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Educating the Student Body
FIGURE 2-2
Percentage of students performing accelerometer-measured vigorous- or 
moderate-intensity physical activity for at least 60 minutes on at least 5 days per week, by 
grade.
SOURCE: Adapted from Pate et al., 2002.
Figure 2-2.eps
0
20
40
60
80
100
Pe
rcentage
Grades 
1-3
Grades 
4-6
Grades 
7-9
Grades 
10-12
BOX 2-3 
Measuring Physical Activity
Physical activity has been measured in multiple ways—self-reported 
measures (e.g., surveys, activity logs); instrumental measures (e.g., 
pedometers, accelerometers), often called “objective” measures; and 
direct observation—none of which are completely satisfactory.
Self-report surveys, 
in which youth are asked to provide informa-
tion about their physical activity behaviors, have been the most common 
method of measurement. They vary considerably in the detail requested 
and obtained. For example, the 3-Day Physical Activity Recall (3DPAR) 
asks about the predominant activity performed (a list of likely options is 
provided) and the intensity of that activity (light, moderate, hard, very 
hard) during each of 34 30-minute segments between 7 AM and midnight 
(Pate et al., 2003). The 3DPAR has been used with children as young as 
5th grade (Powell et al., 2009) but understandably has been used largely 
as a research tool. In contrast, the Youth Risk Behavior Survey (YRBS), 

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Educating the Student Body: Taking Physical Activity and Physical Education to School
Status and Trends of Physical Activity Behaviors and Related School Policies
 
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used to monitor a number of important health-related behaviors of youth, 
currently asks the following question: “During the past 7 days, on how 
many days were you physically active for a total of at least 60 minutes 
per day? (Add up all the time you spent in any kind of physical activity 
that increased your heart rate and made you breathe hard some of the 
time.)” Self-reported data have been and will remain important. It is 
relatively inexpensive to obtain and can provide information about what 
specific activities were performed, as well as where and why. The YRBS, 
for example, inquires about participation in physical education classes 
and on sports teams. Self-reported information also has important limita-
tions and weaknesses. Readers might try asking themselves the above 
question about physical activity during the past 7 days to realize how 
difficult it is to provide an accurate response. High school students likely 
are better than middle school students at answering such conceptually 
complex questions, and the questions as asked would be inappropriate for 
elementary school students—self-report has been discouraged as a mode 
of physical activity assessment for children less than 10 years old (Kohl 
and Hobbs, 1998). Moreover, even though students appear to answer 
personally sensitive questions (e.g., about their sexual behaviors) frankly, 
self-reported information is at risk of bias due to social acceptability and 
level of knowledge and experience. Self-reported data also are much more 
accurate for vigorous-intensity than for moderate- and light-intensity 
activities and generally overestimate the amount of vigorous- and 
moderate-intensity physical activity performed. Further, some studies have 
asked parents to provide information on the physical activity behavior of 
elementary-aged youth. The accuracy of parent proxy reports of children’s 
physical activity behavior has not been established.