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Invited Commentary

Pediatric Inactivity Triad: A Risky PIT

Faigenbaum, Avery D. EdD, FACSM1; Rebullido, Tamara Rial PhD2; MacDonald, James P. MD, MPH, FACSM3

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Current Sports Medicine Reports: February 2018 - Volume 17 - Issue 2 - p 45-47
doi: 10.1249/JSR.0000000000000450
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A majority of children and adolescents worldwide are not accumulating at least 60 min of moderate to vigorous physical activity (MVPA) daily (1). Trends in measures of muscular fitness among youth are on the decline. Too many playgrounds and sports fields are vacant or idle, and physical education is considered an expendable part of the school curriculum. Consequently, contemporary youth are likely more familiar with controlling a joy stick than they are throwing a ball. This dreary litany is all too familiar.

The “product” of this culture — children who are weaker, slower, and heavier than their peers of yesteryear — is likewise becoming a more familiar site in pediatricians’ offices. Unsurprisingly, a corollary of these contemporary trends is the increasing prevalence of physical, psychosocial, and cognitive health issues in school-age youth (2). The World Health Organization now recognizes physical inactivity as the fourth leading risk factor for mortality from noncommunicable diseases, and the economic costs associated with physical inactivity among children are staggering (3,4).

The lasting effects of physical inactivity during childhood and adolescence can give rise to a lifetime of preventable pathology. The call for action to address this phenomenon has never been more urgent. Yet, we remain stuck in a mindset grounded in guidelines that focus almost solely on the achievement of at least 60 min MVPA each day. For years, the 60-min threshold has been seen as a benchmark (4); and over those years, the rising tide of physical inactivity has never ebbed.

It is said that “the definition of insanity is doing the same thing over and over again, and expecting different results.” A change in attitudes and pediatric health care practices is urgently needed because our current strategies are suboptimal. The time has come to expand our conceptual approach so we are better prepared to identify and treat youth who are physically inactive before they proceed too far down the path to chronic disease. In this commentary, we propose a tripartite framework of conditions that are collectively driving the pandemic of physical inactivity in youth, and we offer a novel conceptual approach to substantively address this public health crisis.

Pediatric Inactivity Triad

The pediatric inactivity triad (PIT) we propose is a condition observed in physically inactive youth involving three distinct but inter-related components: 1) exercise deficit disorder, 2) pediatric dynapenia, and 3) physical illiteracy. While each of these components in isolation is an important consideration, we argue they should be viewed collectively to better effect change. Pediatricians and researchers should adapt the practice of leaders in the field of sports injury prevention, who have begun to focus on a complex systems approach to most effectively address that phenomenon (5). Physical inactivity is a multifactorial phenomenon that is influenced by a web of contributing factors. We need to better understand these complex interactions and clarify how these interactions contribute to physical inactivity in children and adolescents. The Figure illustrates our current understanding of the interaction among the components of the PIT.

The PIT consists of three inter-related conditions that influence physical inactivity and related health risks.

The first component of the PIT relates to the construct called exercise deficit disorder, a term used to describe a condition characterized by levels of MVPA that are inconsistent with current public health recommendations (6). Instead of simply labeling a child as inactive, the term exercise deficit disorder should be used to highlight the gravity of this clinical condition, educate parents about the importance of daily MVPA, and prompt intervention on the part of pediatricians and other professionals. Youth who are not meeting minimal recommendations for MVPA would be identified as having a premorbid condition, and may then be treated with the same energy and resolve as a hypertensive child or a teenage smoker in order to prevent the progression of pathological processes.

Simply asking physically inactive boys and girls to “walk to school” or “play outside” is not enough. Structured and innovative therapeutic exercise programs are needed to target deficiencies, maintain participation, and promote healthy lifestyle choices for all youth found to have exercise deficit disorder, regardless of body size. Efforts that focus solely on obese youth will miss many at-risk children. The child who is found to have a deficit in MVPA levels but who currently has a body mass index (BMI) within normal limits has a premorbid condition and must be targeted for interventions as well.

