Bioelectical Impedance: The Basics for Coaches, Wrestlers, and Athletic Trainers  

Alan C. Utter Ph.D., M.P.H., FACSM
Associate Professor of Health and Exercise Science
Appalachian State University

What is it and how does it work?
One of the newer methods available to assess body composition in wrestlers is known as bioelectrical impedance analysis (BIA). BIA was developed in the 1960s, and has emerged as one of the most popular methods for estimating relative body fat. A safe electrical signal is generated and passed through the wrestler being measured. BIA measures the impedance or resistance to the electrical signal as it travels throughout the body.  Resistance to the electrical signal is greater in fat mass than muscle mass, simply because fat mass is not a good conductor of electricity due to its relatively low water content.   BIA is safe and does not hurt. In fact, the signal used in the body fat monitors can not be felt at all.

The Tanita Corporation (www.tanita.com) has patented a revolutionary new way of measuring BIA that is fast, easy to use, non-intrusive and includes a precision ?legal for trade? scale making this a simple one step process (See Figure). In other words there is no need to purchase a scale and body composition equipment separately. The retail cost of the combined body composition analyzer and ?legal for trade? scale is $1,695.00. It is worth mentioning that members of the National Wrestling Coaches Association receive a 10% discount on Tanita BIA scale. The Tanita BIA scale in addition to calculating percent body fat will also automatically calculate the wrestler's minimal wrestling weight at a predetermined body fat percent. A report of all the results are printed in less than a minute of which the wrestler then can take with them for his or her records.

How well does bioelectrical impedance perform?

                Based on several published studies completed with wrestlers the Tanita BIA machine has comparable accuracy to that of skinfolds. The Tanita machine unlike skinfolds does not require a high degree of technical skill or an trained outside assessor. The Tanita machine simply works by having the wrestler stand on the scale with their bare feet after a few pieces of information (i.e. height, age, etc.) have been entered into a keypad.  It is recommended, as with all methods, that a hydration test such as urine specific gravity be completed prior to its use. The Tanita Corporation has a long standing commitment to conducting high quality research which is exemplified by the development of a scientific advisory board which includes university professors. Use of the Tanita BIA machine also allows for easy monitoring of a wrestler's body composition throughout the season.

Who is using Tanita BIA machines:
The Tanita BIA machines are being used in diverse settings including private clinicians offices, wellness centers, University research centers and hospitals throughout the United States.  In addition, the New Jersey and Indiana state high school athletic associations have recently approved the Tanita BIA as an acceptable method to assess body fat with its high school wrestlers.

Summary:
The leg-to-leg Tanita BIA method has several advantages to be considered within a wrestling population:, 1) it does not requires a high degree of technician skill and therefore is easy to use, and 2) it provides simultaneous measurements of body weight and body composition in a short time period.  The Tanita BIA machine is also very portable, allows for ongoing monitoring, and has a scale that is ?legal for trade?. These advantages may make BIA attractive to high schools that may not have access to trained skinfold assessors or hydrostatic weighing equipment. Over the last 6 years our Human Performance Laboratory here at Appalachian State University has conducted numerous research studies with the Tanita BIA machine, therefore if you have any questions on BIA please feel free to contact me or the National Wrestling Coaches Association at 717-653-8009.

Questions or concerns on the enclosed article:
Dr. Alan C. Utter
email:utterac@appstate.edu
phone: 828-262-3094