Active Video Games to Promote Physical Activity in Children and Youth: Title and subTitle BreakA Systematic ReviewActive Video Games to Promote Physical Activity FREE

Physical inactivity is a well-established risk factor for many chronic conditions, such as diabetes, cardiovascular disease, and cancer,¹ and is estimated to cause 1.9 million premature deaths globally per year.² In 2004, the World Health Organization established the “Global Strategy on Diet, Physical Activity, and Health Promotion,” recognizing the key role that physical activity plays in disease prevention and promotion of lifelong health.³ Nearly half of preschool children⁴ do not meet recommended levels of physical activity (ie, ≥60 minutes daily) prescribed by the American Academy of Pediatrics.¹ Reported barriers to physical activity include a preference for indoor pastimes, low energy levels, time constraints, unsafe neighborhoods, a lack of motivation, not feeling competent or skilled, a lack of resources, and insufficient social support from parents and peers.^{1 ,5 - 10}

Many studies have explored strategies to reduce physical inactivity in youth. In a recent systematic review,¹¹ compulsory aerobic physical activity emerged as the common component of effective programs. However, enforcing participation in physical activity is resource intensive, and the long-term success of these interventions remains unknown.¹¹ Accessible effective strategies to encourage voluntary participation in daily physical activity are needed.¹² Activity choice is largely dictated by level of enjoyment,^{13 - 14} and the most frequently reported reason for participation in physical activity by children is “fun.”¹⁵ This same motivation drives competing interest in sedentary activities, including video game play. A typical child aged 8 to 10 years spends approximately 65 minutes per day in video game play.¹⁶ Eighty-three percent of American youth have access to at least 1 video game console in their bedroom.¹³ Evidently, screen time activities are highly valued by children, and attempts to restrict these activities are met with resistance.¹⁷

Instead of competing against a highly valued activity, an alternative strategy is to replace passive screen time with active screen time. Video games that require physical activity beyond that of conventional hand-controlled games are referred to as active video games (AVGs).¹⁸ The state-of-the-art in AVGs is constantly changing and is best accessed through popular media. For an introductory review of commercially available AVG systems, see the studies by Mears and Hansen¹⁸ and Trout and Christie.¹⁹

Active video gaming is an emerging technology with the potential to overcome many of the current barriers to physical activity in children. A recent review²⁰ of AVGs raises issues of long-term adherence while remaining cautiously positive about AVG play as a convenient exercise with low to moderate intensity to improve children's health and well-being. The goal of this review was to provide a more comprehensive and quantitative synthesis of the current state of knowledge pertaining to AVG play for physical activity promotion in children. Specifically, the objectives were (1) to systematically evaluate levels of energy expenditure and patterns of activity associated with AVG play in children and youth (≤21 years) and (2) to provide directions for future research and development of AVGs.

A systematic review of the literature via ISI Web of Knowledge, PubMed, and Scholars Portal was conducted using combinations of the following keywords (and their relevant suffixes): video game, exergame, physical activity, fitness, exercise, energy metabolism, energy expenditure, heart rate, disability, injury, musculoskeletal, enjoyment, adherence, and motivation. Additional studies were identified by reviewing bibliographies.

The search was limited to English-language communications in peer-reviewed journals published between January 1, 1998, and January 1, 2010, when the popularity of AVGs began to accelerate after the release of Konami's Dance Dance Revolution (DDR).²¹ Articles selected for in-depth qualitative review involved youth 21 years or younger and reported on (1) energy expenditure during AVG play, (2) promotion of physical activity through AVG play, (3) physiological risks and benefits of AVG play, and (4) enjoyment of and motivations for AVG play. Articles that targeted virtual reality rehabilitation, cognitive or behavioral therapies, or health education via computer and video games were excluded. Studies that used conventional video games or television as distracters during exercise activities were also excluded from this review. Only studies that reported on experimental results with mainstream AVGs and systems, such as the Wii, Sony EyeToy, XaviX, DDR, and Cateye, were included in the quantitative analyses.

