Abstract
Nutrition and health educators work in community settings implementing lifestyle programs focused on obesity prevention and chronic disease risk reduction. These programs typically focus on improving diet and physical activity (PA) behaviors. Many nutrition educators may not be confident in their ability to select, administer, and interpret PA assessments to effectively evaluate their PA or lifestyle programs. This report will assist educators in identifying and selecting appropriate field-based assessments for measurement of PA, physical fitness, and body composition for children and adults. Specific guidelines, references, and resources are given for selecting assessment methods and test within these 3 areas.
Key Words
Introduction
There is strong scientific evidence that physical activity (PA) increases health-related fitness and decreases risk for chronic and disabling diseases, including obesity, in active compared with inactive adults.
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To achieve these benefits, adults need to participate in 150 min/wk of moderate or 75 min/wk of vigorous PA. For youth and children ages 6 years and older, there is also strong scientific evidence that PA substantially improves cardiorespiratory fitness, strengthens bones and muscles, helps to attain and maintain healthy weight, reduces risk of depression and anxiety, and decreases the likelihood of developing risk factors associated with chronic disease.2
To achieve these benefits children and youth need to participate in 60 min/d or more of PA,1
including aerobic and age-appropriate muscle and bone-strengthening activities.2
In addition, the 2010 Dietary Guidelines for Americans3
support engaging in PA to assist in balancing energy expenditure with energy intake for the maintenance of a healthy body weight and reduction of chronic disease.Health and nutrition educators work in community settings implementing healthy lifestyle programs focused on obesity prevention and chronic disease reduction. These lifestyle programs typically emphasize improving diet and PA behaviors, which will result in improvements in health outcomes such as body size and fitness, or reduced chronic disease risk factors. To determine the effectiveness of these programs, nutrition educators must identify and measure outcomes related to their program goals. As part of the overall lifestyle program evaluation, assessing changes in diet, PA, or physical fitness (PF) is frequently done. Although nutrition educators are confident in their ability to assess dietary change, they may be less confident in their ability to select, administer, and interpret PA or PF assessments to measure the impact of a PA intervention. The goal of this report is to help nutrition educators, who are less familiar with exercise science, to identify and select appropriate field-based assessment tools for the measurement of change in PA, PF, and/or body composition. First, definitions of the PA and exercise science terms used within this report are given. Second, field assessments of PA and PF are given based on the measures each method or test provides, the audience for which they were designed and validated, the length of the assessment, the method description, and the advantages and disadvantages of the method. Within each of these areas, the method or test that would work best within a community-based setting with limited training and costs is identified. Third, field assessment measures of body composition are briefly addressed. Emphasis is placed on helping the educator identify the method or test that will work best in the field, based on the skills, time, and resources of the educator, the environment in which they are working, and the population they are evaluating.
Definitions
To understand the assessment measures of the PA and PF methods in this report, it is important to understand the meaning of the terms used. Physical activity refers to the body movement that enhances health and increases energy expenditure; PF is the capacity to perform PA based on various physiological indicators. An individual can be physically active and not physically fit, or have some increased measure of fitness and not be active. Other exercise science and PA terms used within this report are defined in Table 1.
