Abstract
Exercise games were developed by video game designers to combat sedentary behavior. The purpose of this study
was to explore the intensity levels of exergaming in comparison to an unstructured physical activity program.
Sixteen female participants (Mean age=9.4 ± 1.0 years) spent twenty minutes in unstructured physical activity,
monitored by a mentor, and twenty minutes playing exercise games on the Nintendo Wii™. Based on our findings,
it can be concluded that only the WiiFit exergame can achieve intensity levels comparable to unstructured activity.
Introduction
The nationwide prevalence of obesity in all
age groups has risen drastically over the past decades and is often attributed to the dramatic increase in sedentary
behaviors as a result of the technology boom (Wang & Beydoun, 2007). It has been proposed that childhood
and adolescence is the most critical period for the development of obesity, and such a proposition has made the
prevention of obesity in children a public health priority (Wang & Lobstein, 2006). It was noted that
children’s play has moved from the streets and playgrounds to the couches and television screens. Specifically,
recent studies showed that children spend two to five hours per day in front of television and/or computer screens
(Vandewater, Bickham, & Lee, 2010). In fact, Anderson, Economos, and Must (2008) found that 61.5 percent
of children in a nationally representative survey had not engaged in any organized physical activity outside
of school in the previous 7 days, and 23 percent had not engaged in any physical activity at all.
Two factors that are believed to play a role in the increase in sedentary behavior in children are a perceived
lack of neighborhood safety (Dixon et al., 2010; Farley et al., 2007) and a decreased level of physical activity
in adults (Anderson, Economos, & Must, 2008). If parents do not perceive their neighborhood to be safe for
children to play outside, they will discourage their children from playing in their front yards or on local playgrounds.
Veitch and colleagues (2010) found that activity levels (as measured by accelerometers) were much higher for
children whose parents perceived their neighborhood to be safe than for those that did not. Moreover, if parents
are not setting an example for their children and engaging in physical activity themselves, there is a slim possibility
that their children will have the motivation and the opportunity to be physically active and therefore will choose
more sedentary activities (Anderson, Economos, & Must, 2008). Furthermore, physically inactive parents are
less likely to enroll their children in physically engaging activities such as recreational sports due to their
own lack of ability and interest.
A third and perhaps most influential factor in the increase in sedentary behaviors of children is the immense
increase in technology over the past few decades. With the vast expansion of video game systems, sedentary game
play has become a preferred method of play for many children. More children than ever before spend the majority
of their playtime seated in front of a screen, an activity with incredibly detrimental consequences. Anderson
and colleagues (2008) found that 77 percent of obese girls had high screen time as compared to their healthier
counterparts. Screen time, according to the authors, is any time spent in front of a screen of any kind, be it
a television, video game system, computer, or anything of that same nature. Furthermore, with the increased ability
for social interaction on video games, children no longer have to depend on physical activities such as team
sports and playground activities in order to develop relationships (Veitch, Salmon, & Ball, 2010). As a result,
even less time is spent in unstructured active play and more time is spent engaging in sedentary video games.
The American College of Sports Medicine (ACSM, 2008) recommended that children engage in 60 minutes of moderate
to vigorous activity daily. Furthermore, the guidelines recommend at least three days per week be spent engaging
in physical activity that focuses on strengthening muscle and bone. The ACSM does not specify any precise ways
in which children should attain the recommended 60 minutes of activity. In an effort to assuage the detrimental
impacts of sedentary videogames on children’s health, video game researchers developed exercise games or
exergames. These games attempt to get children off the couch and physically engaged while they participate in
games on consoles such as the Nintendo WiiÔ. Many studies have shown that exergames played over short periods
of time may be of similar in intensity to traditional physical activities such as walking, skipping, and jogging
(Graf, Pratt, Hester, & Short, 2009).