Each article was examined by 2 reviewers (E.B. and J.I.) to authenticate data extraction and interpretation. Data extracted included (1) methodological details (eg, study design, experimental context, sample size, participant age, and outcome measures) and (2) key findings pertaining to energy expenditure (eg, heart rate [HR] and oxygen consumption) and the potential for physical activity promotion (eg, adherence, motivations for play, enjoyment, and reported changes in sedentary behaviors, activity patterns, body mass index, and anthropometric measurements). The quality of randomized controlled trials evaluating AVG interventions were further assessed using the PEDro (Physiotherapy Evidence Database) evaluation scale.^{22 - 23} This well-established checklist is used to quantitatively describe the internal and statistical validity of study designs, particularly with respect to allocation, blinding, and dropout rates.

Data extracted from experimental studies were summarized, tabulated, and compared. Quantitative measures of physical activity (ie, percentage increase from resting HR and energy expenditure) were compiled and statistically described in aggregate and with reference to different game types.

The Figure provides a flowchart documenting the results of the study selection process. Eighteen articles were included in the quantitative analyses. Studies targeting adults (>21 years old)^{21 ,24 - 29} were not included in the quantitative review. Methodological details and data extracted are summarized in Table 1 and Table 2 for energy expenditure and in Table 3 for patterns of activity and use of AVGs. The results presented herein are based on the data compiled in these tables.

Several studies^{13 ,30 - 40} have demonstrated the potential of AVG play to increase energy expenditure from levels observed during sedentary or passive video game activities in children and adolescents (Table 1). Energy expenditure, when adjusted for body composition, seems to be comparable for overweight and nonoverweight participants^{38 - 39} but may be higher for boys than for girls.^{30 - 31 ,35}

Sustained vigorous activity (eg, >6 metabolic equivalents of task) was generally not elicited during AVG play. Rather, AVG play was found to increase energy expenditure to light or moderate levels^{24 ,26 - 29 ,37} (ie, intensities similar to brisk walking, skipping, jogging, and stair climbing). Child-specific metabolic equivalents of task (as defined by Maddison et al³⁶ ) ranged from 2.0¹³ to 5.0³⁶ , with a mean (SD) of 3.3 (1) (n = 17). Table 2 tabulates these child-specific metabolic equivalents together with the percentage increases in HR and energy expenditure for a variety of AVGs. Energy expenditure during AVG play is highly variable, with percentage increases (from rest) ranging from 100%¹³ to 400%,^{13 ,36} with a mean (SD) of 222% (100%) (n = 21). Percentage increases in HR varied from 26%¹³ to 98%,¹³ with a mean (SD) increase of 64% (20%) (n = 17). For games that rely primarily on movements of the upper body (eg, bowling and tennis), the mean (SD) percentage increase in energy expenditure was 116% (15%) (n = 6) and in HR was 43% (10%) (n = 5). For DDR, which involves mainly lower body movement, the mean (SD) percentage increase in energy expenditure was 212% (49%) (n = 6) and in HR was 65% (13%) (n = 4). For games that require both upper and lower body movement (eg, boxing), mean (SD) percentage increases of 275% (86%) (n = 7) for energy expenditure and 75% (22%) (n = 6) for HR were observed. Percentage increases in HR (difference, −29%; 95% confidence interval, −47 to −11; P = .03) and energy expenditure (difference, −148%; −231% to −66%; P = .001) were significantly lower for games that require primarily upper body movements compared with those that engage the lower body as well. Evidently, energy expenditure largely depends on the game played, with more intense physical activity sustained during games that promote both upper and, especially, lower body movement.^{31 ,33 - 35 ,38}

