Introduction

Mounting evidence suggests that childhood obesity may be associated with reduced physical functioning or ‘disability’ [1••] as defined by the WHO International classification of Functioning, Disability and Health (ICF). A recent umbrella review of 21 systematic reviews investigating 349 unique primary studies found ‘substantial impacts’ of childhood obesity on physical health that were most apparent as ICF impairments in body structures and function (e.g., neuromusculoskeletal impairment) [1••]. Positive cross-sectional association was evident between adiposity and musculoskeletal pain and musculoskeletal injury in children, whereas obesity inversely affected cardiorespiratory fitness, balance/coordination, general motor skills, functional mobility, and running speed/agility. Combined with an inverse association between adiposity and health-related quality of life, it becomes evident that carrying excess mass can have a significantly negative impact on a child’s ability to function, play, move, and engage in everyday life. Yet, these obesity-related impairments and complications are often not considered during clinical assessment, which could result in missteps when designing an effective personalized intervention plan or affect the child’s ability to adhere to the prescribed intervention.

Several high-quality systematic reviews have been published detailing the neuromusculoskeletal impairments observed in children and adolescents with obesity and the pathophysiological mechanisms involved. Building on these, this current report presents an overview of the impact of neuromusculoskeletal impairment and complications in children and adolescents with obesity and provides recommendations on how to translate the published evidence into clinical practice (e.g., short clinical encounters lasting 5–15 min).

What Are the Neuromusculoskeletal Impairments and Complications of Childhood Obesity?

Common neuromusculoskeletal impairments associated with childhood obesity are summarized in Table 1. The likelihood of increased musculoskeletal pain is particularly pertinent, with evidence suggesting that children with obesity may be at a greater risk of overall musculoskeletal pain, with specific complaints in the spine or lower limb [1••, 2–4]. Possible mechanisms are unclear, although biomechanical deviations, altered pain perception, or low-grade inflammation linked with obesity have been proposed [1••]. Reduced lower limb muscle strength have been widely reported when strength is corrected for body mass or when children with obesity perform tasks that require movement or propulsion of their mass, thus highlighting likely functional strength deficits [5•, 6–8]. Evidence is also emerging of impaired balance [1••, 7, 9], in children with obesity, speculated to be linked with sensory deficits and/or relative muscle weakness. Similarly, children with obesity demonstrate gait deviations, spinal/lower-limb postural malalignment, motor skill impairment, greater fatigue, or perceived exertion [10–12]. Evidence is less clear on the impact of childhood obesity on reduced flexibility and impaired bone health [7, 9, 13–18].

Table.1 Common neuromusculoskeletal impairments and complications of childhood obesity
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How Might Neuromusculoskeletal Impairments and Complications Affect the Life of the Child?

In addition to neuromusculoskeletal impairment there is also increasing evidence that children with obesity may have a reduced ability to undertake specific functional tasks or activities (i.e., ICF ‘activity limitations’) [1••, 23]. Common limitations identified include difficulty with functional mobility (walk, crawl, run), reduced running speed/agility, and emerging evidence of difficulties with climbing stairs and getting up from a chair [1••, 24–26]. Adiposity-related limitations in gross motor skills have also been widely reported (five systematic reviews) [1••], reflecting challenges with locomotor (e.g., jumping and hopping) and ball skills. Importantly, children with obesity perceive a lower level of health and fitness that can be mismatched to measured health outcomes [27]. These actual and perceived functional deficits combine to limit activity in children with obesity.

Children with obesity typically do not meet current recommended levels of moderate-vigorous physical activity; these levels are lower in comparison to leaner peers when examined using objective measures [28, 29]. Qualitative systematic/scoping reviews have explored common barriers to physical activity, indicating that children with obesity may be turned off activity by a range of ‘physical factors’ [12, 30]. Injury has been identified as a barrier to activity [12, 30] and a new meta-analysis of prospective evidence shows that youth with a higher BMI may be at a greater risk of injuring themselves during sport (OR 1.18) [31]. In addition, children with obesity have a higher risk of fractures [32]. Physical discomfort in the form of joint pain or shortness of breath and fatigue can prevent activity participation [12, 30]. Moreover, increased fatigue and higher rates of perceived exertion during weight-bearing activity may influence the type of activities that engage children with obesity [12, 10, 11]. Perceiving themselves to be less athletically capable can prevent children with obesity from participating in activity [12, 30]. Experiencing failure during physical activity was highlighted by youth as a factor contributing to their weight status, and low motivation to participate in activity or sport [12].