Long-term interventions with active video games have shown their potential to improve body composition, cardiorespiratory
fitness, and physical activity levels in overweight children (Maddison et al., 2009). Maddison et al. (2009)
distributed over 150 active video game upgrade packages for the Sony Eye Toy® to children age 10-14. The
children were encouraged to use the video games to meet the recommended daily amount of physical activity. It
was found that over 12- and 24-month periods, the children who used active video games decreased their BMI, increased
their cardiorespiratory fitness, and decreased their percent body fat. Dance Dance Revolution™ (DDR), a
game initially popular in arcades but then made available for home use, has been demonstrated to engage players
in moderate to vigorous levels of physical activity (Tan, Aziz, Chua, & Teh, 2002; Unnithan, Houser, & Fernhall,
2006). The game requires participants to follow patterns of arrows that occur on screen with full-body movement.
As the arrows flash across the screen participants have to jump from the corresponding arrows on a dance pad
located on the floor. In fact, a four-month intervention study found that children with access to DDR decreased
sedentary screen time and increased vigorous physical activity levels more than children who did not have access
to the exergame (Maloney et al., 2008).
Furthermore, acute interventions have shown that exergames can increase activity levels better than non-active
video games. One study found that playing DDR for ten consecutive minutes at a difficulty of “medium” elicits
heart rate ranges of 65-70 percent of heart rate maximum (Tan, Aziz, Chua, & Teh, 2002). Researchers recorded
heart rate before participants engaged in a ten-minute session of medium-difficulty DDR songs and immediately
following the ten minutes. They found not only that heart rate was elevated to within the ACSM’s recommended
range for moderate activity but that participants’ rate of perceived exertion indicated that they felt
as though the exercise was of moderate intensity as well. Another study found that playing ten minutes of WiiSports
boxing elicited higher heart rates than ten minutes of treadmill walking at 1.5 miles per hour or ten minutes
of non-active video game play (Penko & Barkley, 2010).
Additionally, it was found that both parents and children are interested in engaging in interactive video games
as a means of obtaining physical activity (Dixon et al., 2010). In their study, Dixon and colleagues (2010) interviewed
parents and children (ages 10-14) in 11 different focus groups after allowing them to play interactive video
games such as the Sony Eye Toy® and Dance Dance Revolution™. Both children and parents reported feeling
as though the games allowed them to engage in physical activity and were enjoyable as well.
Because so many children are now turning
to sedentary behaviors such as video games instead of active forms of play, it is necessary to find a way in
which to engage children’s interest as well as get them moving. The use of exergames could prove to be
the link between the technology boom and increasing physical activity in children. The purpose of this study
was to investigate the intensity levels of exergaming in comparison to unstructured activity to determine if
exergames can be used as a viable intervention for increasing the amount of physical activity amongst children
in the United States.
Methods
Participants
Thirteen girls (age = 9.4 ± 1.0 years, height = 56.2 ± 3.9 inches, weight = 108.3 ± 12.9
pounds) were recruited from the Alamance Girls in Motion program at a small southeastern university. Girls in
Motion is a national eight-week program that seeks to address the issues of body image, self-esteem, and healthy
eating for girls age 9-11. The goals of the program are to build a positive body image and self-esteem in young
girls, prevent obesity and eating disorders, develop healthy attitudes about food and exercise, and utilize young
women as positive role models and mentors for young girls (Girls in Motion, 2011). At the orientation session,
parents were briefed on the experiences that their daughters would have if they chose to participate in the research.
If the parents decided that their daughter could participate in the research, they signed informed consent forms
that were approved by the University’s Institutional Review Board.
Measures of Exercise Intensity
Subjective measures of exercise intensity.
The Borg Rating of Perceived Exertion (RPE) scale was used to measure perceived exertion. This scale ranges from
6-20, with 6 being “no exertion at all” and 20 being “maximal exertion” (Borg, 1998).
Objective measures of exercise intensity.
Exercise intensity was measured with accelerometers and heart rate monitors. The accelerometer data was coded
such that 60 second epochs of time for each condition was categorized as either light intensity or moderate intensity
based on cut points determined by Freedson, Pober, and Janz (2005). Total minutes of light and moderate intensity
exercise were summed for each of the games. Heart rate was recorded with a Polar heart rate monitor. Participants
placed the monitors around their chest, and recording watches were worn around the wrist.
Procedures
Data collection was divided into two sessions, one lab session and one unstructured activity session. Participants
were randomly selected to either participate in the lab session or the unstructured activity session first. Before
the data collection began, height and weight were measured, and the participants were briefed on the activities
in which they would be engaging.