Children and adolescents who lack prerequisite levels of muscular fitness and motor skill proficiency are less likely to be competent in sporting tasks (e.g., running, throwing, and so on) and may be expected to engage in less MVPA throughout the growing years. The second and third components of the PIT highlight the significance of identifying two other interrelated and treatable conditions which both affect and are affected by exercise deficit disorder.

The first phenomenon is pediatric dynapenia, a condition characterized by low levels of muscular strength and power and consequent functional limitations not caused by neurologic or muscular disease (7). A certain amount of muscular strength and power is needed to jump, climb, kick, and throw proficiently. Youth with low levels of muscular strength and power are more likely to remain inactive, experience functional limitations, and suffer activity-related injuries during free play and sport. These observations underscore the need to identify at-risk youth and target them for interventions designed to enhance muscular fitness. Improvements in strength and power will positively alter physical activity trajectories so inactive youth are able to break through a so-called strength barrier to catch up with their stronger peers. One need only to observe beginners in a gymnastics class or martial arts program to appreciate that prerequisite levels of muscular strength and power are needed to move with style, grace, and precision.

The third component of the PIT relates to the concept of physical illiteracy, which describes the lack of confidence, competence, motivation, and knowledge to move proficiently in a variety of physical activities. The term physical literacy has been broadly used to capture the attributes and characteristics that influence physical activity throughout the life course (8). The term physical illiteracy, we argue, incorporates the interrelated and negative influences of exercise deficit disorder and pediatric dynapenia, as seen in weak, inactive youth. Without requisite MVPA and muscular strength, children will be less apt to climb a playground structure or kick a ball. The less they engage in such play, the less fit they become and the less likely they are to experience the sheer joy of movement. Since the concept of physical illiteracy encompasses psychomotor, cognitive, and affective domains of learning, interventions need to be reinforced with effective pedagogical, motivational, and social strategies so inactive youth can learn the value of physical activity. The quantity of prescribed MVPA needs to be balanced with the quality of the movement experience (9).

A Paradigm Shift

Since positive and negative behaviors established during childhood tend to track into adulthood, we need to identify and treat physically inactive youth early in life to prevent the expected cardiometabolic, musculoskeletal, and psychosocial consequences later in life. Traditional interventions taken by pediatricians are currently triggered only after a child already has an elevated BMI or HgbA1c. We argue that the “horse is out of the barn” already if we wait for these signs to address at-risk youth.

This novel concept also will aid stakeholders in defining specific treatment goals. Traditional interventions tend to overlook the multifactorial, interconnected relationships between exercise deficit disorder, pediatric dynapenia, and physical illiteracy. Treatment strategies that only address one component of the PIT are less likely to result in desired outcomes. For example, walking programs that attempt to increase MVPA in youth but overlook the critical importance of enhancing neuromuscular fitness and improving physical literacy often have limited long-term benefit. Conversely, integrative exercise programs that include physical and cognitive training are more likely to improve health outcomes, enhance motor competence, boost fitness performance and reduce activity-related injuries in youth (10).

More than two millennia ago, the ancient Greeks and Romans argued that exercise was good for one’s health and well-being. However, Hippocrates and Galen did not have to contend with entertainment technology, the contemporary obesogenic physical environment, and a disease-focused health care system. The effects of physical inactivity on a child’s physical, psychosocial, and cognitive development are incontrovertible, but simply telling a child or a parent to embrace physical activity as our ancestors did has achieved next to nothing.

In this commentary, we have argued for the adaption of a new framework for addressing the epidemic of pediatric inactivity: the PIT, with its individual components. We believe that the proposed concept of PIT offers a new model that challenges our current approach and stimulates discussion, debate, and most especially, action on this pervasive public health issue. Concerted efforts from fitness professionals, health care providers, school administrators, public health officials, and others are needed to change social mores and common practice about physical inactivity. It is time that PIT, and its individual elements, enters the lexicon of all those concerned about the health of our children.

The authors thank Devon Mulrine for graphic art assistance with the figure.

The authors declare no conflict of interest and do not have any financial disclosures.


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