we find a way to control the voluntary muscular activity inside someone ELSE'S arm, it is understood that it is only through a compliant user who agrees to take advantage of being able to relax his/her grip, that any benefits may occur. Besides, no studies have shown that anyone can be miraculously healed simply by using PersonaGrip..at least, not YET anyway! So there.
|
| Home | Grip Kits | Grip Theory | Industrial Financial Realities | Industrial Ergonomics | OEM Licensing |
| Customer's View Point | Applications | Prototyping | Steering Wheel Conversions | Design Tips |
| Scientific Proof | Order Form | FAQs - Answers | History | Contact Us |
Disclaimer
PersonaGrip, Inc.
Copyright © 1996-2008 - All Rights Reserved
|
|