The lab session consisted of participants playing two games on the WiiFit game (hula hoop and running) and two
games on the WiiSports game (tennis and boxing). Before beginning their sessions, participants were fitted with
a heart rate monitor (Polar, Lake Success, NY) and an accelerometer placed at the right hip (Actigraph model
GTM1). Each participant spent ten minutes playing WiiFit and ten minutes playing WiiSports. During the
ten minutes, participants were allowed to randomly choose between two different activities that were determined
by the researchers prior to the testing. At two different times (5 min during the activity and at the end of
the activity), the participants were asked their rate of perceived exertion (Borg 1998). Additionally, the researchers
recorded heart rate at three time periods (before the activity, 5 min during the activity, at the end of the
activity).
The unstructured activity session involved a twenty-minute period of time in which the participant was with
her mentor doing whatever activities she chose. The mentors were a selected group of female college students
who agreed to participate in all eight weeks of the program and were individually assigned to the participants
before the research began. Before their activity time began, halfway through their time (10 min.), and at the
end of the twenty minutes, the mentors were instructed to record the heart rate. RPE was recorded at 10 minutes
during the activity and the end of the activity. At the end of the twenty minutes, the mentors and their partners
returned to the lab.
Data Collection
A Game (3: Wii Fit, WiiSports, unstructured
activity) by Time (depending on variable) Repeated Measures General Linear Model (RM GLM) was used to determine
main and interaction effects of condition and time (within-subjects repeated measure) for each of the variables.
Results
A 3 (Condition) x 3 (Time: pre, middle and post) RM GLM for heart rate revealed a significant condition effect
(F (2, 11) = 20.02, p < .001), time effect (F (2, 11) = 77.12, p < .001),
and condition*time interaction (F (4, 9) = 6.06, p = .012). The condition effect was
due to a greater heart rate during Wii Fit compared to unstructured activity (p = .023) and Wii Sports
(p < .01). There was not a statistical difference between unstructured activity and Wii Sport (p =
.070). See Figure 1 for graphical analysis of data.
Figure 1. Heart rate vs. Time for the 3 Exercise Conditions
A 3 (Condition) x 2 (Time: middle and post) RM GLM for RPE showed a significant effect for time (F (1,
13) = 6.82, p = .022), but not for condition (F (2, 12) = 1.99, p = .179). No condition*time
interaction was observed (F (2, 12) = 3.20, p = .077). The time effect was due to RPE being
greater following exercise compared to during exercise (See Figure 2).
Figure 2. Ratings of Perceived Exertion vs. Time for the 3 Exercise Conditions
A RM GLM found a significant difference for condition (F (2, 13) = 17.15, p < .001) that
was due to greater moderate activity in the unstructured activity, 75.2 percent of minutes compared to Wii Fit,
66.1 percent of minutes (p < .001), and Wii Sports, 32.1 percent of minutes (p < .001).
There was not a statistical difference between Wii Fit and Wii Sports (p = .091).
Discussion
Based on our findings, the WiiFit exergame may be a superior exergame strategy to the Wii Sports exergame.
Specifically, it was found that heart rate was highest at the end of the WiiFit session as opposed to the Wii
Sports session. Additionally, it may be fair to assert that WiiFit may elicit physical activity participation
of similar intensity to unstructured activity. Because the heart rates achieved during the WiiFit condition were
higher than the unstructured activity session, it can be assumed that the WiiFit has similar overall benefits
to the already known benefits of unstructured activity in children (Veitch, Salmon, & Ball, 2010). As such,
parents can encourage their children to participate in exergames such as the WiiFit and have confidence that
the children are working towards their recommended 60 minutes of moderate activity every day. Additionally,
exergames have the potential to be viable and enticing physical activity interventions for children.
Our findings indicate that the mean RPE for the participants in the WiiFit condition was 17, which is reflective
of “moderately difficult.” Furthermore, the participants’ mean heart rate for the WiiFit condition
was 170, which is roughly 80 percent of the age-predicted heart rate max for children of this age demographic.
