Project Coach Enhances Activity Levels Beyond what
Youth Get When on their Own
Don Siegel and Dennis Nelson
A recent meta-analysis (Metcalf, Henley, and Wilkin, 2012) concluded
“physical activity interventions have had only a small effect on children’s
overall activity levels.” The authors speculate that one reason for such modest
effects may be “… that the intervention specific exercise sessions may simply
be replacing periods of equally intense activity. For example, after school
activity clubs may simply replace a period of time that children usually spend
playing outdoors or replace a time later in the day/week when the child would
usually be active.” In our continuing attempt to examine the quantity and quality
of Project Coach components, and to determine whether our Fall soccer program
was impacting the amount and quality of physical activity enjoyed by our 3rd
to 5th graders, we ran our most extensive accelerometer study to
date. In essence, one of our goals was to determine whether Project Coach
reflected the findings of Metcalf, Henley, and Wilkin, or promoted enhanced
activity, beyond what youth get when on their own.
What We Did
After coordinating with teachers and children at Gerena School, 10
youth (7 boys and 3 girls, 10 years of age) volunteered to wear accelerometers
(Actigraph GT3X) for 8 days, from when school started at 8:30 a.m. until 5:30
p.m. The strategy was to collect data
for 4 days when these participants had Project Coach and 4 days when they did
not have Project Coach after school. During this time of the year we run our
soccer/dance program on Tuesdays and Wednesdays from 4:30 – 5:30. On Mondays
and Thursdays, participants simply wore the accelerometers over the same
duration and attended to whatever activities that they normally do after school.
To provide a broader context for the activity levels of our youth,
we broke down data hourly so that we could get a sense of how much activity
children were getting during the school day, when participating and not
participating in Project Coach, and when taking physical education. Using
Actilife 6.0 (accelerometer data analysis software), we were able to convert
accelerometer activity counts to calories expended, MET rate (a measure of
activity intensity), percentages of sedentary to very vigorous activity, and
steps taken.
What We Found
Figure 1 shows the calories expended by participants in various
conditions. During the school day (8:30 – 3:30) participants burned 23
calories, on average, for each hour that they were in school. In contrast,
during the 4:30 – 5:30 period on days that they did not have Project Coach
(NonPC KCal) they burned 51 calories. During Project Coach participants
expended 126 calories, and during physical education they burned 73 calories
(physical education lasted only 40 minutes). Statistical tests run across these
conditions (p. < .05) revealed that youth expended more calories during
their non Project Coach hour than an average school hour, and that during Project
Coach they burned more calories than during the same 4:30 – 5:30 hour when they
were not in Project Coach. Tests also revealed no difference between a child’s
out of school - non-Project Coach hour and physical education [1].
We did not include dance in the statistical analysis as only 2 children were in
dance, but presented data to get a general sense of how it compared to soccer.
 |
| Figure 1. Caloric expenditures in different conditions. |
As seen in Figure 2, we also report the conversion of accelerometer
activity counts to steps. The contrast between the non- Project Coach hour and
that in Project Coach is similar and statistically significant, but the average
in-school and non-Project Coach hour are statistically not different. Also, the number of steps taken in physical education are greater
than during a normal school hour or a non-Project Coach hour, but are
statistically less than in Project Coach.
 |
Finally, in Figure 3 we contrast the activity intensity levels
across conditions. These data were derived by using Freedson’s (2005) algorithm
for converting activity counts to metabolic equivalents with the following
cut-offs (Sedentary 0-2.0 METs, Light 2.0 – 2.4 METs, Moderate 2.4 – 6.3 METs,
Vigorous 6.3 – 10.3 METs, and Very Vigorous > 10.3 METs). As shown, Project
Coach has the lowest amount of sedentary activity (combining PC and Dance), and
the highest amounts of moderate activity. It also appears that physical
education has a comparable level of vigorous activity to that of Project Coach.
When we computed an average for the percentage of moderate and vigorous
physical activity (MVPA) for children when they were not in Project Coach and
when they were, we found the difference to be dramatically, and significantly
different (29.0% vs. 71.9%, p. < .001). Such data, also compare quite
favorably with an accelerometer study by Wickel and Eisenmann (2006) who
reported that children, when engaged in youth sports had MVPA of between 22% –
27% of the time, and were engaged in sedentary and light activity approximately
52% of the time.
While recommended caloric expenditures for
children are not readily available, the American College of Sports Medicine
does endorse children taking 12,000 steps/day[4]. If
we were to add the number of steps youth in our study took over the hours of
8:30 to 5:30 on a non- Project Coach day and a Project Coach day, we get approximately
6800 and 8400 steps, with Project Coach accounting for about 18% of the total.
