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 Elite athletes are finding that an off-season resistance weight training program is essential for maximizing their performance in-season. For a criterium racer a power training program will enhance their top end speed, anaerobic recovery and sprint.

For road racers and time trialists a strength training program will developmuscle strength to enhance their effective horsepower. The program needs to be geared to those muscle groups which are utilized by the sport, primarily the muscle of the legs with additional focus on the abdominal, back, shoulder and arm muscles. Too much upper body development will be detrimental for competitive cyclists so limited focus is placed on these muscle groups.

Research studies have found that while power training (fast-velocity) will improve both muscle strength and power, strength training (slow-velocity) will only improve muscle strength with little improvements in muscle power. For this reason those athletes desiring an improvement in muscle power, criterium racers in particular, a power training phase needs to follow a base strength training program. To optimize a power training program and reduce the risk of musculoskeletal injury it is best to develop an adequate fitness base with a prior strength training program lasting a minimum of four to six weeks.

Numerous clients I come in contact with would not be considered overweight. Many are physically active and have bodies which in clothing you might easily trade for. Yet they are often frustrated by what we call"skinny-fat". Most lack the solid, hard look of a weight lifter or power athlete. Although many of these individuals are normal weight they lack muscle firmness and tone. This is especially true for individuals who primarily do aerobic exercise like cycling or running.

Frequently, even people who exercise religiously with aerobic activities, find their bodies lack a certain degree of muscle tone. This lack of muscle tone does not only affect their appearance, but also is manifest in a decreased muscle strength. Strength training is becoming a mainstay not only for elite endurance athletes who want to increase their power for surges and a final sprint during a race, but also is being used by individuals interested in weight loss and overall fitness.

The American College of Sports Medicine (ACSM) now recommends two sessions of resistance training per week along with their prior recommendation of three to five sessions of cardiovascular, aerobic exercise for individuals interested in improving their overall fitness. Cardiovascular exercise is no longer the only recommended form of exercise for a healthy population. Physicians and health experts are recognizing the benefits of a balance of cardiorespiratory and muscular fitness for disease treatment and prevention.

Although the frequency and duration of an endurance athlete's weight training workouts are much less than an elite power/strength athlete's would be, the intensity must be as high. Without high intensity workouts the training would be unproductive and not time efficient. Heavy training is necessary to recruit the fast muscle fibers which is necessary to increase both their strength and overall tone. The number of repetitions and speed of movement will determine whether a size, strength or power gain will be attained (see side bar).

Without resistance training the recreational athlete will often fail to utilize the fast muscle fibers. A lack of muscle tone will result from the undertoned fast muscle fiber portion of their muscles. By incorporating several sessions of resistance training into an established aerobic training regimen will body. This type of program followed during the off-season will allow for an overall increase in muscle strength / power along with any desired improvement in muscle tone and appearance.

When designing your resistance program several guidelines should be followed. Strength training, unlike aerobic exercise, should not be performed for the same muscle group on consecutive days. The ACSM recommendation of two resistance training days per week is the minimal recommendation for improvements in strength. For recreational athletes who desire to incorporate strength training into their overall exercise program a three day per week schedule would fit in well to an overall fitness program. More elaborate programs exist for competitive athletes participating in particular sports. For those beginning a new exercise program it is recommended that you first consult your physician and progress gradually into the program.

  SIDE BAR

The adaptation gained from resistance training is determined by the repetition number, speed of movement and weight used during each movement. When training for power, fast, explosive movements should be performed, particularly during the exertion phase of a lift. For strength a slower movement is performed and therefore a heavier weight can be handled. For strength and size increases eccentric muscle contractions are a necessary component and therefore forced reps and negatives need to be included in the program. Only heavy, low repetition training is performed when power or strength increases are desired with little increase in muscle size. A wider range of repetitions and sets are used for those individuals desiring increases in muscle size. The lower repetitions will train the fast muscle fibers while the higher repetitions will train the slow muscle fibers. The speed with which you perform the movement will determine whether you develop explosive power or i

ncreased strength. Repetition maximum (RM) is the designation used in weight training to define exercise intensity. 1RM is the maximal amount of weight you can handle for one repetition of an exercise using proper form. The designation RM denotes the number of repetitions you will perform in proper form with a resistance which allows you to perform only that number of repetitions.