As such, our findings show that the WiiFit elicits heart rate intensities that are considered moderate to vigorous
by the ACSM. These findings are similar to those found through the short-term DDR studies (Maloney et al., 2008;
Tan, Aziz, Chua, & Teh, 2002).
Additionally, our findings supported the hypothesis that exergames such as the WiiFit can be used as an alternative
to unstructured activity to help children achieve their recommended levels of physical activity. Our results
showed that for both RPE and heart rate intensities, WiiFit time and unstructured activity time had similar values.
These results are similar to those found by Graf and colleagues (2009), who reported that Wii Boxing and DDR
were of comparable intensity to walking at a moderate pace. As such, children who need to improve their fitness
for weight maintenance as well as those who need to engage in activity to maintain a healthy lifestyle can use
exergames as a means to obtain their activity levels.
Because the current technology craze has led to a drastic increase in screen time, it is important that exercise
interventions be geared toward technological advances (Dixon et al., 2010). Exergames such as the WiiFit allow
for children to engage in video games yet also increase their energy expenditure and thus can be used to help
combat the obesity epidemic. The findings of this study are similar to those of other studies that have shown
that various exergames can help children achieve moderate to vigorous levels of physical activity (Tan, Aziz,
Chua, & Teh, 2002; Unnithan, Houser, & Fernhall, 2006). Unnithan and colleagues (2006) showed the importance
and relevance of exergames as physical activity interventions when they compared overweight to non-overweight
children playing DDR. They found that overweight children who played DDR displayed higher energy expenditure
levels than non-overweight children, thus demonstrating that exergames could help children get fit and maintain
fitness levels (Unnithan, Houser, & Fernhall, 2006).
There are a few potential limitations to
this study. Although significant differences were found amongst heart rates for the different conditions, it
can be said that increasing the number of measurement points for heart rate would increase the validity of the
results. With the collection of more heart rate data points (i.e., at every minute or with every change in activity),
more specific results as to the role each game plays in overall physical exertion could be obtained. Furthermore,
the placement of the accelerometers on the hip could have limited the measurement of overall body movements,
as many Wii games primarily involve upper extremity movement that wouldn’t necessarily be picked up on
the hip accelerometer (Choi, Chen, Acra, & Buchowski, 2010). Lastly, although all of the college mentors
for the participants of Girls in Motion are given various topics to focus on each session, they are also given
a lot of freedom in activity choice during their free-play time. As such, some participants spent their time
walking, others spent it playing structured games such as volleyball, and still others spent their time doing
seated activities. As a result, broad interpretations of energy expenditure during free time were made, and thus
may not give an accurate depiction of unstructured activity.
Future studies may be warranted to address potential psychological benefits resulting from long-term exergame
participation. Besides the various studies showing the potential physiological benefits of exergames, it has
been shown that engaging in exergames provides a high level of motivation for otherwise inactive children. Specifically,
it has been found that overweight children are equally motivated to play inactive video games and exergames (Penko & Barkley,
2010). Additionally, it is proposed that the novelty of exergames may provide more motivation than traditional
outdoor activities such as walking, jogging, and skipping (Graf, Pratt, Hester, & Short, 2009). Lastly, it
is proposed that exergames will provide children with an opportunity to try a wide range of activities that they
might not otherwise experience. As such, children might be more likely to engage in the authentic activities
and thus increase their physical activity levels (Daley, 2009). Thus, examining psychological factors such as
affect and enjoyment of activities will provide information about children’s willingness to engage in exergames
for an extended period of time.
Conclusions
It has been shown that the WiiFit exergame
elicits physical activity levels similar to that of unstructured activity. As such, it is proposed that exergames
such as the WiiFit can be used to help children achieve their recommended 60 minutes of daily physical activity.
Additionally, the WiiFit game has been shown to improve other important aspects of motor development in children
such as postural control and kinesthetic awareness (Fitzgerald, Trakarnratanakul, Smyth, & Caulfield, 2010).
These findings could serve to help combat the current issue of physical inactivity amongst children and adolescents
in an effective way, as well as improve children’s overall motor development and coordination.
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Note: We would like to thank Professor Liz Bailey for her willingness to let us recruit participants
and mentors from her Girls in Motion program.