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Table 1Terms and Definitions Used to Describe Physical Activity and Exercise
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| Terms | Definitions |
|---|---|
| PA | Any body movement that enhances health and increases energy expenditure above basal levels |
| PF | Capacity to perform PA based on various physiological parameters. One can be physically active and not physically fit, or have some increases measure of fitness and not be active |
| Exercise | A subcategory of PA identified as planned, structured, and purposeful, designed for improvement or maintenance of PF (eg, sports, jogging, swimming, physical education classes). Exercise is sometimes referred to as programmed PA |
| ADL | Activities required for everyday living, including eating, walking, standing, cooking, dressing, getting up from chair, and activities associated with one's job, work, or school. There is clear research evidence that all PA, including ADL and planned exercise, can contribute to overall health, especially maintenance of healthy body weight and weight loss, or maintenance of weight loss after dieting |
| Duration | Length of time in which an activity or exercise is performed and is reported as minutes per day or week. |
| Frequency | Number of times an activity or exercise is performed and is reported as number of sessions or bouts per day or week |
| Intensity | Work that is being performed or magnitude of effort required to perform and activity or exercise, expressed in absolute or relative terms |
| Absolute intensity | Amount of work being performed, not taking into account physiological capacity of individual. Absolute intensity is reported as energy expenditure required per kilogram body weight per minute or amount of oxygen used by the body doing the activity, expressed using an MET level (eg, 1 MET at rest; 7 METs while running quickly). Absolute intensity is sometimes expressed as the speed in which an activity is performed (eg, walking at 3 mph) |
| Relative intensity | An individual's exercise capacity (eg, how PF they are). For aerobic activity, relative intensity is expressed as a percentage of an individual's total aerobic capacity, measured or estimated heart rate. |
| Sedentary behavior | A new measure of activity being assessed by some researchers, defined as the amount of inactivity an individual engages in each day (eg, sitting or lying down; typically 1–1.5 times the resting metabolic rate 37 ). Sedentary behavior can be measured in 3 ways: time (minutes per day in inactivity), type (eg, TV or screen viewing, reading, sitting, motorized transport), and frequency (length [minutes per bout] and frequency [bouts per day] of sedentary behavior). Television viewing is the most frequently surveyed type of sedentary behavior in children.38 , 39 The Youth Risk Behavior Survey designates ≥ 3 h/d of TV viewing as excessive, whereas the National Health and Nutrition Examination Survey 2001–2006 reports ≥ 2 h/d as excessive. When using accelerometers to define sedentary behavior, several cutoff points (< 100 to < 1,100 counts/min) have been applied to sedentary behavior40 |
| Body composition | Health-related component of PF that applies to body weight and relative amounts of muscle, fat, bone, and other vital tissues of the body. Most often, the components are limited to fat and lean body mass (or fat-free mass) and expressed as relative (percentage) and absolute (kilograms) |
| Body size | Measured height (centimeters) and weight (kilograms); can be used to determine BMI (kilograms per square meter), a proxy measure for body fat. Body composition and size are frequently used as outcome measures to determine whether improvements in diet and PA are effective in weight management or obesity prevention |
| Aerobic capacity | Body's capacity to transport and use oxygen during maximal exertion involving dynamic contraction of large muscle groups, such as during running and cycling |
| Muscular strength | Health and performance component of physical fitness: ability of a muscle or muscle group to exert force |
| Muscular endurance | Health-related component of PF that applies to ability to produce force or torque repeatedly against submaximal external resistances |
| Flexibility | Health- and performance-related component of physical fitness: range of motion possible at a joint |
| MET | 1 MET is the rate of energy expenditure while sitting at rest. It is taken by convention to be an oxygen uptake of 3.5 mL/kg body weight/min. Physical activities frequently are classified by their intensity using MET as a reference |
ADL indicates activities of daily living; BMI, body mass index; MET, metabolic equivalent; PA, physical activity; PF, physical fitness; TV, television.
Physical Activity Assessment
Ideally, PA assessment should measure all dimensions of PA, including type, frequency, intensity, and duration. However, there are times when measuring only 1 or 2 dimensions of PA will be required or necessary. No single method provides a comprehensive assessment of PA;
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thus, a combination of methods may be required to obtain the desired outcomes. Physical activity assessment methods can be divided into 2 general categories: (1) indirect measures using questionnaires, PA logs, or proxy reports (Table 2); or (2) direct measures using motion sensors (eg, accelerometers, pedometers, heart rate [HR] monitors) or observation (Table 3). The key factors that determine which method to select depend on the PA assessment measure that best evaluates the program (eg, minutes per week of PA, level or type of PA) and audience (age, skill in reading/writing or recall), while minimizing participant burden (time required) and cost and resources required to administer the assessment. The goal is to select a method that provides appropriate data to address program objectives with the least amount of time, effort, and money.Table 2Indirect Methods for Measuring PA