The following guidelines should be followed:

For power adaptations:
       2-6 RM sets at fast movement speed.

For strength adaptations:
        4-8 RM sets at a slow-moderate movement speed.

For size adaptations:
        4-8 and 12-20 RM sets at a slow-moderate speed.

For overall fitness:
        8-12RM sets at a slow-moderate movement speed.

RECOVERY: REPAIRING THE DAMAGE

To master the art of recovery, you'll also have to pay attention to any pain you might feel during or following a workout, because pain from an overuse injury is much different than the soreness that follows a difficult workout. Postponed soreness is symptomatic of a normal response called delayed onset muscle soreness (DOMS). Although it rarely begins during the workout, the soreness more typically appears several hours afterwards and peaks about 24 hours later. An injury, on the other hand, causes pain during the workout. Then it doesn't go away, but usually gets worse.

These overuse injuries are the result of overtraining or of cumulative stress on the body over time. One of the most common overuse injuries is connective tissue damage within the muscle, tendon, ligament or cartilage of the joint, Degeneration of the joint, called osteoarthritis, can become arthritis if left untreated.

The cartilage in our joints are vulnerable to a wide range of traumas that can result in cartilage degeneration. When a joint becomes inflamed, the blood supply to it is reduced, which in turn reduces the ability to repair the cartilage in the joint. In addition, our natural antioxidant enzyme systems break down and free radicals attack the connective tissue. These free radicals can trigger a cascade of events and cause chronic loss of connective tissue structure and function. This problem intensifies as we get older or as our training volume increases. When the vascular system becomes blocked, normal connective tissue repair and maintenance is prevented.

In order to treat the overuse injury effectively, we must protect the connective tissue against further destruction with rest. At the same time, we need to stimulate the anabolic restoration of connective tissue by supplying the body with adequate nutrients. Contrary to popular belief and use, adequate nutrients are not over-the-counter drugs. The body manufactures compounds called chondroprotective agents, which naturally regenerates cartilage and healthy connective tissue. Aging and overtraining, however, disrupt the body's ability to use the body's own chondroprotective agents. For years, European doctors have had great success with nontoxic natural therapies to treat osteoarthritis and other connective tissue traumas. Americans, on the other hand, have been gulping anti-inflammatories.

These pain relievers, such as aspirin, Advil and Ibuprofen, are all a type of drug called Nonsteroidal Anti-inflammatory Drugs (NSAIDs). They are used regularly by over 50 million people in this country, who spend over $2.7 billion a year on them. Their reputation as pain relievers and anti-inflammatories is well learned. They do the job. But they have a side effect that is rarely mentioned: They inhibit cartilage repair and accelerate cartilage destruction. Since connective tissue damage is caused by degeneration of cartilage, NSAIDs mask the symptoms (pain and swelling) but probably worsen the condition. There is an added risk for athletes. Using NSAIDs before and during exercise has been linked to acute renal failure due to dehydration and stress on the kidneys. Other side effects include gastric ulceration and liver and kidney damage.

One of the natural agents used in Europe with none of these side effects is called glucosamine. Rather than simply mask the symptoms, glucosamine treats the underlying degenerative process affecting the connective tissue. It is safe because glucosamine, a single molecule composed of glucose and an amine (nitrogen and two hydrogen molecules), occurs naturally in the body as a chondro-protective agent. It stimulates the manufacture of glycosaminoglycans, which are key structural components of connective tissue.

Glucosamine also promotes the incorporation of sulfur into the connective tissue. Sulfur is a mineral that functions as an important component of connective tissue. Because of this affect, glucosamine sulfate may be the best source of glucosamine.

As people age or train past a certain point, they lose the ability to manufacture sufficient levels of glucosamine. This results in connective tissue damage and injury. The onset can be subtle. Stiffness could be the first symptom, followed by pain when you move the muscle.

