Definition Measurement of Physical Activity Level and Fitness

The measurement of the patient’s physical activity level provides important clues regarding behaviors
that may contribute to the overweight condition. Sedentary behaviors are highly associated
with childhood obesity. There are very accurate laboratory procedures that can be used to determine
physical activity level. These include accelerometry, total energy expenditure by doubly labeled
water, VO2 portable equipment, heart rate monitoring by telemetry, time lapse or video photography,
and others [66]. However, the use of such methods is not feasible or cost-effective in primary care
settings. Likewise, direct observation techniques such as SOFIT and SOPLAY are impractical in
clinical settings. Several self-report questionnaires have been validated in youth 10 years of age or
older and are shown to be good predictors of physical activity level (Table 4.6). Samples of these
questionnaires may be found in Appendix A2.4.1.
Maximal oxygen uptake (VO2 max) is an indicator of physical fitness level in both adult and
youth populations [67–71]. The maximal oxygen uptake indicates the functional capacity of the
heart, lungs, and skeletal muscle and is generally assumed to be the single best indicator of physical
fitness [69]. The VO2 max is determined by exercising a subject and determining O2 intake and O2
and CO2 concentrations in expired air. All VO2 max tests should be supervised by trained and
certified exercise physiologists. Assessing cardiopulmonary fitness in the pediatric population has
become the focus of recent research in pediatric medicine and exercise science [72–76], Cardiovascular
responses to exercise stress can be evaluated by obtaining a value for submaximal steadystate
or peak or max exercise value (Peak or Max VO2). Maximal oxygen consumption (VO2 max)
has been used as an indicator of health related physical fitness [77]. The criteria for achieving a
Peak VO2 response in the pediatric population may not be similar to that of adults [78]. Obtaining
a plateau in oxygen consumption in children can oftentimes be difficult. However, there have been
several protocols that have been used and validated for pediatric exercise testing. In Chapter 10,
Rowland and Loftin detail appropriate fitness testing for overweight youth. Detailed exercise testing
protocols are also located in Appendix A2.4.2.
Psychological Testing
Because overweight children are at increased risk for depression, low self-esteem, and other related
psychological disorders, it is important that they be screened by an appropriate mental health
professional before treatment. Chapter 9 details the appropriate testing procedures for overweight
children. Sample referral forms and detailed psychological testing protocols are located in
Appendix A1 and A2.5.
Tanner Staging
Growth and development are affected by many complex factors. Various outcome measures could
reflect innate physiological factors rather than our proposed intervention outcome. To assess the
effects of nonmodifiable factors such as age and gender on measurement of growth (weight, height),
and body composition (lean body mass, percentage of fat), the sexual maturity rating may be
determined using methods from Falkner and Tanner [79] on all subjects at fixed intervals (baseline,
10 weeks, 6 months, and 12 months). Sexual maturity ratings (Tanner staging) should be performed
during the physical examination by a physician who is specially trained in adolescent medicine
(see Appendix A2.6). Alternatively, a self-report tool is available that allows the patient to selfexamine
his or her level of maturation [80].
The current environmental experience of young children includes few opportunities for physical
activity [81] and an overabundance of high-calorie foods. Sedentary lifestyles and poor nutrition
challenge children who are genetically predisposed to diabetes, heart disease, and other chronic
diseases. Obesity is a logical response to this challenge. Therefore, in predisposed children (e.g.,
those with obese parents and diabetes history), sedentary, nonnutritious environments challenge their
physiologic and metabolic capacity and promote overweight conditions, reduced fitness, further
inactivity, and increased sedentary behaviors (television watching and snacking). This results in a
clinically significant overweight condition (>95th BMI), reduced insulin sensitivity, and an increased
risk of type 2 diabetes and heart disease later in adulthood. Research indicates that increasing
physical activity and improving nutrition may significantly affect this series of events [82–84].
The current childhood overweight epidemic is neither the fault nor the responsibility of any
one single sector of society. All must work together to develop strategies to change public opinion
and behavior concerning healthy nutrition and physical activity across the life span. Because
children who are at risk for overweight at 7 years of age or older become increasingly more
susceptible as they mature, appropriate, targeted family-based dietary and physical activity interventions
should be made available in clinical settings. The economic burden of obesity-associated
illness during childhood in the United States has increased by 43% in the last two decades [85].
Cost-effective individual and group approaches are available and should be both encouraged and
financially supported by the medical community. More funds are needed for programs that work
simultaneously to conduct research and provide ongoing interventions to prevent and treat overweight
children in clinical settings. Physicians play a key role in these efforts to prevent and treat
overweight conditions, as the epidemic of childhood obesity is the most critical challenge facing
the medical community today.