Table 3 summarizes the results of several studies^{41 - 46} that evaluated the potential of AVG systems for physical activity promotion in the home. Preliminary evidence suggests that home play of AVGs may provide some moderate increase in physical activity or decrease in sedentary screen time.^{42 - 45} However, a variety of confounding factors and methodological limitations associated with these studies impede the strength of evidence presently available (Table 3). After 12 weeks, dropout rates ranged from 0%⁴⁴ to 41%.⁴² Other quantitative measures (eg, duration of play) were difficult to compare between studies owing to variations in methods and documentation. These are reported for each study in Table 3. In general, changes in physiological measures, such as body mass index, were not observed at a statistically significant level as a result of AVG play.^{44 - 45} To date, home-based studies have been relatively short (ie, 10⁴⁶ to 28 weeks⁴⁵ ). As such, long-term use and efficacy remain unknown, although several studies^{41 - 42 ,45} noted a decrease in AVG play during the study for reasons ranging from technical difficulties to illness or changes in living arrangements. Nevertheless, participants generally reported enthusiasm for and enjoyment of the AVG intervention.^{43 ,45 - 46} Group or competitive play with peers seemed to improve interest and participation in AVGs^{41 - 42 ,46} and is an important direction for future research.

Baquet et al⁴⁷ suggest that, to improve aerobic fitness in young people, exercise intensity must exceed 80% of the maximum HR (HR_peak). Only 2 studies^{39 - 40} (both with older youths) measured HR_peak. In each of these studies, average HR surpassed 60% of HR_peak during AVG play but did not exceed the 80% target. For rough estimations, an HR_peak of 200 beats/min⁴⁸ is often assigned for children with the understanding that HR_peak has a large degree of interindividual variability. With this limitation in mind, AVG play generally raises HRs to a mean (SD) of 61% (8%) of HR_peak, with a range of 50% to 80% based on the data presented in this review. In light of the current evidence base, participation in AVG play should not be regarded as a replacement for vigorous physical activity but can increase energy expenditure from sedentary or passive video gaming levels to that associated with light to moderate physical activity. These results agree with those of several studies^{32 - 35 ,37} in adults that also establish AVG play as a light- to moderate-intensity activity. In children and adults, activity intensity varies greatly among participants and games and is significantly greater for games that involve the lower body.

Nonprogrammed and lifestyle-related physical activities seem to be extremely important for sustaining weight loss and fitness.^{1 ,10} Provision of nonstructured opportunities for physical activity is in line with the American Academy of Pediatrics recommendations, which advocate the increase in structured and nonstructured physical activity of mixed forms (ie, team, individual, competitive, and noncompetitive).¹ With indoor time increasingly dedicated to inactive pastimes,⁴⁹ expansion of home-based opportunities for physical activity is essential. The AVGs are not constrained by typical barriers to participation, such as unsafe neighborhoods, lack of transportation, and seasonal conditions.⁵⁰ Although AVGs eliminate many of these environmental barriers, spatial (eg, arrangement of furniture and television in multipurpose living areas) and auditory (eg, jumping or stepping may be disruptive in multilevel or shared living spaces such as apartment buildings) barriers to daily use have been reported.^{21 ,41 - 42} At this stage, the potential of AVG play for significantly decreasing childhood physical inactivity is inconclusive, although preliminary results of short-term interventions indicate some promise, particularly when opportunities for group play are provided.^{42 - 45} Further research is greatly needed to strengthen the evidence base surrounding this emerging technology, which is, at present, relatively weak. Further study in this area must explore the long-term use and efficacy of AVGs and the changes to sedentary and physical activity patterns that they generate.

The second objective of this article was to provide directions for future research based on the findings of this review. The following subsections present a variety of areas in need of focused research efforts.

Unlike traditional sports, AVG play is not limited by physical strength, endurance, and training, which provide protection against upper extremity overuse syndrome, delayed-onset muscle soreness, and acute muscular and myotendinous strain.⁵¹ Minimal data are available on injury rates and quality of movement during AVG play. Several case studies^{51 - 53} have reported Wii-related injuries due to prolonged or overly aggressive play. Tan et al⁴⁰ reported no injuries during 201 hours of DDR play, which compares favorably with injury rates of 2.44 per 100 hours for runners. With the growing popularity of AVGs, research is needed that quantifies injury rates and the forces and eccentric loads exerted by muscle groups during play. This understanding would be beneficial for the development of prescriptive guidelines for physical activity, physical therapy, and general public health.