In clinical trials, connective tissue and overall physical performance improved in people taking glucosamine compared to groups taking placebos and Ibuprofin. While Ibuprofin relieves pain faster, glucosamine was more successful overall. Usually it takes four to ten weeks to produce noticeable results. These results and the research behind glucosamine are so impressive that glucosamine has become the front-line therapy against osteoarthritis in Europe There is also evidence that glucosamine is an effective preventative tool. There are other natural herbal analgesics and anti-inflammatories used in Eastern medicine that don't seem to have the negative consequences on connective tissue repair and growth, including white willow bark, ginger, tumeric, boswellia, cuercetin, bromelain and arnica. Recovering properly, then, is a combination of giving the muscles enough time to rest and enough nutrients to replace those you've depleted.. Rest and an optimal diet takes the guesswork out


of the replacement process, and makes it much easier for you to reap the benefits of your training program.

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OPTIMAL TRAINING VS. OVERTRAINING. THEY'RE DIFFERENT

As a society, we are results oriented, demand rapid improvement and are impatient when nothing seems to be happening. As a result, we are less likely to give the recovery period between workouts its due. Since exercise is a stress, however, it is important to realize that the adaptations don't happen during exercise, but during the recovery period, when the body has a chance to cope with the changes. We know that we are sore and tired, but our need for rest may be interpreted as a sign of weakness or backsliding. So rather than take the time off and let our bodies adapt, we all too often push ourselves through another workout in the mistaken belief that we're doing our bodies a favor.

What we are really doing, however, is making the problem worse. Rather than getting the benefits of training, we are courting the dangers of overtraining. Overtraining is measured as a drop in physical performance associated with lethargy, decreased motivation and generalized fatigue. It is an indication that the training stress is in excess of the body's ability to adapt and recover.

Scientists have numerous ways to measure the amount of stress exercise places on the body. Some invasive methods include measures of blood and urine. Non-invasive methods include monitoring body weight changes, motivation, decreases in performance, as well as other parameters. One of the most highly effective and accurate methods which you can use to monitor your own level of training stress and effectiveness of your overall nutritional and recovery program to avoid overtraining is to measure your morning resting heart rate. Start by taking your morning pulse first thing upon waking for seven to ten days. At the end, average the figures to get your average resting pulse. An elevation of as little as 10 percent indicates training stress. A 20 percent increase, particularly lasting more than two days, is indicative of overtraining. Whenever your morning resting pulse is elevated by more than 10 percent, you must reduce your training overload and pay particular attention to yournutritional needs and rest.

If you don't, instead of making you stronger, the physical activity will compromise your immune system. Rushing the recovery process leaves you more vulnerable to low-level infections, aches and pains, and elevates the risk of joint and muscle injuries, due to constant fatigue. Training through both fatigue and/or injuries can even lead to compensation injuries.

These overtraining-related injuries are the most common form of injury in both recreational and elite athletes. Recovery is the key to their prevention. To recover properly, you have to give the muscles sufficient time to recover, restore the depleted nutrients and supply the body with adequate additional nutrients for growth and adaptation. Once you have done that, your body is ready for the next workout and the next round of adaptations.

Overtraining, then, ultimately undermines the workout's effectiveness. In lay terms, exercise tears your body apart so that it can get stronger. For this to happen, the body needs some time to respond. It is during this recovery period, not during the workout itself, that the positive adaptations associated with exercise, such as improved cardiovascular fitness, muscle strength and/or size, and increased flexibility take place.

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BODY COMPOSITION

Looking around the gym, track or office we soon realize that the human physique can be separated by body size, structure and composition. With all the various sizes and shapes, we can still get a good idea of one’s fitness level simply by looking at them. With the growing evidence of the value of regular physical activity on health and fitness, the evaluation of body composition has become both an important and desired aspect for the determination of ones overall fitness. Body composition is generally separated into the two components: fat mass or body fat level, and fat-free mass, generally referred to as lean body mass. 