| Measure | Method, Audience, and Time Frame | Description | Strengths | Weaknesses |
|---|---|---|---|---|
| Categorical PA score (low, moderate, or high PA) or continuous (MET [minutes per week]) | IPAQ 41 , International Physical Activity Questionaire. IPAQ Group. https://sites.google.com/site/theipaq/home. Accessed March 11, 2013. 42 Audience: Adults, 15–69 y Time: Previous 7 d of activity IPAQ-SF 43 Audience: Adults, 15–69 y Time: Previous 7 d of activity |
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| Categorical PA score based on 5-point scale, with 5 being highest PA | PAQ-A 45 , Kowalski KC, Crocker PRE, Donen RM. Physical Activity Questionnaire for Adolescents. http://www.performwell.org/index.php/find-surveyassessments/outcomes/health-a-safety/good-health-habits/physical-activity-questionnaire-for-adolescents. Accessed March 11, 2013. 46 Audience: 14-18 y Time: Previous 7 d of activity PAQ-C 42 , 47 Kowalski KC, Crocker PRE, Donen RM. Physical Activity Questionnaire for Children. http://www.performwell.org/index.php/find-surveyassessments/outcomes/health-a-safety/good-health-habits/physical-activity-questionnaire-for-children. Accessed March 11, 2013. Audience: 6-13y Time: Previous 7 d of activity |
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| Total minutes PA per day; PA type, intensity, frequency, and duration | PDPAR and 3DPAR Audience: Adults or children Time: Previous day or 3 d of activity PA diaries or log Audience: Adults or children Time: ≥ 1 d |
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| PA proxy reports 53 Audience: Preschool children (< 10 y) or people with limited cognitive recall Time: ≥ 1 d |
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3DPAR indicates 3-day PA recall; EE, energy expenditure; IPAQ, International PA Questionnaire; IPAQ-SF, IPAQ Short Form; MVPA, moderate (3–5 METs) to vigorous (> 6 METs) physical activity; PA, physical activity; PAQ-A, PA Questionnaire for Adolescents; PAQ-C, PA Questionnaire for Children; PDPAR, previous day PA recall; other abbreviations as in Table 1.
Note: One MET is the rate of energy expenditure while sitting; physical activities are classified by their intensity or MET level (eg, fast running = 7 METs. For IPAQs, MET minutes per week = MET level × minutes of activity × events per week.
Table 3Methods for Direct Measurement of PA
| Measures | Method, Audience, and Time Frame | Description | Strengths | Weaknesses |
|---|---|---|---|---|
| Total PA (minutes per day session); PA type, duration, and intensity | Observation Audience: Adults, children (< 10 y) or people with limited cognitive recall Time: ≥ 1 d |
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| Primary: Movement counts Secondary: PA frequency, duration, and intensity | Accelerometer Audience: Adults or children (> 3 y) Time: Multiple days (≥ 4 d) |
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| Number of walking steps per day or session | Pedometers Audience: Adults or children Time: Multiple days (1–7 d) |
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| Time HR above designated cut points; PA frequency, duration, and intensity | HR monitor Audience: Adults or children Time: Multiple days (1–7 d) |
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| Distance traveled, time stamp, PA duration and movement speed | Global positioning system monitoring unit Audience: Adults or children Time: Multiple days (1–7 d) |
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EE indicates energy expenditure; HR, heart rate; MVPA, moderate (3-5 metabolic equivalents) to vigorous (> 6 metabolic equivalents) physical activity; PA, physical activity.
Indirect Measures of PA
These are the most widely used field assessment methods because they are validated, simple to use, and low in cost. Table 2 lists indirect PA outcome measures along with the method description, strengths and weaknesses of the method, the audience for which the method can be used, and the time period over which PA is being assessed. This table can be used to match PA outcome measures with assessment needs.
Direct Measures of PA
These methods provide real-time estimates of the frequency, intensity, and duration of free-living PA; however, they are more labor- and cost-intensive, and thus less frequently used in field settings. Table 3 lists direct PA measures categorized into 2 areas: (1) motion sensors and monitors (ie, accelerometers, pedometers, HR monitors); and (2) direct observation (eg, watching and recording playground use during school recess) (see Supplementary Data). These measures are best suited for small-scale research studies in which cost, participant burden, and specialized staff training can be better accommodated. However, these measures are useful for children, because they require no self-reports of PA, which can be difficult for children or parents to perform with accuracy.
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Methods can be combined, sometimes within 1 device, to provide multiple data points for the overall assessment of PA. For example, an accelerometer combined with an HR monitor will measure both volume (steps) and intensity (HR) of PA. Global positioning system mapping technology is currently being added to better understand PA and movement patterns of children and adults.6
As the cost decreases and ease of use increases, these devices will become more practical for field-based use.Physical Fitness Assessment
Physical fitness is typically assessed by challenging 1 or more health components (muscular strength, muscular endurance, cardiovascular endurance, and flexibility). To select the right PF assessment test, it is important to consider portability and cost (eg, field-based step tests or walking tests vs a graded exercise treadmill or bicycle protocol used in laboratories), validity and reliability (eg, choice and execution of specific protocol standards), test evaluation criteria (eg, cutoff criteria for levels of fitness vs normative reference standards), and the population being tested (eg, adults or children).
