Financial Realities of Industrial Ergonomic Theories Dispelling Myths and Setting the Record Straight PersonaGrip's patented composite handgrip technology helps workers avoid costly Cumulative Trauma Disorders (CTDs), such as Carpal Tunnel Syndrome (CTS), by allowing them to relax their grip and still maintaining control of the tool. This was scientifically proven, and already there are several manufacturers including Toyota Motor Manufacturing, Kenworth Trucks, and Harley Davidson administering the technology themselves. Over 2/3rds of IndyCar drivers, the U.S. Olympic Cycling Team, World Champion Racquetball players, and the FBI have been using it for years. Now, the industrial athlete is reaping its benefits. Adjustable handgrips have been around since the late 1800's when Frenchmen would moisten leather grips and leave them out in the sun to create molded grip designs. Today, composite thermoplastic materials make a more user-friendly approach possible. By providing a thermoplastic moldable layer over top of a thermally stable inner core layer, users have a very forgiving, reversible design platform to experiment with their grip designs. Patented Technology The inner core layer provides a thermally stable base for the softer moldable layer on top. It also prevents mold-through down to bare metal so users have a continuous tacky grip surface no matter how deep they mold. From a design standpoint, depending on the ratio of top and bottom layer thicknesses, the degree of moldability can be controlled in specific areas of the grip right from the factory. However, it is the top layer's remoldability that allows users to zero-in on perfect designs. This total design freedom is critical for the technology to work. The Old Paradigm It is a popular misconception among many respected authorities that custom-moldable handgrips don't work. This is simply not true today. We have documented thousands of cases that contradicts this mindset. So, how is it that hundreds of educated professionals have come to this same incorrect conclusion? Through no fault of their own, it is due in part to their lack of persistence with the new composite thermoplastic handgrip material. Perhaps it's also in the nomenclature. There is no doubt that an improperly designed grip might not be optimal in certain situations, but the human body has indicators to signal this condition. A user might think the grip is uncomfortable or unwieldy, too big or too small. Most of these initial reactions arise from the change in the grip itself and the unnecessary death grip they continue to use when operating the tool. PersonaGrip provides a way of allowing workers to relax their grip and not worry about the tool's reaction in their hand. By building up leveraging surfaces in critical areas, workers can use these surfaces to "lean against" at the most potentially damaging moment: impact or final torque. Instinctively, a worker increases grip tension at this moment; however, with proper training and good grip designs, workers can begin to relax their grips and reap the benefits of reduced forearm tension afforded by PersonaGrip. Mysterious Forces PersonaGrip has a proven link to reducing the risk for carpal tunnel syndrome since high-grip force and high-repetition are leading causes for these diseases according to NIOSH. Where do the forces go? There are two forces that go into operating a tool: Control force and task force. Control force is that which is required to guide the tool, and task force is the force that comes out of the tool to do the job. By changing a worker's control mode from pure friction to enhanced friction (i.e., tackifiers) with leverage (i.e., molded), dramatic reductions can occur in the control force component. In fact, recent electromyography tests (EMG) have demonstrated that over half the force going into an operation can be needlessly wasted. In a 20-pound linear force test (where the tool tried to slide out of the hand), a 54.3% reduction occurred with PersonaGrip; in a 27-inch-pound torque test (where the tool tried to twist in the hand), a 43.5% reduction in force occurred. These are serious numbers! Industrial Ramifications In 1987, NIOSH tested the relative importance of certain risk factors including high repetition and high force. They found that, in the situation where both high force and high repetition were present, there was a marked increase in overall risk, as much as five-to-ten times higher. In other words, if a worker is exposed to both high force and high repetition, they are at a five-to-ten times greater risk for carpal tunnel syndrome than a worker who is exposed to just one of these risk factors. Therefore, according to this research, by eliminating just one of these risk factors -- for workers previously exposed to both risk factors -- there could be five-to-ten fold decrease in risk for carpal tunnel syndrome. Certainly, one cannot expect a company to embrace the concept of reducing repetition. That is akin to suggesting a loss in productivity. However, if a high-repetition worker can be trained to use less force in completing a task, and that worker can fall below their threshold that places them at risk in the high-force category, they can maintain -- or actually improve -- productivity while significantly reducing their risk for carpal tunnel syndrome. This is precisely why PersonaGrip is so important today. The New Paradigm Take the molded grip at the bottom of an umbrella found at a drug store. It is a generically designed, molded grip that fits virtually any hand that grabs it. It has finger grooves that follow the natural contour of the average human hand to enhance control. By today's standards, grooving a tool grip is simply too bold. Why? Because it might not fit perfectly every hand that grabs it, and that could mean lost sales. Marketing guys absolutely hate when that happens. So engineers end up designing for the 99th-percentile humanoid; that is, 99 percent of the workers who grab it will tolerate it, and you usually end up with a generic, featureless grip. But there is another dilemma: manufacturers must foresee every possible use and misuse of the tool. The net result is a smooth grip that relies mainly on friction between the operator and the tool for control. Stuck with only that control mode, manufacturers are forced to take Band-Aid approaches to improve the friction by inserting high-coefficient materials in the hand area. It is all a compromise because the end user has no input! Back to Basics High-school physics experiments demonstrate friction by dragging a block of material across a surface with a scale to calculate coefficients of friction. The coefficient is simply a ratio of the force required to drag the block compared with the downward force due to gravity. Theoretically, this fraction cannot exceed one and is usually represented in decimal form. For example, a one pound block with a 0.75 friction coefficient takes three-quarters of a pound to it slide across a particular surface. However, adhesives technology has introduced a relatively new concept. To account for the "stickiness" of a material, stiction factors in the adhesive quality of the mating surfaces so a ratio greater than one can be achieved. In other words, it can take a greater force to drag the block across a surface than the force it exerts downward due to gravity. That is how top fuel dragsters can accelerate beyond "one G" right off the line. Likewise, tackifiers in grip materials help users relax their grip and still maintain control. However, in the case of non-adjustable grips featuring nothing more than a smooth surface to grab, workers must still rely primarily only on friction between their hand and tool for control. This means they must squeeze the tool, no way around it! (NOTE: Comparing this to our friction example, the "squeezing in" is equivalent to the force of gravity...just in case you were wondering). Since most grips offer little or no leverage, if the worker were to remain relaxed at a critical moment, say at impact or final torquing, the tool would more than likely react violently and leave the operator's hands, possibly causing injury.   PersonaGrip solves all this by giving the end user the option of redesigning the grip. So, if the end user has the option to redesign the grip, factories can now start to design in some ergonomic contours and not worry if that one-in-a-hundred customer might not like it. Luckily more and more tool manufacturers are beginning to realize this and adopt PersonaGrip into their product line. However, for those in need of a solution to high grip effort right now, we have Do-It-Yourself Kits available right now. If your needs are in the high-repetition work environment, we have three Industrial Ergonomics Programs available for you right now. | 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