Many athletic training and health-related fitness programs are designed to control body weight and body composition. This is accomplished through regular exercise and proper nutrition. Being overweight is associated with many medical problems such as diabetes, heart disease and high blood pressure. Appropriate body composition is also important for athletic performance. Excess body fat lowers aerobic fitness and reduces the ability to perform many activities requiring jumping or explosive power. Being too light, lean or thin is not desirable either. Losing excessive bodyweight, which includes lean muscle mass will decrease the athletes effective horsepower and decrease their performance. Suitable body composition is important for general health, appearance, and maximizing athletic performance. For these reasons, accurate measurements of body composition are needed to develop sound preventive health and athletic programs.

By now we are all well aware of the differences between overweight and over fat. A scale does not differentiate body fat (fat mass) from lean bodyweight (fat-free mass). It is possible to be overweight but not over fat (look at most bodybuilders or strength and power athletes) It is also possible to be over fat and yet fall within the normal weight range. By measuring your body composition a more accurate indication of your health and fitness level can be assessed than that achieved using bodyweight alone.

Numerous methods exist for measuring body composition. The names of some sound futuristic, scary or exotic, yet each method basically produces comparable results with similar limitations. The methods described below range from the common, underwater (hydrostatic) weighing, Skinfold calipers and circumference measures to the more exotic, potassium (K) spectroscopy, Bod Pod, total body electrical conductivity (TOBEC), bioelectrical impedance and near infrared reactance. Each method has been validated using comparison measures with the gold standard, that of hydrostatic weighing. Yet as we will shortly see, hydrostatic weighing has some limitations of it’s own. In fact, the only, truly precise method for the determination of your body composition would be to perform an autopsy on your body. Due to the invasive nature and finality of this procedure we are limited to non-invasive, indirect methods. Despite each methods potential errors, it is possible to measure percent body fat within sufficient accuracy to monitor changes in body composition subsequent to exercise training and to screen people for health risks. With carefully used measurement methods, percent body fat can be estimated with an error of approximately 3 to 4 percent. With inappropriate methods and poor measurement technique, prediction errors will be much larger. Monitoring changes in your fat level through test / retest should be your goal whichever method you choose rather than relying on a single test result.

Research into indirect body composition testing began in the 1930s. The research by Behnke and others utilized a simple two-component model of body composition, which, while being reasonably accurate for certain sedentary populations has several limitations for athletic populations (see side bar I). The hydrostatic (underwater) weighing method is the most common laboratory method used to measure body composition. The measurement objective of hydrostatic weighing is to find body volume, which is the used with bodyweight to calculate body density. Percent fat is calculated from body density. The underwater weighing method is based on the Archimedes Principle for measuring the density of an object. When a person is submerged under water, the difference between the weight in air (on land) and under water equals the weight of water displaced. Through several mathematical equations both body density, percent body fat (%BF), and fat-free mass (FFM) are determined. The density of lean tissue (FFM) varies by age, gender, race, athletic conditioning, and bone density, among others. Like all biological components, the FFM may have a variable density value, which is where much of the inaccuracy of this, and other methods lie.

With hydrostatic weighing, body weight, underwater weight, residual lung volume and water density are needed to calculate body density. The underwater weight is greatly dependent on the amount of air in the lungs when the person is submerged. The volume of the body that is air can introduce the largest source of error in the underwater weighting method. The major potential sources of measurement error are 1) the volume of air left in the lungs after expiration (residual volume) and 2) air elsewhere. Trapped air, particularly in the gastrointestinal tract, air bubbles in the hair, bathing cap, or in bathing suit also can introduce error. Residual lung volume is often estimated from height-weight charts or measured indirectly in a lab. For most accurate values, care must be taken that the subject completely exhales while underwater to eliminate potential error. Using predicted residual lung volume rather than measuring it makes the underwater weighing method less accurate, increasing the error 1 to 3.5 percent.