Again, from a policy perspective, if the 12,000 steps/day goal is to be attained
for our youth, more physical activity is needed. This can be achieved by
increasing the intensity level of what is done in Project Coach (although over
70% is already at the moderate to vigorous level), increasing the duration of Project
Coach activity periods (e.g., going from 60 minutes to 90 minutes), and/or by providing more periods during the
school day when children have an opportunity to be active (e.g., increasing the
number of days children have physical education from 2 days to 4 or 5 days, and
providing daily recess during which children can engage in free play). Our data show that children, on average,
spend 77% of their school day engaged in sedentary or light activity).
 |
What Do these Data Mean?
While Project Coach continues to work on
increasing activity levels in which its participants engage, these data do seem
to conflict with the findings of Metcalf, Henley, and Wilkin (2012) in that
children participating in Project Coach clearly are getting more physical activity
that has greater intensity than they are getting on their own [2]. In relative terms, this amounts to burning
147% more calories and taking 259% more steps during the 4:30 – 5:30 hour. The
fact that youth in Project Coach are getting more activity than they do obtain
on their own is not accidental in that we have been monitoring activity levels of youth by using accelerometry for
several years, and have adapted our coaching practices to minimize sedentary
epochs, reduce transition time among drills and games, and instruct coaches on how
to lessen “talk time”. We also make it a point to reinforce coaches as they
improve on maximizing activity levels of their players. As with most structured
physical activity programs, there is nothing magical about increasing a child’s
physical activity level. Simple enrollment in a program is not enough. How the
program leaders utilize time and engage children determines participants’
physical activity profiles. Normally, when children are having fun, learning
new skills, and given opportunities to play games with minimal disruptions,
their physical activity levels increase.
While the data also reveal that for the time children are in Project
Coach they are getting the dosage of physical activity recommended by the
Center for Disease Control and Prevention and the National Association for
Sport and Physical Education[3],
we also recognize that youth in this study are most likely not getting at least
an hour of physical activity every day, with most of it being at a moderate to
vigorous level. Consequently, if such guidelines are to be met, additional
programming by Project Coach is needed, or other school and community
initiatives should be undertaken to provide more structured opportunities for
youth to engage in such programs.
We are also aware that in absolute terms the
number of calories expended and steps taken are fairly modest (US Department of
Health and Human Services, 2008). However, as conveyed by Freedson, Pober, and
Janz (2005) accelerometry counts do not perfectly track physiological indices
such as calories expended or metabolic equivalents (METs), since they do not
capture “…all movement all the time and thus estimates of total daily energy
expenditure from movement counts underestimate actual energy expenditure” (p.
S526). Additionally, the data reveal
that approximately 28% (about 17 minutes) of the time youth are in Project
Coach they are sedentary or engaged in light activity, which would also contribute to these
relatively modest values. To place our
findings in context, using data from a recent study that computed caloric
expenditures in children, aged 10 – 13, for an array of activities, using
indirect calorimetry, the 43 minutes of activity in Project Coach was as if youth walked continuously at 3 mph
(Graf, et al., 2009). Consequently, it
is reasonable to surmise that the actual data represent conservative estimates
of physiological values, and that if more direct measures had been taken, it is
likely that we would find higher values for calories expended, percentage of MVPA,
and steps taken.
While Metcalf, Henley, and Wilkin (2012) have not found compelling
evidence for the added value of structured physical activity programs; such
data need to be interpreted with regard to the contexts in which youth live and
the opportunities that they have to be physically active. For children living
in the North End of Springfield, and many other such locals in which parents are
apprehensive about allowing their children unstructured and unsupervised free
play, it would seem that well conceived programs within schools and during the
after school hours should be crafted, supported, and promoted.
References
Freedson, P., Pober, D.,
& Janz, K. F. (2005). Calibration of accelerometer output for children.
Medicine & Science in Sports & Exercise, 37(11), S523-s530.
Graf, D. L., Pratt, L. V., Hester,
C. N., & Short, K. R. (2009). Playing active video games increases energy expenditure
in children. Pediatrics, 124(2), 534-540. doi:10.1542/peds2008-2851.
US Department of Health and
Human Services. Physical activity guidelines for Americans, 2008. Washington,
DC: US Department of Health and Human Services; 2008.
Wickel, E. E., & Eisenmann, J.
C. (2007). Contribution of youth sport to total daily physical activity among
6- to 12-yr-old boys. Medicine & Science in Sports & Exercise, 39(9),
1493-1500.
Notes:
[2]
Children should accumulate at least 60 minutes, and up to several hours, of
age-appropriate physical activity on all, or most days of the week. This daily
accumulation should include moderate and vigorous physical activity of which
the majority of it is intermittent in nature.
[3]
Wickel and Eisenmann (2006) also found that youth were physically more active
with regard to both the amount and intensity of activity on days that they were
engaged in a structured sports program than on days when they were not so
engaged.
[4]
Again, physical education was only 40 minutes in duration, and given the trend,
we would expect to find significance if physical education was 20 minutes
longer in duration.
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