It is unknown how well estimates of energy expenditure conducted in a laboratory setting translate to the home environment, where AVG play is often episodic and unsupervised. In the future, games may be designed to minimize interruptions and to promote higher levels of activity with healthy rest periods. Success in the game may be linked to energy expenditure measured using lightweight wearable sensors.⁵⁴ The AVGs that encourage higher levels of stable physical activity while limiting the use of low-energy strategies (eg, a wrist flick in lieu of a swing in Wii Tennis) should be the focus of further developments. Systems such as the Sony EyeToy and new concepts for the Xbox 360 that translate body motions directly to on-screen play may achieve this goal. Advanced methods that enable game designers to simulate the physiological responses of players in the development and testing stages may also facilitate the creation of optimized systems to maximize the health benefits of the AVGs of the future.⁵⁵

Significant changes in physiological outcomes were generally not observed in the studies reviewed. A focus solely on weight loss or body mass index may, however, miss other important benefits rendered by physical activity,¹ including measures of fitness (eg, cardiovascular endurance, muscular endurance, muscular strength, balance, body composition, and flexibility) and changes in sedentary behaviors. Independent of increasing exercise time, reducing sitting time is vital to metabolic health.⁵⁶ As emphasized by Pate,⁵⁷ research targeting the behavioral aspects of AVG play is absolutely essential to the design and evaluation of AVGs, particularly with respect to the possible displacement of alternative activities that are either more sedentary (positive outcome) or more active (negative outcome). As such, it is important to understand how the introduction of AVGs affects the entire activity profile.

Self-initiation and choice are important factors that motivate engagement in physical activity for children.⁵⁸ The self-determination theory posits that initiation and continued performance of behaviors is driven and predicted by factors such as enjoyment, mastery, and achievement.¹² The development of games that spark these intrinsic motivators in individuals of all ages and levels of physical ability is needed. The following strategies, based on the principles of behavioral economics,⁵⁹ should be considered in the design of future AVG systems and interventions: (1) AVGs must provide positive reinforcement and be an accessible (ie, low-cost and easy-to-use) alternative to sedentary activity; (2) early exposure to active in lieu of passive games may increase their acceptance, suggesting the need for games that appeal to a wide range of ages and interests; (3) use of AVGs may be more prolonged and acceptable when perceived as a personal choice as opposed to a treatment or therapy; and (4) immediate reinforcement (eg, enjoyment and points) in addition to continued or long-term reinforcement (eg, progress toward goals and skills development) is important. Future research should address the individual's ability to set and attain goals, to initiate activity, and to achieve recommended intensities and durations of physical activity for a prolonged period.¹² To date, home-based studies have been relatively short (ie, ≤28 weeks⁴⁵ ). Long-term adherence and efficacy remain unknown. Strategies (eg, diversifying games provided, incorporating a story or plot development into games, and providing opportunities for group play) to maintain interest and enthusiasm in active play with AVGs require further exploration.

Mueller et al⁶⁰ proposed the value of “sports over a distance” that enable individuals to motivate, participate, and compete against friends regardless of location. The AVGs offer opportunities for group play nonlocally (ie, over the Internet) or in a local setting. For example, in 2006, West Virginia introduced multiple DDR consoles into its schools' physical education programs.⁶¹ The current evidence base supports the hypothesis that group play encourages participation in AVG play.^{42 ,46} There are many opportunities for research in this area, including the exploration of virtual and nonvirtual AVG clubs to encourage group and competitive play to maximize acceptance and enjoyment of AVGs for physical activity and health.

