Policy and physical activity

Globally,physical inactivity is the 4th leading risk factor for mortality,following high blood pressure,tobacco use,and high blood glucose.1The benefits of physical activity(PA)in improving physical and psychosocial health have been well-documented.2However,one-third of adults and fourfifths of adolescents worldwide do not meet the minimum recommendations for PA,which imposes an immense burden on the health care system,given that 10% of all deaths from non-communicable diseases can be attributed to physical inactivity.3,4Unlike global progress in the areas of tobacco and alcohol control,strategies to address the high prevalence of physical inactivity and promote PA have lagged for multiple reasons(e.g.,biased perception and lack of institutional cooperation).Only recently have there been a coherent effort to address this problem,including surveillance,advocacy,and policy intervention.5Although research on the planning,implementation,and evaluation of PA policy is still immature,PA policy has widely been regarded as an essential part of the solution to global physical inactivity.

In response to the importance of and increasing interest in PA policy that addresses the epidemic of physical inactivity,theJournal of Sport and Health Science(JSHS)has brought together 3 articles in this special topic to provide an overview of scientific evidence on the effectiveness of PA policies on PA promotion.In this special topic,Chalkley and Milton review 4 fundamental PA policies in England,including national guidelines on PA,setting population goals and targets,surveillance and health-monitoring systems,and public education.They conclude that many improvements in national PA policies have been made that target children and young people.Establishing prevalence targets,streamlining surveillance systems,and investing in public education with supportive policies,environments,and opportunities are warranted in order to strengthen national policy efforts to increase PA and reduce sedentary behavior in England.Similarly,Woods et al.systematically review the evidence from 9 policy areas within the school setting that directly or indirectly influence PA outcomes.They conclude that the current evidence base supports the effectiveness of PA policy actions within the school setting but caution against a“one-size-fits-all”approach,stressing the need to examine policy implementation in order to maximize translation into practice.Finally,An et al.synthesize and quantify the relationship linking state laws governing school physical education(PE)to PE attendance and PA outcomes among students in the US.Students in states with strong PE laws were found to have an additional 0.2-day of PE attendance per week and spent an additional 33.9-min participating in PE classes per week.However,disparities in the implementation of state PE laws were found to exist across schools.Future studies are needed that use objective measures of PE and PA participation and that examine the roles that schools and districts play in mediating the effect of state PE laws on students’PE attendance and PA.

In sum,all 3 studies in this special topic demonstrate the potential of PA policy to positively impact people’s PA engagement,in particular among children and adolescents.These studies also reveal evidence-policy gaps and shed light on the possible barriers to implementing effective PA policy interventions,including low adoption rates,questionable sustainability,lack of unified terminology,lack of objective measures for PA and policy outcomes,and shortage of funds.

Despite the importance of policy design and implementation in population PA,2 popular but biased views may have hindered relevant research,practice,and the general public’s understanding of policy matters.First,policy impact is considered relatively small and less salient than the effect of smallscale intensive interventions.While,in general,that may hold,the comparison is an unfair one because the policy(e.g.,a physical activity education campaign)reaches a much larger population with a much smaller per-capita cost than those intensive interventions(e.g.,a month-long exercise camp for children with obesity).Therefore,cost-effectiveness or cost-benefit analysis should be the right tool to compare population policy with personalized interventions on an equal footing.Second,short-term evaluations of policy often reveal a lack of effect.Indeed,a policy effect usually takes a few years before a clear trend in the population can be observed.This is because the policy impact is often indirect,and changes in social norms and behavioral modifications are rather slow.It implies that a policy,once implemented,needs to retain consistency over an extended period,and a mid-to-long-term horizon should be adopted to evaluate the policy impact.

Addressing global physical inactivity is a public health priority.We hope this special topic ofJSHSstimulates future studies and contributes to the evidence base for PA policy as a key strategy in promoting and sustaining population-level PA.

Acknowledgment

Mengmeng Ji contributed to the preliminary drafting of this manuscript.

Competing interests

The author declares that he has no competing interests.

Ruopeng An,Guest Editor

Brown School,Washington University,St.Louis,MO 63130,USA

E-mail address:ruopeng@wustl.edu

Accepted 9 March 2021

Available online 17 March 2021