Numerous other indirect laboratory techniques have been developed using hydrostatic weighting as a criterion for accuracy. Each of these techniques are expensive, requiring laboratory equipment generally found at medical or research settings. Several of these are primarily experimental, so their potential for screening of athletes or mass testing of the general public is limited. Some of these techniques are described below.  All but the first two have been used to measure the body composition of selected athletic populations.

In NEUTRON ACTIVATION ANALYSIS, one of the more experimental techniques, a beam of fast neutrons is delivered to the subject. The body becomes temporarily radioactive, and the gamma emissions are recorded in a whole body counter allowing for estimates of various body components and body composition. MRI is also primarily experimental with respect to body composition analysis, although it is widely used in clinical medicine. An external magnetic field applied across a part of the body affects the rotation of the nuclei of atoms in our cells. The body is then exposed to an alternating magnetic field of the same frequency. Measurement of one or more parameters of these nuclei enables the formation of body images. These images are amazingly clear, giving the impression that one is inside the body looking directly at the tissue(s) under observation.

HYDROMETRY involves assessment of the body’s total water content. Isotopic tracers are either ingested or injected and allowed a period of time for equilibration throughout the total body water. Since the absolute volume of the tracer is known and all of the body’s water is in the fat-free mass and generally constitutes from 72-74%, the FFM can be estimated by determining the concentration of the tracer in urine, blood or saliva after the period of equilibration.

SPECTROSCOPY can be used to determine the body’s total potassium (K) content. The subject is placed in a whole body counter, which detects a natural radioisotope of potassium found in our cells, which is emitted as gamma radiation. Fat-free mass is estimated from potassium radiation because the isotopes proportion of the total body potassium remains constant.

RADIOGRAPHY or COMPUTER TOMOGRAPHY  (CT) has been used to determine regional body composition. A CT scanner produces a cross-sectional image of the distribution of x-ray transmission. Use of the CT procedure has become popular in differentiating muscle and internal organs from trunk adipose tissue. This has important health related implications because abdominal, or upper body, obesity is highly correlated with increased risk of coronary artery disease, hypertension and diabetes. These relationships were initially established from simple waist-to-hip ration measurements (covered later). To date, CT technology has not been used to provide estimates of total body fat.

The BOD POD is based on the same principle as underwater weighing. Rather than being dunked into a tank of water, the subject sits inside the POD’s chamber for 20 seconds. During this time computerized pressure sensors determine the amount of air displaced by the person’s body. Form these measures body density is determined and can be used to determine both fat mass and fat-free mass. The obvious advantage is the ease of testing without the use of water. This method is generally more expensive and less available.

The final laboratory technique, TOBEC, is based on the principle that the differences in electrical conductivity properties of fat-free and fat tissues can be used to estimate body composition. The subject is placed inside a large Polaroid coil and a small radio-frequency current is passed through the subject’s body. The electrolytes in the fat-free body mass account for most of the electrical conductivity; thus total body electrical conductivity is highly correlated to the fat-free body mass.

Due to the need for highly trained technicians and expensive laboratory equipment, hydrostatic weighing and these other techniques are most common in clinical, educational and experimental settings. The most common alternative is to use some form of anthropometric method, which include, weight-height ratios, body circumferences and skinfold measurements. Two additional, portable techniques that exist are bioelectric impedance and infrared interactance.

BODY MASS INDEX (BMI) is the weight-height ratio often used in large scale testing. BMI is computed by

 BMI = Weight / Height²

where weight is in kilograms and height is in meters. While BMI is correlated with hydrostatic weighing, the correlations are lower than found with skinfold measurements. BMI is generally not used to determine the degree of obesity, rather to define overweight. A BMI > 27.8 for adult males or > 27.3 for an adult female is considered overweight by the criterion used for the Healthy People 2000 public health program.

BODY CIRCUMFERENCES can be measured at numerous sites on the body, including the waist, gluteal, thigh, biceps and forearm. The circumferences that tend to be most highly correlated to body fat are in the abdominal and hip regions. Waist to hip ratios have been developed to estimate health and overweight risk. When more fat is stored around the waist, a higher waist circumference, an increased risk of heart disease and diabetes exist.