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Although field-based tests are not as precise as laboratory tests, they provide a simple cost- and time-effective measurement of PF without expensive and technical equipment. They also allow for many participants to be tested simultaneously by research technicians with little training, and thus are the focus of this section.Validity and Reliability
Physical fitness tests need to measure the desired changes in intervention behaviors associated with fitness outcomes; thus, test validity and reliability are critical. Test validity measures whether the test is accurately measuring what it purports to measure. Test reliability is the degree to which a test can be consistently repeated each time the test is used under the same conditions, with a clear test protocol and user training. It is essential to select a PF test that has concise methodology for repeatability of a score within the testing conditions and environment (eg, using the correct angle of bent knees for a sit-up test). Adherence to the protocol will ensure confidence in the results and the changes measured as the result of implementing a program or intervention.
Evaluation Criteria
Knowing the assessment scores or cutoffs associated with a participant's PF is essential to test selection. Cutoffs are based on criterion-referenced (CR) standards or normative data.
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Criterion-referenced standards are frequently linked to indicators of health outcomes or health risk factors. Normative data are based on past performance of a representative group (eg, percentile rankings) and are effective for measuring pre/post-intervention results and motivating participants by using their personal improvements, but do not provide comparisons related to health outcomes or risk factor reduction. However, these tests must include a substantial database size, such as the YMCA Adult Fitness Battery, which has approximately 70,000 subjects in its database.7
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Selecting a PF Test
When selecting a field-based PF test, the assumptions of the assessment tool need to match the population being tested and outcome measures selected. The 4 areas of PF measured include cardiovascular fitness, muscular strength (maximum strength), muscular endurance (strength over time), and flexibility. Some adult comprehensive tests include all areas of PF and can be adopted in their entirety; however, options to select single test items are also available (see Table 4 for adult fitness tests). References are provided for more in-depth explanation of the tests.
Table 4Adult Fitness Tests
| Outcome (Measure) | Test | Test Length | Equipment | Description |
|---|---|---|---|---|
| Adult fitness tests 65 Adult fitness test. President's Council on Fitness, Sports & Nutrition. http://www.adultfitnesstest.org/. Accessed March 11, 2013. Aerobic capacity (recorded time) Aerobic capacity (recorded distance) Aerobic capacity (recorded post HR) Aerobic capacity (recorded post-HR) Muscular strength (pushups) Muscular endurance (sit-ups) Flexibility (recorded inches) | 1-mile walk/run (outdoors) 12-min walk/run tests (outdoors) YMCA 3-ft step test (indoors) Queens College step test (indoors) Pushup test Half sit-up test YMCA sit and reach test | 5–15 min 12 min 3 min 3–4 min < 3 min 1 min < 1 min | 1-mile marked area; stopwatch 1-mile marked area; stopwatch 12-in step bench; stopwatch; metronome 16.25-in step bench; stopwatch; metronome Metronome; mat Marked mat Yardstick; tape | Measure amount of time it takes to complete 1 mile Measure distance covered after 12 min running and/or walking Step up and down for 3 min to metronome set at 96 bpm (24 steps/min) measure post-HR for 1 min Step up and down for 3 min to metronome set at 96 bpm for men/88 bpm for women; measure post-HR for 15 s From “up” pushup position, perform pushups to metronome until failure Using mat with marked tape, raise shoulders and reach forward, touching mark as many times as possible in 1 min From seated position, legs straddled, fold forward and reach as far as possible, sliding fingers on yardstick |
| Children's (5–18 y) fitness tests 15 , The President's Council on Fitness, Sports & Nutrition. Presidential Youth Fitness Program. http://www.presidentialyouthfitnessprogram.org/. Accessed March 11, 2013. Aerobic capacity (recorded time) Aerobic capacity (recorded time; post-HR) Aerobic capacity/agility/speed (recorded time) Muscular strength (pushups) Muscular endurance (curl-ups) Flexibility (recorded inches) | 1-mile run 1-mile walk 20-m PACER 90° pushup Curl-up Back saver sit and reach | 5–15 min 5–15 min 5–15 min < 3 min < 3 min < 3 min | 1-mile marked area; stopwatch 1-mile marked area; stopwatch 20-m running lane, pacer CD; CD player Metronome Metronome 12-in sturdy wooden box, tape | Run mile as fast as possible; walk if needed Walk mile as fast as possible, post 1-min HR Run back and forth across 20-m space (or 15-m if preferred) at pace that gets faster each minute Complete as many as possible at cadence of 1 every 3 s Complete as many as possible (up to 75) at cadence of 1 every 3 s One leg straight, 1 leg bent, reaching as far as possible with 1 arm at a time |
HR indicates heart rate; YMCA, Young Men's Christian Association.