Motor skill competence has been cross-sectionally and prospectively linked with physical activity behaviors in children of varying weight status, supporting a possible ‘proficiency barrier’ [9, 22, 33, 34]. For instance, De Meester et al. [33] found that children with high motor skill competence were ~ 2.5 times more likely to achieve physical activity guidelines than those with low motor skill competence, although weight status was unknown in their sample. Another study reported that higher perceived/actual motor skill competence was predictive of more physical activity in 3rd- to 4th-grade children of all weight status [34]. Similarly, difficulties with running, hopping, walking, or ‘feeling clumsy’ were associated with lower sport participation in 7–14-year-olds with obesity [35]. More recently, evidence is emerging that slower development of fitness increases the risk of overweight and obesity [36] in children.

Participation in meaningful life situations may also be negatively impacted by obesity (i.e., ICF ‘participation restrictions’). Children with obesity consistently report impaired physical health-related quality of life (p-HRQOL) [37], suggesting that involvement in typical childhood life situations is adversely impacted (e.g., joining physical education class or a sports team or showering independently) [1••]. Tsiros et al. [24] found that higher adiposity in 10–13-year-olds was associated with less time spent in community participation activities, predominantly comprising of leisure/recreation (r − 0.23). Increasing participation in physical activity forms the foundation of obesity management and prevention [38]; activity interventions do have positive effects on health biomarkers including fundamental motor skill [39], muscle strength and performance [8], cardiometabolic and cardiorespiratory health, and body composition [40••]. Yet, meta-analytical evidence has shown that physical activity-promoting interventions have ‘no effect’ on overall physical activity in this population [41]. Thus, there are clearly limitations with current approaches to activity prescription for children with obesity. Instead, personalized interventions may be needed to address movement-related barriers to break a cycle of sub-optimal engagement in fun physical activity.

The ICF offers a theoretical framework for exploring such relationships, depicting complex, bidirectional interactions between body structure/function impairments, activity limitations, and participation restrictions [23]. For instance, it can be speculated that neuromusculoskeletal impairments such as pain, fatigue, reduced muscle strength, and fitness may mean that children with obesity do not have the necessary physical capabilities to participate in the typical physical activity and functional daily tasks expected of their peer group. A negative cycle of neuromusculoskeletal impairment, disability, lower physical competence, lower self-esteem, and reduced physical activity participation may ensue, further compounding weight status and associated functional deficits. Alternatively, physical fitness (comprising of strength, agility, and flexibility) was found to mediate the relationship between weight status and most HRQOL domains in children with overweight or obesity [42]. Both cardiorespiratory [42, 43] and muscular fitness (upper and lower limb) [42] have reported positive associations with physical wellbeing in children with obesity. Notably, these studies further suggest that negative associations between adiposity and physical wellbeing may be offset by muscular and/or cardiorespiratory fitness [42, 43]. Reduced lower extremity function (tests of single-leg balance and hop for distance) has also been associated with reduced p-HRQOL in children with obesity (explaining 48% variance) [44]. Evidence exploring such positive and negative links is beginning to emerge in the literature [9, 22, 33–35, 42–45]. Collectively, this emerging evidence suggests that certain obesity-related neuromusculoskeletal impairments and complications in ICF body function (e.g., single-leg balance, pain, bone strength, cardiorespiratory fitness, and physical fitness) may have negative links with physical wellbeing, which incorporates activities of daily living, play, and mobility as illustrated in Fig. 1. Moreover, restrictions in ICF activity (motor skills and isolated proficiency in running, hopping, walking) may be linked with lower physical activity and sport participation, increased injury, or impaired physical wellbeing. Thus, such factors may be potential assessment priorities when planning interventions for children and adolescents with obesity, although clearly more research is needed to confirm generalizability, causation, and probable bi-directional relationships. Thus, more quantitative research is needed to isolate the neuromusculoskeletal and movement-related factors that are likely to be most important in informing targeted interventions to enhance activity and participation in children with obesity.

Fig. 1
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Interactions between the components of the ICF model with a pediatric obesity example

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What Questions Can Illuminate Patient-Specific Challenges in Physical Function for the Child with Obesity?

Given the increased risk of neuromusculoskeletal impairment and subsequent activity limitation borne by children with obesity, it is essential that health professionals understand their role in screening, assessing, and addressing these complications (either through onward referral or direct treatment). Assessment should be conducted using open, respectful, and non-stigmatizing communication and a strength-based approach should value the existing knowledge, preferences, skills, and capacity of the child related to physical health, fitness, and participation. In the first instance screening questions (Table 2) can assist in triaging whether a child will require subsequent objective physical assessment, onward referral, or personalized intervention. Table 2 builds on previous suggestions for screening by the European Childhood Obesity Group [46] and can be a useful tool to those working in primary care to focus obesity assessment on outcomes other than body shape, size, or weight. Health professionals should listen carefully to how the parent and child respond to the questions throughout the clinical encounter. These questions should take no more than 5 mins. and thus, can easily be implemented into a standard wellness check. It should be noted that typical orthopedic variants occur throughout childhood development, and apophysites and osteochondroses are common causes of pain through adolescence [47, 48]. Therefore, health professionals should manage such conditions following current clinical recommendations [47, 48] and integrate into the overall obesity intervention. Health professionals should also be cognizant that movement difficulties may be impacted by additional obesity-related complications including impaired cardiorespiratory fitness, abdominal pain, hypertension, urinary incontinence, body consciousness or idiopathic intracranial hypertension and as such the neuromusculoskeletal assessment should be considered within the context of a holistic examination.