SKINFOLD measures are some of the most popular methods of body composition testing. Skinfold measurements are highly correlated with underwater-determined body density. Skinfold measurements involve measuring a double thickness of subcutaneous fat at several locations throughout the body using a specially designed caliper. The skinfold method is based on the assumptions that the thickness of the subcutaneous fat reflects a constant proportion of the total fat mass and that sited selected for measurement represent the average thickness of the subcutaneous adipose tissue. Accurate estimation of body fat from skin folds depends on selecting a prediction equation and appropriate sites for the individual being assessed. Using an appropriate caliper and measuring accurately the same skinfold site used in the development of the prediction equation are also critical. Additional errors are possible if the measured skinfold sited are not representative of the subject’s fat distribution and if the ratio of internal to external fat is different from the group for which the prediction equation being used was developed. Athletes generally have lower subcutaneous body fat levels than the general population. Weight loss also tends to reduce subcutaneous body fat levels to a greater extent than internal fat levels, thereby reducing the absolute accuracy of this method of testing. The proficiency of the tester is imperative when using the skinfold methods. Measurements of skinfold thicknesses can also be used to track changes in body fat . Carefully measuring a set of skin folds at specific sites at regular intervals can indicate if the thicknesses (subcutaneous body fat levels) are changing.

BIOELECTRICAL IMPEDANCE ANALYSIS (BIA), a portable method similar in technology to TOBEC, is based on the principle that the electrical resistance of the body to a mild electric current is related to total body water. Total body water and fat-free weight are highly related. The BIA method is simple and requires only the placement of four electrodes, two on the ankle and two on the wrist. A current is transmitted into the subject, and the resistance is read directly into a microcomputer that calculates body composition. BIA estimates of percent body fat have an accuracy similar to that of skin folds, except for obese and very lean subjects. Prediction equations developed on the general population tend to underestimate percent body fat of the obese and overestimate the percent body fat of very lean subjects.

NEAR INFRARED REACTANCE is a method based on the principles of light absorption and reflection. A fiber-optic probe is positioned over the belly of the biceps muscle of the arm, and an infrared light beam is emitted. Reflected energy or light absorption is monitored as the light beam penetrates subcutaneous fat and muscle is reflected off the bone and conducted to the probe. More studies are needed to validate this technique for sports participants before it becomes a viable method of testing.

The accuracy for each of these portable methods for estimation of the body composition depends upon the appropriate models (most utilize the two compartment model) and measurement method, skill of the individual performing the measurements, and the use of prediction equations specific to the subjects appropriate gender and age. Appropriate methods and careful measurements make it possible to estimate percent body fat with an error of approximately 3 to 4 percent fat and fat-free mass with an error of 2.0 to 2.5 kg. Table 1 summarizes some of the methods described above.

Competitors in sports such as gymnastics, bodybuilding, dancing, wrestling, and distance running are typically very lean. While the potential advantage of a low percent body fat for success in these sports is evident, there are negative implications for health and performance when weight reduction is carried to extremes. Numerous studies have shown that when an athlete’s body weight drops below a certain critical level, decrements in performance and incidence in injuries and illnesses increases. The minimal levels of percent body fat considered compatible with good health are 5% for males and 12% for females.  The average adult body fat ranges between 15-18% for men and 22-25% for women. The levels found in elite athletes vary considerably from sports to sport (see side bar II).

Ours is a society of comparisons.  We constantly strive to increase our wealth, position, appearance, and the list goes on by comparing ourselves with those around us. When using a selected method for determining which method to choose for determining body composition, it is important to remember the limitations involved within each method and weigh the costs with the benefits. Just like the bathroom scale, each method should be used as a relative gauge to monitor your progress throughout a weight loss or training period, rather than with comparisons to some arbitrary, often unattainable goal. Health and performance should be the ultimate goal and optimal bodyweight and compositions are not necessarily restrictively low. 