a Aerobic tests were recommended for participation in age 5–9 years, but no standards were provided
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The President's Council on Fitness, Sports & Nutrition. Presidential Youth Fitness Program. http://www.presidentialyouthfitnessprogram.org/. Accessed March 11, 2013.
b 1 mile = 1.6 kilometers (km). 1 inch = 2.54 centimeters (cm). A 3-ft step = 91.4 cm. A 12-in step = 28.8 cm. 1 meter (m) = 100 cm or 39.4 inches
c PACER (Progressive Aerobic Cardiovascular Endurance Run) is the aerobic capacity test used in Fitnessgram.
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PF Tests for Children
For children (kindergarten through 12th grade), the most frequently used field PF tests are the CR Fitnessgram
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and the norm-referenced President's Council on Fitness, Sports, and Nutrition, President's Challenge Program.9
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Unfortunately, norm-referenced standards (such as the latter) are difficult to update and focus on performance rather than health, thus rewarding children who are already fit and discouraging those who are not. For some, PF evaluations can be perceived as punishment.14
In an effort to move from norm-referenced standards, the President's Council on Fitness, Sports, and Nutrition partnered with the Cooper Institute and Fitnessgram to develop and promote the Presidential Youth Fitness Program.15
This no-cost program gives the user access to the CR Fitnessgram standards, including training and resources for assessing and tracking Web-based support, test protocols, and aerobic capacity and body mass index (BMI) (kg/m2) calculators. Results are gender and age specific. These tests require minimal equipment and training, are low cost, and are CR and field-based (Table 4).The President's Council on Fitness, Sports & Nutrition. Presidential Youth Fitness Program. http://www.presidentialyouthfitnessprogram.org/. Accessed March 11, 2013.
Although participation in these PF tests is also encouraged for young children (ages 3–5 years), there are no reference points on most tests because no standard has been set for this age group. Furthermore, PF is not generally measured in young children. Nevertheless, assessing physical movement skills is important. Motor development is positively related to PA activity,
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and children in primary grades who are proficient in motor skills are more likely to engage in vigorous PA as adolescents.8
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Because PA, specifically step counts, declines after age 6 years, measurement may be critical in preschoolers.18
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Although there are a number of tests for gross motor development (GMD), there are few simple and inexpensive field-based tests for measuring skill changes in young children. Gross motor development tests, which primarily focus on developmental motor skills, impairment, and developmental delays, are costly and require sophisticated training, equipment, and skilled therapists. Alternatively, the Test for GMD-2 (TGMD-2) is a widely used practical GMD test that requires less training., 23
Primary limitations of this test are that it focuses on object control and requires equipment and an outdoor area for testing.Body Composition
Body composition is frequently used as an outcome measure to determine the effectiveness of community-based obesity prevention strategies. This section briefly focuses on simple field-based methods for assessing body composition, including the advantages and disadvantages of each method based on the population being assessed (Table 5). All field methods for body composition are validated based on a CR method, such as dual-energy X-ray absorptiometry or computed tomography.
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Table 5Field-based Body Composition Assessment Methods
| Measure | Method and Audience | Description | Strengths | Weaknesses |
|---|---|---|---|---|
| Proxy measure for body fat; national cut points based on BMI-for-age. Children and young adults (2–20 y) BMI cut points based on growth charts | BMI (kg/m2) Audience: Adults and children |
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| Proxy measure for intra-abdominal fat | WC (in) Audience: Adults and children |
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| Estimation of FFM and total body water; % body fat and fat mass determined from these estimates | BIA Audience: Adults and children |
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BIA indicates bioelectrical impedance analysis; BMI, body mass index; FFM, fat-free mass; WC, waist circumference.
