Despite recognition of climate change by scientists for well over a century, it has gained widespread attention only in recent years.^14,15 Among its other impacts, climate change has increased average global temperatures and the intensity, frequency, and duration of heat waves,¹⁶ which reduce physical activity due to thermal discomfort. For example, in 2019, peak use of a hike–bike trail in the United States shifted from midmorning and early evening during the summer to one midday peak during the winter.¹⁷ Researchers also have predicted an overall net decrease in trail use by pedestrians and cyclists by 2050 due to global warming under intermediate and high greenhouse gas emission scenarios.¹⁷ When faced with high temperatures, US children have been shown to engage in less moderate to vigorous physical activity and to seek shade during school recess.^18,19 Furthermore, warming temperatures are projected to negatively impact recreational physical activities, such as skiing and snowboarding in winter seasons.²⁰ In Canada, Indigenous communities are disproportionately affected by climate change,^21,22 with their modes and routes of transportation and traditional land-based activities disrupted by warmer temperatures that melt ice roads (ie, frozen waterways) and increase the risk of flooding and fires that force evacuation from territorial homes.^23,24 The effects of climate change in Mexico, as discussed in more detail later, include higher temperatures and reduced rainfall, which will likely lead to similarly deleterious impacts on physical activity in other North American countries.²⁵

In Mexico, only 10 of the 182 protected natural areas have climate action programs.²⁶ One of the protected natural areas, Sierra de Guadalupe, is subject to fires, pollution, crime, irregular settlements, and social stigma that originate from lack of coordination on climate action policies. Climate action programs and other public policies, in contrast, are related to greater management capacity, cooperation, and power of local actors.²⁷ Pérez-Paredes and Sosa, who conducted their research during the COVID-19 pandemic, showed how a large coalition of environmental, sports, and cultural groups that shared the goal of conservation of the Sierra de Guadalupe used a citizen science approach^28,29 to keep the area clean and promote physical activity of the youth who use the protected natural areas via multiple physical activity events (eg, hiking tours).^30–32 Results from the Sierra de Guadalupe study demonstrate how concerted climate action can be used to promote youth physical activity.³³ Other examples of climate change and physical activity research in Mexico include findings by Wong et al³⁴ showing that a 1 °C increase in ambient temperature is associated with a 2-minute reduction in sedentary time for young children (4- to 6-y-olds) and findings by Wilson et al³⁵ showing that collection of physical activity data among children may be more difficult when using certain technologies (eg, Actiheart Activity monitor). However, there is currently limited research demonstrating how climate change is affecting physical activity in Mexico, and more research is needed.

Institutionalized discrimination affects physical activity opportunities for youth across North America. For example, during the COVID-19 pandemic, racial tensions in the United States reached a boiling point, illuminating longstanding social and political injustices rooted in institutionalized discrimination.^36,37 The murders of Ahmaud Arbery, George Floyd, Breonna Taylor, and other Black people in the United States have led to discussions about the connection between institutionalized discrimination, overt racism, and physical activity.^38,39 For example, Black people in the United States began voicing their fears and safety concerns in regard to being active in some settings (eg, running outdoors), modifying their exercise attire (eg, no hoodies), carrying identification while running, or ceasing to run outdoors altogether.^40–43 In Canada, Black and Indigenous people are 92% and 75%, respectively, more likely to report being discriminated against than are White individuals.⁴⁴ This experience of institutionalized discrimination begins in childhood as Indigenous youth report facing discrimination that negatively affects their resources and opportunities to engage in physical activity.⁴⁵ One example of discrimination in Mexico is that LGBTQ + youth report feeling more uncomfortable playing organized sports (ie, how) and are more worried about their teammates’ responses to a bad performance as compared with their non-LGBTQ+ peers.^45,46