Side bar I:

INDIRECT ASSESSMENT

HISTORY & LIMITATIONS

The research by Behnke and others proposed a simple two-compartment model of body composition: fat mass and fat-free mass (FFM). Fat-free body mass includes protein, carbohydrate, mineral, and water. Several laboratory techniques are now available to assess body composition based on the original two-compartment model. Densitometry, first developed by Behnke, and commonly known as hydrostatic (underwater) weighing has been the most widely used and is generally considered the criterion technique against which all other techniques are validated. The measurement objective of the hydrostatic weighing is to find body volume, which is then used with body weight to calculate body density. Percent fat is calculated from body density.

The major limitation of the two-compartment model, and therefore hydrostatic weighing, for body fat determination is that the chemical composition of the FFM is not constant. In particular, water content and mineral (bone) content can vary considerably from the norm used in the prediction equations. Long-term specialized training such as regular resistance exercise may alter FFM composition by increasing muscle and bone mass. Conversely, in some sports, competitors may have less than average muscle and bone mass. Deviations from the assumed chemical composition of the FFM result in under- and over-estimation of body fat by hydrostatic weighing, depending on whether the density of FFM is greater or less than the assumed density used in the initial research studies. Thus, % BF may be overestimated in individuals with lower than average bone mass and underestimated in individuals with greater than average bone mass. These errors in the densitometry criterion method for fat estimation are then passed on to other BF testing methods, which are validated against this criterion method.

Multiple component models have been developed to help eliminate some of these potential errors. These methods also attempt to measure body water and bone density independently. Although more accurate than the two-component model, there has been no systematic attempt to define water and mineral fractions of FFM in different groups of athletes or different groups within the population. The body is composed of approximately 60-70 percent water and the level can vary considerably from day to day and from pre- to post-exercise, thereby effecting the validity of each method used for BF determination.  As yet, the limitations must be minimized by utilizing the same method for test / retest and make sure testing is done under as similar conditions as possible (including time of day, hydration level, technician, procedure, etc.).

Side bar II:

OPTIMAL BODY COMPOSITION

The percent body fat level for elite athletes varies from sport to sport. Although levels of percent body fat (%BF) are related to successful performance within a sport, athletic performance cannot be accurately predicted solely on the basis of body composition. Fat-free mass is better correlated than %BF with successful performance of physical tasks requiring the ability to push, carry and exert force. On the other hand %BF is inversely related to maximal aerobic capacity and to distance running performance. Below is a list of ranges seen for several sports. The ranges seen with many sports are often higher than expected and higher than the minimal safe level.

 

 

It must be emphasized that there is not a precise relationship between body fat level and athletic performance. When male athletes go below eight to ten percent and female athletes go below fourteen to sixteen percent body fat, there is little, if any, scientifically verifiable evidence of further improvement in performance.

  

 

T ABLE 1: COMPARISON OF EVALUATION METHODS

METHOD	STRENGTH	LIMITATION	ACCURACY - % FAT
Hydrostatic (two -component model)	Accurate with mature adults	Need expensive equipment; must measure residual lung volume	1% fat, > 3% if residual volume not measured
Hydrostatic (multi-component model)	Most accurate indirect method; can be used for all age groups	Expensive; few labs have capacity to measure body water and mineral content; must measure residual volume	1% fat, > 3% if residual volume not measured
Skinfold method	Inexpensive; feasible for large groups; appropriate for most adults	Tester errors measuring skin folds; does not measure internal fat; developed with two-compartment model, population specific equations for estimates	3.5% - 4.0% fat
Bioelectrical Impedance (BIA)	Just need to attach four electrodes; feasible for large groups; potential method to measure body water	Validated on two-compartment model; lack accuracy with very lean and obese; expensive equipment, testing errors	3.5 to 4.0% fat
Body Circumferences	Very inexpensive; feasible for group testing	Errors measuring circumferences; does not measure internal fat, developed on two-compartment model	3.7 to 4.5% fat
Body Mass Index (BMI)	Most feasible (need only height and weight), overweight standards are defined	Does not differentiate between fat and fat-free weight; does not estimate % fat; least accurate	> 4.5% fat

 

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