Body Mass Index
Body mass index (kg/m2) is 1 of the most frequently used field assessments of body size because it is simple and low-cost, and there are national cut points for defining overweight and obesity.
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Overweight refers to weight in excess of standards, whereas obesity refers to excess body fat.24
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For United States (US) children (2–20 years of age), the definitions of overweight (85th to 95th percentile) and obese (≥95th percentile) are based on the Centers for Disease Control and Prevention 2000 gender-specific BMI-for-age growth charts.24
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For children < 2 years of age, a BMI ≥ 97.7th percentile is considered a high weight-for-recumbent length; there is no obesity classification for children this young.24
In adults, regardless of age or sex, overweight is defined as a BMI between > 25 and ≤ 29.9 kg/m2, and obesity as a BMI ≥ 30 kg/m.2
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Waist Circumference
A waist circumference (WC) measurement provides a surrogate estimation of intra-abdominal fat (fat located inside the peritoneal cavity).
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Studies show that excess intra-abdominal fat in adults and children is closely linked with increased risk of adverse health outcomes, including heart disease, dyslipidemia, hypertension, insulin resistance, metabolic syndrome, and type 2 diabetes.29
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Thus, WC is used to predict health risks and determine whether interventions improve chronic disease risk factors.29
Unfortunately, no universally accepted WC anatomical site most effectively identifies health risks (Table 5).29
The 2 most commonly used sites are measured immediately above the iliac crest or the narrowest point between the lowest rib and the iliac crest.29
The cut point used for assessment will depend on the exact anatomical site used to measure WC. In the US, the WC cut points associated with increased chronic disease risk for adults are > 40 in for men and > 35 in for nonpregnant women.29
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These cut points are based on measuring WC immediately above the iliac crest.Defining overweight and obesity. Centers for Disease Control and Prevention. http://www.cdc.gov/obesity/adult/defining.html. Accessed March 11, 2013.
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For children and adolescents, percentiles are used to determine increased risk, but there are no universally accepted WC cutoff values. Research shows that ethnicity can affect the amount of body fat reflected in a certain WC or BMI measurement;29
thus, standardized cut points should be used with caution in ethnic groups. It is now recommended that WC replace the measurement of waist-to-hip ratio.29
Bioelectrical Impedance Analysis
Bioelectrical impedance analysis (BIA) is a quick, portable, and noninvasive method for body fat assessment. This method is based on the relationship between the volume of a conductor (ie, the body), the conductor's length (ie, an individual's height), and the impedance (ie, the resistance of body tissues to the flow of a low-level electrical current).
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Using this principle, BIA can estimate fat-free mass and body fat using prediction equations.20
The prediction equation selected should closely match a subject's characteristics (eg, age, gender, body size, health condition).20
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Validated BIA equations are published for all age groups, but the accuracy of BIA to estimate adiposity, especially in infants, elderly, and those with extreme BMI values, is still debated.23
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Implications for Research and Practice
Nutrition and health educators rely on valid and reliable measurements to assess their community-based programs for effectiveness, areas for enhancement, and data to support sustainability. This overview provides a guide for selecting field-based evaluation tools to estimate PA and PF and measure changes in body composition. In addition, standardizing PA program evaluation measurement techniques allows for comparison between intervention programs and over time.
Acknowledgments
This report is part of work done by the US Department of Agriculture–W1005 Multistate Research Group, entitled “An integrated approach to prevention of obesity in high risk families.”