Lee et al³⁹ discussed opportunities to promote physical activity in response to the increased recognition of institutionalized discrimination in the United States. They cited schools and early care and education centers as microsystems ideally suited for equitable physical activity promotion. Schools provide consistent physical activity opportunities to all youth, social support (eg, teacher encouragement), and behavioral prompts (eg, games) that are important for maintaining physical activity.^47,48 Furthermore, the US Community Preventive Services Task Force has identified school-based physical activity programs as an effective approach for decreasing a school’s prevalence of obesity.^49–51 Actionable strategies include offering multiple physical activity opportunities throughout the day (eg, before, during, and after school), engaging students in program development and delivery, using free physical activity resources (eg, brain breaks and Open Physical Education), and forming partnerships with local organizations that offer opportunities to promote physical activity (eg, Cooperative Extension and community centers). Some examples of school-based projects that engage the community include Sustainability via Active Garden Education,^52,53 the Coordinated Approach to Child Health,^49,54 and Strong Teens for Healthy Schools.⁵⁵ By using a community-engaged approach that includes students, school staff, and teachers throughout the process, these projects help to ensure that they are equitably providing physical activity for all youth. Furthermore, some of these projects consciously embed antidiscrimination elements. For example, Strong Teens for Healthy Schools requires schools to serve a high proportion of Black and Hispanic students (>40%) to be eligible to participate and then purposefully allows these students the freedom to choose their environmental change project (focused on physical activity or nutrition). Using this approach, Strong Teens for Healthy Schools elevates the voices of students that are often marginalized within their schools and society.

In March 2020, the World Health Organization declared COVID-19 a pandemic. Studies that examine the impact of the pandemic on youth have reported significant decreases in physical activity, matched by precipitous increases in sedentary behavior.^56–60 In one study, 36% of parents reported that the COVID-19 pandemic resulted in their children doing much less physical activity than during the same period a year before and that the settings of physical activity were also more likely to be in homes, garages, sidewalks, and roads.⁵⁹ Stay-at-home orders restricted physical activity to those with yards or walkable neighborhoods, and school closures eliminated recess and in-person physical education, shifting when physical activity occurred (ie, timing).^56,61,62 For example, one study found that the switch to online physical education, as opposed to in-person physical education, resulted in a 10-minute decrease in weekly physical education time.⁶³ Widespread moratoria on cultural gatherings, youth sports leagues, park activities, and recreation facilities, as well as cancelations of pay-for-use memberships, activities, and resources (eg, gyms and dance classes), limited physical activity opportunities.⁶¹ Closures of green spaces limited citizens’ use of these spaces for physical activity, affecting particularly lower income residents.⁶⁴ Furthermore, parks that remained open during the pandemic were observed to have lower use by children than before the pandemic.⁶⁵

Benji et al⁶² presented how the COVID-19 pandemic reduced some access to organized physical activity opportunities for Indigenous youth in Canada. On reserves, communities erected blockades to prevent people from entering or leaving.⁶⁶ The closing of schools and social programs, and the inability of individuals to leave their often overcrowded house, exacerbated unhealthy emotional and physical situations for many.⁶⁷ Some positive effects, however, did emerge: Communities connected virtually and delivered cultural programming online, and social media was used to share traditional dance.^67,68 Many Indigenous youths were able to spend more quality time with their families by engaging in traditional land-based practices, such as hunting, fishing, and gathering foods and medicines,⁶⁸ physical activity experiences that are vital to youth mental health and well-being.^69,70 Traditional land-based practices are one way to encourage physical activity of Indigenous youth; however, these lands are increasingly threatened by climate change.⁷⁰

As the aforementioned research demonstrates, forces of change can work synergistically and/or antagonistically with one another to affect youth physical activity. Thus, it is important to critically evaluate any solution that promotes physical activity in response to a force of change. For example, during the COVID-19 pandemic, technology emerged as a major medium for promoting physical activity.⁷¹ Youth in low-income households or rural locations, however, often did not have reliable access to technology, further exacerbating health inequities when physical activity programs were delivered online.⁷² Physical education also was less effective when delivered online as compared with in-person.⁷³ In such a situation, the use of online physical activity promotion tools exacerbated existing physical activity inequities for low-income and rural families. Thus, synergistic solutions, such as pairing online physical activity with policies that provide a tablet or laptop for every student, can help to improve physical activity. Together, these solutions address the need for physical distance during a pandemic and can help to reduce inequities through ensuring that all students have the tools that they need to participate.