For individuals with physical and cognitive disabilities, the physical, social, and environmental barriers to physical activity can be even greater.¹⁰ Providing expanded opportunities and promoting physical activity for children and adolescents with disabilities is a key priority in government health policy.⁶² Active video games may be particularly suited to children with disabilities who spend more time alone and engaged in sedentary activities than do their able-bodied peers.⁴⁹ A few studies have used AVGs to elevate enjoyment of physical therapies in individuals with cerebral palsy,^{63 - 64} stroke,⁶⁵ burns,⁶⁶ spinal cord injury,⁶⁷ and spina bifida.⁶⁸ To our knowledge, no studies have evaluated energy expenditure elicited by AVG play in children with disabilities or have explored the potential of this pastime for increasing physical activity, independent of rehabilitation. Only 1 study⁶⁹ has explored the potential use of an AVG adapted for virtual rehabilitation in the home. In this study, 5 children with hemiplegic cerebral palsy were provided with a system based on the Sony EyeToy for 10 days. The children enjoyed having the AVG system at home and used it for a mean (SD) of 29 (32) minutes per day.⁶⁹ A final study⁷⁰ exploring the potential of AVGs as a leisure activity in adults with intellectual and physical disabilities also observed high levels of enjoyment of this activity. More research is needed to develop prescriptive guidelines for the safe use of AVGs for individuals with disabilities⁷¹ and to determine appropriate measures to evaluate fitness outcomes; body mass index, for example, has been shown to have limited applicability to children with physical disabilities.⁶²

This study provides a systematic overview of the current state of knowledge and identifies a variety of opportunities for future research. The timing of this study is opportune given the growing prevalence of and interest in AVGs as an avenue for recreation, health promotion, and rehabilitation. This review provides important guidelines for future research and development in this area to ensure that the health and safety of children is protected while optimizing the health value of AVG play.

Limitations of this study are as follows. Regarding energy expenditure measurements, nonstandardized protocols may have contributed to some of the variations observed among studies. The current evidence base does not allow for strong conclusions to be drawn regarding daily use of AVGs in the home or their efficacy to promote physical activity or reduce sedentary behaviors. Quantitative interstudy comparisons of activity patterns were not feasible owing to variations in study methods (eg, study duration and outcome measures) and reporting (eg, units of measurement and variations in descriptive statistics reported). The randomized controlled trials included in this review were associated with a median score of 6 on a 10-point scale as assessed using the PEDro evaluation tool. The most common risks for bias included unconcealed allocation, lack of blinding (where possible), and selectively reported outcomes. Dissimilarities between control and intervention groups at baseline were often problematic given the small sample sizes. To strengthen the current evidence base, it is important to address these limitations in the design and dissemination of future studies evaluating the efficacy of AVG play for physical activity promotion.

Physical inactivity in children and youth remains a significant health issue that will likely be solved only through a multifaceted approach that includes education and structured interventions combined with the provision of enticing opportunities for voluntary daily physical activity. New-generation AVGs are an emerging technology that have recently entered the health care arena with promise to address the latter. Preliminary evidence seems to support AVG play as an enjoyable medium for self-directed physical activity of light to moderate intensity. It remains to be seen whether AVGs can be used effectively in the long term to help motivate increased daily physical activity and decreased sedentary pastimes. The AVGs designed to engage both the upper and lower body while providing opportunities for multiplayer participation may improve the quality and enjoyment of this activity. Providing accessible and appealing options for physical activity in the home will overcome many reported barriers to physical activity, particularly for high-risk disability groups.

Correspondence: Elaine Biddiss, PhD, MASc, BAS, Bloorview Research Institute, 150 Kilgour Rd, Toronto, ON M4G 1R8, Canada (elaine.biddiss@utoronto.ca).

Accepted for Publication: January 13, 2010.

Author Contributions: The authors had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Biddiss. Acquisition of data: Biddiss and Irwin. Analysis and interpretation of data: Biddiss and Irwin. Drafting of the manuscript: Biddiss and Irwin. Critical revision of the manuscript for important intellectual content: Biddiss and Irwin. Statistical analysis: Biddiss and Irwin. Obtained funding: Biddiss. Administrative, technical, and material support: Biddiss and Irwin. Study supervision: Biddiss.

Financial Disclosure: None reported.

Funding/Support: This study was supported by the Natural Sciences and Research Council of Canada, by the Canadian Institutes of Health Research, and by the Bloorview Kids Foundation.