Supplementary Data
- Appendix 1
References
- 2008 Physical Activity Guidelines for Americans: Be Active, Healthy, and Happy!.US Dept of Health and Human Services, Washington, DC2008
- Physical Activity Guidelines for Americans Mid-course Preport: Strategies to Increase Physical Activity Among Youth.US Dept of Health and Human Services, Washington, DC2012
- Dietary Guidelines for Americans, 2010.US Dept of Health and Human Services, Washington, DC2010
- Assessment of physical activity by self-report: status, limitations, and future directions.Res Q Exerc Sport. 2000; 71: S1-S14
- The youth physical activity promotion model: a conceptual bridge between theory and practice.Quest. 1999; 51: 5-23
- Prediction of activity mode with global positioning system and accelerometer data.Med Sci Sports Exerc. 2008; 40: 972-978
- YMCA Fitness Testing and Assessment Manual. 4th ed. Human Kinetics, Champaign, IL2000
- Welk G.J. Physical Activity Assessments for Health-related Research. Human Kinetics, Champaign, IL2002
- The President's Challenge Is a Program of the President's Council on Fitness, Sports & Nutrition.US Dept of Health and Human Service, Bloomington, IN2012
- Meredith M.D. Welk G.J. Fitnessgram & Activitygram: Test Administration Manual. 4th ed. Human Kinetics, Champaign, IL2010
- Field evaluation of the new FITNESSGRAM® criterion-referenced standards.Am J Prev Med. 2011; 41: S131-S142
- Advanced Fitness Assessment and Exercise Prescription.6th ed. Human Kinetics, Champaign, IL2010
- Relationship of physical activity to fundamental movement skills among adolescents.Med Sci Sports Exerc. 2001; 33: 1899-1904
- Percent body fat and chronic disease risk factors in U.S. children and youth.Am J Prev Med. 2011; 41: S77-S86
The President's Council on Fitness, Sports & Nutrition. Presidential Youth Fitness Program. http://www.presidentialyouthfitnessprogram.org/. Accessed March 11, 2013.
- Childhood motor skill proficiency as a predictor of adolescent physical activity.J Adolesc Health. 2009; 44: 252-259
- The relationship between motor proficiency and physical activity in children.Pediatrics. 2006; 118: 1758-1765
- Accelerometer-determined steps per day in US children and youth.Med Sci Sports Exerc. 2010; 42: 2244-2250
- Test of Gross Motor Development.2nd ed. PRO-ED, Austin, TX2000
- Human Body Composition.2nd ed. Human Kinetics, Champaign, IL2005
- ACSM's Guidelines for Exercise Testing and Prescription.8th ed. Lippincott Williams & Wilkins, Philadelphia, PA2010
- Selected body composition methods can be used in field studies.J Nutrition. 2001; 131: 1589S-1595S
- A new BIA equation estimating the body composition of young children.Obesity. 2011; 19: 1813-1817
- Changes in terminology for childhood overweight and obesity.Natl Health Stat Reports. 2010; 25: 1-5
- Expert committee recommendations regarding the prevention, assessment, and treatment of child and adolescent overweight and obesity: summary report.Pediatrics. 2007; 120: 164-192
- 2000 CDC growth charts for the United States: methods and development.Vital Health Stat 11. 2002; 246: 1-190
- Prevalence of obesity and trends in body mass index among US children and adolescents, 1999-2010.J Am Med Assoc. 2012; 307: 483-490
- Prevalence of overweight, obesity and extreme obesity among adults: United States, trends 1960-1962 through 2007-2008.NCHS Health Stat. June, 2010;
- Waist Circumference and Waist–Hip Ratio: Report of a WHO Expert Consultation, Geneva, 8-11 December 2008.World Health Organization, Geneva, Switzerland2011
- Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: the Evidence Report.National Institutes of Health, Bethesda, MD1998
- Waist circumference for the screening of the metabolic syndrome in children.Acta Paediatr. 2002; 91: 1307-1312
Defining overweight and obesity. Centers for Disease Control and Prevention. http://www.cdc.gov/obesity/adult/defining.html. Accessed March 11, 2013.
- Bioelectrical impedance analysis—part I: review of principles and methods.Clin Nutr. 2004; 23: 1226-1243
- Laboratory and field measurements of body composition.Public Health Nutr. 2005; 8: 1108-1122
- Regional obesity and risk of cardiovascular disease: the Framingham study.J Clin Epidemiol. 1991; 44: 183-190
- Comparison of body fatness measurements by BMI and skinfolds vs dual energy X-ray absorptiometry and their relation to cardiovascular risk factors in adolescents.Int J Obes Relat Metab Disord. 2005; 29: 1346-1352
- Too much sitting: The population health science of sedentary behavior.Exerc Sport Sci Rev. 2010; 38: 105-113
- Systematic review of sedentary behaviour and health indicators in school-aged children and youth.Int J Behav Nutr Phys Act. 2011; 8: 98
- Decrease in television viewing predicts lower body mass index at 1-year follow-up in adolescents, but not adults.J Nutr Educ Behav. 2012; 44: 415-422
- Amount of time spent in sedentary behaviors in the United States, 2003–2004.Am J Epidemiol. 2008; 167: 875-881
International Physical Activity Questionaire. IPAQ Group. https://sites.google.com/site/theipaq/home. Accessed March 11, 2013.