As our aim was to highlight recent changes in youth physical activity that have resulted from 3 contemporary forces of change, we could not draw systematic inferences about consistencies or discrepancies between countries. However, some interesting similarities and differences did emerge. First, climate change appears to increase challenges to participating in and measuring physical activity across all 3 countries; however, studies from different countries show that increases in ambient temperature may have differential effects on activity outcomes (ie, reducing physical activity in the United States and reducing sedentary time in Mexico). Second, the increasing recognition of institutional discrimination in all 3 countries continues to highlight the negative impacts of discrimination on physical activity and many other health outcomes (eg, mental health). Although some research is beginning to embed antidiscrimination elements into physical activity programs, much more work is still needed for a variety of marginalized communities across all 3 countries. Finally, COVID-19 appeared to have a negative impact on physical activity across all 3 countries; however, it also promoted positive physical activity engagement within some communities (eg, engagement in traditional dance). More work is needed to identify opportunities to promote positive physical activity experiences in future public health crises.

Implementation science is the study of methods to promote the systematic uptake of evidence-based programs in practice.⁷⁶ Factors within individuals’ environment play a major role in their ability to use evidence-based physical activity programs. Thus, understanding the impact of forces of change on physical activity environments is necessary when using evidence-based programs for physical activity promotion.^77–80 Some useful implementation science tools include the US National Cancer Institute’s repository of evidence-based physical activity programs⁸¹; the Health Equity Implementation Framework⁸²; the expanded Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework⁸³; and organizational readiness assessments.^84,85 These tools take a multilevel approach to considering health equity and context when planning, implementing, and sustaining physical activity programs. They also can help to ensure that physical activity promotion initiatives are tailored for youths’ cultures, preferences, and needs.

Digital health is the use of information and communication technologies to promote wellness.⁸⁶ Websites, wearable physical activity devices, and smartphone apps are common types of digital health technologies that are used for youth physical activity promotion.⁸⁷ In 2019, nearly 95% of teenagers reported having access to smartphones, which have the potential to address environmental, space, time, and motivational barriers to physical activity.^88,89 Examples of how digital health technologies can address forces of change include the ability to reach people virtually during a pandemic, improving physical safety by providing real-time location data, and reducing climate-related barriers for youth.⁹⁰ Some digital health technologies (eg, wearables and apps) also allow for behavioral and contextual data to be continuously collected. For example, technological interventions that involve machine learning can be used to provide real-time, tailored guidance on how, where, and when youth are physically active. This wealth of dynamic data can be used to develop strategies that are tailored to an individual’s environment and provide real-time prompts to promote physical activity.⁹¹

CBPR is focused on social change that emphasizes partnerships leveraging the ingenuity of community knowledge and experience from promotion and practice with the scientific expertise of researchers.⁹² CBPR begins with a topic of importance to the community. It aims to combine knowledge with action and achieve social change to improve health outcomes and eliminate health disparities.^93,94 CBPR can be utilized to bring together multisectoral coalitions with different priorities, advocate for large-scale policy changes, and use Indigenous knowledge to improve the saliency of research and practice agendas. CBPR methods can engage youth in the program planning process, increasing interest in physical activity.^95,96 Engaging youth has many advantages, including enhanced buy-in, improved authenticity in the approach, and the development of programs that are tailored to the ways that youth prioritize for engaging in physical activity.^75–77 Initiatives that engage youth, and, in particular, underserved youth, are also needed to help address environments that impede youths’ participation in physical activity.⁹⁷

We offered 3 cross-disciplinary methodological research approaches that may be effective for enhancing youth physical activity promotion. Each approach, however, must be considered carefully to ensure it does not exacerbate existing health disparities. Here, we provide 3 additional considerations when promoting youth physical activity: