Regina Guthold,Juana Willumsen,Fiona Claire Bull

a Adolescent and Young Adult Health Unit,Maternal,Newborn,Child and Adolescent Health and Ageing Department,World Health Organization,Geneva CH-1211,Switzerland

b Physical Activity Unit,Health Promotion Department,World Health Organization,Geneva CH-1211,Switzerland

In most countries around the globe,adolescent girls are less physically active than boys. However, the majority of studies have been conducted in high-income countries, while there is less evidence from low-and middle-income countries.1The reasons for this gender difference in physical activity(PA)participation are poorly understood. A recently published article by Ricardo et al.2on gender inequalities in adolescent PA from 64 global south countries seeks to close this knowledge gap.

The health benefits of PA are well documented. For children and adolescents they include improved cardiorespiratory and muscular fitness, improved bone and cardiometabolic health,better cognitive outcomes, and reduced adiposity and symptoms of depression.3-5This evidence underpins the World Health Organization guidelines on PA and sedentary behavior.6-8They reaffirm the importance of regular PA of different types: First,young people aged 5-17 years should do at least an average of 60 min per day of moderate-to-vigorous intensity, mostly aerobic PA across the week. This includes active play and games, sports and exercise, physical education and active travel such as walking, wheeling, or cycling. Second, vigorous-intensity aerobic activities and those that strengthen muscle and bone should be incorporated on at least 3 days a week. Examples for vigorous-intensity activities are games with lots of running or team sports such as soccer,while muscle and bone strengthening activities include jumping, climbing, and lifting. Third,the amount of time spent being sedentary should be limited,particularly the amount of recreational screen time.6

Most global data on adolescent PA are on moderate-tovigorous intensity activity. A recent compilation from 146 countries showed that, on average, PA participation was 7 percentage points lower in girls than boys.1Similarly, girls appear to participate less in vigorous-intensity and in strengthening activities, though data are limited to mostly high-income countries.9,10In contrast, boys tend to engage more in sedentary behaviors such as watching TV, playing computer games,and recreational sitting generally.11

The recent paper by Ricardo et al.2confirms the gender difference in moderate-to-vigorous intensity activity for global south countries. Their investigation of both absolute and relative differences allows for detection of gender gaps in two ways and further raises awareness of an inequality issue that needs urgent attention.

What are the drivers of these persistent gender inequalities in adolescent PA? To answer this question, Ricardo and colleagues2chose to take a macro-level approach and assessed the influence of a number of country-specific factors on the adolescent PA gender gap. One of their key findings was that gender differences were greater in wealthier countries,as measured by the Human Development Index (HDI) (an indicator primarily including information on life expectancy, schooling and income), and by the gross domestic product. The authors offer a range of potential explanations for these findings. For example, the PA domains adolescent boys and girls engage in might be more similar in lower income countries (such as walking for transport)as compared to higher income countries,where recreation PA dominates and these opportunities might be more accessible for,and tailored towards boys.Consequently,to close the gender gap, wealthier countries should increase efforts to create more opportunities for girls.12Interestingly,studies in adults of the PA gender gap have found no consistent association with the HDI,13instead showing that within-country economic inequalities may be more important drivers of PA inequalities,especially in higher income countries.14

Ricardo et al.2also report that PA gender differences were smaller in countries with a higher Gender Inequality Index.This is surprising, given that the Gender Inequality Index includes measures of women’s reproductive health,empowerment and economic status, with a higher index indicating greater disparities between females and males.15A previous multi-country study (mostly of high-income countries) concluded that greater societal gender inequality was associated with a larger PA gender gap.16Again,it might be that,like the HDI, societal gender inequality could be a driver of the PA gender gap in higher income countries where PA is often a recreational choice with more options for boys, whereas, in lower income countries,societal gender inequality might result in girls doing more PA as part of household chores and/or for transport.We agree with Ricardo et al. that more research is needed to fully understand these associations, particularly regarding different types of adolescent PA in different settings.

Ricardo et al.’s macro-level approach to explaining gender differences in adolescent PA participation offers some new insights. However, physical inactivity is a “wicked” problem created and perpetuated by the complex system within which it occurs,17and as such, multiple levels need to be considered to explain participation.They include,besides societal factors,the transport system and environment, socio-cultural, political and individual factors. The strongest barriers to girl’s participation in PA may lie“closer”to the individual,such as the values and support of family and friends,perceptions of safety in the built environment, and opportunities to be active within school,including inclusive quality physical education.11

More research is needed to identify the barriers and facilitators of PA participation in girls, as well as their interaction, across diverse contexts and cultures. We need to understand better the gender differences in participation by the domains and types of PA,such as muscle and bone strengthening,and patterns of sedentary behaviors.11In doing so, the latest tools should be used,such as World Health Organization’s Global School-based Student Health Survey,18and the Global School Health Policies and Practices Survey19to assess school-level factors, for example.Questionnaire data should be complemented with device-based assessment of PA, including in low-income countries. Importantly,future studies must also include out-of-school adolescents,a group that has been largely neglected.

The PA gender gap is real and exists across age groups.20Much greater investment is needed to provide appropriate opportunities for everyone to be active from a young age and maintain activity.21Strategies to reduce gender differences should be embedded and prioritized in all of our efforts to increase PA levels in children and adolescents. The Global Action Plan on Physical Activity 2018-203022provides a menu of policy actions that are applicable and adaptable to all country contexts. A whole systems approach is required to achieve radical changes at social, environmental, and systems levels,through multidisciplinary and cross-sectorial collaboration to increase levels of PA in current and future generations.

Authors’contributions

RG has written the first and subsequent drafts of the article;JW and FCB have reviewed and commented on all drafts. All authors have conceptualized the article and agreed on its content.All authors have read and approved the final version,and agree with the order of presentation of the authors.

Competing interests

The authors are staff members at the World Health Organization. The authors alone are responsible for the views expressed in this publication and they do not necessarily represent the decisions,policy or views of the World Health Organization.The authors declare that they have no other competing interests.