- Validation of the physical activity questionnaire for older children.Pediatr Exerc Sci. 1997; 9: 174-186
- Validity of the international physical activity questionnaire short form (IPAQ-SF): a systematic review.Int J Behav Nutr Phys Act. 2011; 8: 115
- International Physical Activity Questionnaire: 12-country reliability and validity.Med Sci Sports Exerc. 2003; 35: 1381-1395
Kowalski KC, Crocker PRE, Donen RM. Physical Activity Questionnaire for Adolescents. http://www.performwell.org/index.php/find-surveyassessments/outcomes/health-a-safety/good-health-habits/physical-activity-questionnaire-for-adolescents. Accessed March 11, 2013.
- Convergent validity of the Physical Activity Questionnaire for Adolescents.Pediatr Exerc Sci. 1997; 9: 342-352
Kowalski KC, Crocker PRE, Donen RM. Physical Activity Questionnaire for Children. http://www.performwell.org/index.php/find-surveyassessments/outcomes/health-a-safety/good-health-habits/physical-activity-questionnaire-for-children. Accessed March 11, 2013.
- Validation of an instrument for measurement of physical activity in youth.Med Sci Sports Exerc. 1997; 29: 138-143
- Validity and reliability of the 3-day physical activity recall in Singaporean adolescents.Res Q Exerc Sport. 2005; 76: 101-106
- Physical activity assessment in children and adolescents.Sports Med. 2001; 31: 439-454
- Evaluation of the Kaiser Physical Activity Survey in women.Med Sci Sports Exerc. 2000; 32: 1327-1338
- Physical activity questionnaires for youth: a systematic review of measurement properties.Sports Med. 2010; 40: 539-563
- A pilot study using an accelerometer to evaluate a caregiver's interpretation of an infant or toddler's activity level as recorded in a time activity diary.Res Q Exerc Sport. 2007; 78: 375-383
- Observational measures of children's physical activity.J Sch Health. 1991; 61: 224-227
- Objective measurement of physical activity in youth: current issues, future directions.Exerc Sport Sci Rev. 2001; 29: 32-36
- Technical variability of the GT3X accelerometer.Med Eng Physics. 2012; 34: 787-790
- A comparative evaluation of three accelerometry-based physical activity monitors.Med Sci Sports Exerc. 2000; 32: S489-S497
Umstattd Meyer MR, Baller SL, Mitchell SM, Trost SG. Comparison of three accelerometer data reduction approaches, step counts, and two self-report measures for estimating physical activity in free-living adults. J Phys Act Health. In press.
- Effect of BMI on prediction of accelerometry-based energy expenditure in youth.Med Sci Sports Exerc. 2012; 44: 2428-2435
- Comparison of pedometer and accelerometer measures of free-living physical activity.Med Sci Sports Exerc. 2002; 34: 2045-2051
- Assessing pedometer accuracy while walking, skipping, galloping, sliding, and hopping.J Strength Cond Res. 2008; 22: 276-282
- Estimating energy expenditure by heart-rate monitoring without individual calibration.Med Sci Sports Exerc. 2001; 33: 939-945
- Utility of global positioning system to measure active transport in urban areas.Med Sci Sports Exerc. 2007; 39: 1851-1857
- GIS or GPS? A comparison of two methods for assessing route taken during active transport.Am J Prev Med. 2007; 33: 51-53
Adult fitness test. President's Council on Fitness, Sports & Nutrition. http://www.adultfitnesstest.org/. Accessed March 11, 2013.
- Diagnostic performance of body mass index to identify obesity as defined by body adiposity: a systematic review and meta-analysis.Int J Obes. 2010; 34: 791-799
- The validity of BMI as an indicator of body fatness and risk among children.Pediatrics. 2009; 124: S23-S34
- Body mass index standards based on agreement with health-related body fat.Am J Prev Med. 2011; 41: S100-S105
- The evaluation of body composition: a useful tool for clinical practice.Ann Nutr Metab. 2012; 60: 6-16
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Published online: July 15, 2013
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© 2014 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.