Table.2 Suggested questions addressing neuromusculoskeletal complications related to pediatric obesity
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For those treating children with severe pediatric obesity, a subsequent and more detailed clinical screening should be undertaken by health professionals who already have experience in treating physical impairment in children and adolescents with pediatric obesity and/or pediatric orthopedics. The screening questions described in Table 2 can be part of a more detailed physical examination using developmentally appropriate valid and reliable outcomes measures and tests. The type of outcome measure used will depend on the age of the child, the setting of the assessment and the availability of time and equipment. Figure 2 provides a non-exhaustive overview of the myriad tests used in assessing potential outcome measures of pediatric and adolescent neuromusculoskeletal health. Prior to undertaking neuromusculoskeletal assessment the need for, and procedures related to, the assessment should be clearly explained to the child and parent/s and appropriate consent obtained.

Fig. 2
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Non-exhaustive overview of the different tests that propose a reliable evaluation of each separate components and of the overall motor skill proficiency. *Thorough pain assessment required to elucidate type, frequency, location of pain plus aggravating/easing factors, and underlying cause of pain. BOT-2 Bruininks-Oseretsky Test of Motor Proficiency 2nd Edition, MABC-2 Movement Assessment Battery for Children 2nd Edition, Ped Pain Q PedsQL™ Pediatric Pain Questionnaire™, TGMD-3 Test of Gross Motor Development 3rd Edition, VAS visual analogue scale (100 mm), KTK Körperkoordinations Test für Kinder.

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How Do We Use the Knowledge Gained from Screening Questions and Objective Assessment to Develop an Appropriate Exercise Intervention?

Regardless of the physical capacity of the child or the existence of neuromusculoskeletal impairments, personalized physical activity and exercise interventions will be required as a cornerstone of obesity management. Similarly, the exercise intervention delivered as part of obesity management should be directed to address any observed neuromusculoskeletal impairments or complications (e.g., reduced strength) and improvement of such complications should be considered a successful outcome in obesity management. Table 3 describes some considerations and examples when designing exercise interventions for children and adolescents with obesity. The design of an appropriate exercise intervention will hinge on the findings of the physical assessment, the likelihood of impairments affecting engagement with treatment, and whether modifications to standard activity interventions may be required. The physical assessment will identify factors that should be addressed as part of holistic obesity management and will highlight the existence of red flags that should not be missed (e.g., night pain, multiple fractures, early morning joint stiffness, non-mechanical pain, unexplained muscle weakness/wasting, changes in sensation, regression of development, signs of slipped capital femoral epiphysis, skin alteration (bruising, psoriasis, café au lait), changes in bladder/bowel habit, concerns related to vision, speech or hearing). Health professionals may need to adapt or augment their ‘usual’ obesity exercise intervention to include non-weight bearing exercises, pacing techniques to address persistent pain or physical therapy modalities to treat specific impairments. For example, a child may present with medial knee pain that is exacerbated by loading during weight-bearing activity. In this example, it will be crucial to include the management of this pain as part of the obesity intervention to maximize engagement in physical activity and to support successful obesity management. The healthcare professional should clearly explain to patients and their parents that assessing and addressing neuromusculoskeletal impairments is important for supporting increased activity level and intensity as part of obesity treatment. Similarly, baseline assessment will support the health professional in commencing the fun activity intervention personalized to the child’s fitness level and preferences and taking into consideration any contraindications or precautions related to exercise. Thereafter a progressive program can be planned using collaborative goal setting and FITT-VP principles (frequency, intensity, time, type, volume, and progression) [49]. As the child progresses through treatment, monitoring of fatigue, pain, or other impairments identified during assessment should be undertaken and repeated measurement of baseline outcome measures can be integrated to evaluate how obesity treatment impacts physical fitness, function, and participation in tandem with measures of adiposity and cardiometabolic health. Given the increased risk of neuromusculoskeletal complications related to pediatric obesity, child-centered personalized treatment may also facilitate the prevention of musculoskeletal disease as the child grows (a leading cause of global disability) [50].

Table 3 Key considerations for exercise interventions in pediatric obesity management
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Conclusion

Children and adolescents with obesity have higher risk of neuromusculoskeletal impairment which may influence their engagement with obesity interventions and in turn influence the design of effective obesity interventions. Health professionals should screen for such impairment as part of standard clinical assessment. In this paper we provide tools to support how health professionals can assess, address, adapt, progress, monitor, and evaluate the impact of treatment on neuromusculoskeletal health in children with obesity.