Effects of pediatric obesity on joint kinematics and kinetics during 2 walking cadences

The Prevalence of Persistent Toe Walking in Children with and without Autism Spectrum Disorder and the Odds of Subsequent Surgery

Persistent toe walking is associated with autism spectrum disorder. The true prevalence of persistent toe walking and odds of progression to surgery in children with and without autism remains unclear. This retrospective descriptive study identified patients ages 3 - 17 years who were enrolled in our healthcare system over a two-year period. Using international classification of disease codes, we identified all children with autism and persistent toe walking, and excluded children with conditions that may independently cause toe walking. Data on Achilles lengthening surgeries, sex, race and body mass index was gathered. The toe walking prevalence amongst children with and without autism was calculated. Multivariable logistic regression analysis controlling for sex, race and body mass index was used to determine independent risk factors for persistent toe walking and surgery. Of the children who met inclusion criteria (N = 284,925), 4,622 (1.6%) had persistent toe walking. Prevalence of persistent toe walking was higher amongst children with autism (6.3% versus 1.5%, p < 0.01), as were odds of persistent toe walking (OR 4.13, 95% CI 3.74 - 4.56, p < 0.01). Males and White patients had higher odds of persistent toe walking compared to females and patients of any other race, respectively (p < 0.01 for all). Although children with autism and toe walking had higher rates of surgery than their counterparts without autism (4.3% versus 2.6%, p = 0.04), this difference was not significant after controlling for sex, race and BMI (OR 1.59, 95% CI 0.95 - 2.69, p > 0.05). LEVEL OF CLINICAL EVIDENCE: III.

The impact of pediatric obesity on biomechanical differences across the gait cycle at three walking speeds

BACKGROUND

Obesity impacts a child's ability to walk with resulting biomechanical adaptations; however, existing research has not comprehensively compared differences across the gait cycle. We examined differences in lower extremity biomechanics across the gait cycle between children with and without obesity at three walking speeds.

METHODS

Full gait cycles of age-matched children with obesity (N = 10; BMI: 25.7 ± 4.2 kg/m2) and without obesity (N = 10; BMI: 17.0 ± 1.9 kg/m2) were analyzed at slow, normal, and fast walking speeds. Main and interaction effects of group and speed across hip, knee, and ankle joint angles and moments in sagittal, frontal, and transverse planes were analyzed using one-dimensional statistical parametric mapping.

FINDINGS

Compared to children without obesity, children with obesity had greater hip adduction during mid-stance, while also producing greater hip extensor moments during early stance phase, abductor moments throughout most of stance, and hip external rotator moments during late stance. Children with obesity recorded greater knee flexor, knee extensor and knee internal rotator moments during early stance, and knee external rotator moments in late stance than children without obesity; children with obesity also demonstrated greater ankle plantarflexor moments throughout mid and late stance. Interaction effects existed within joint kinetics data; children with obesity produced greater hip extensor moments at initial contact and toe-off when walking at fast compared to normal walking speed.

INTERPRETATION

While few kinematic differences existed between the two groups, children with obesity exhibited greater moments at the hip, knee, and ankle during critical periods of controlling and stabilizing mass.

Body mass affects kinetic symmetry and inflammatory markers in adolescent knees during gait

BACKGROUND

Early-onset osteoarthritis has been attributed to pro-inflammatory factors and biomechanical changes in obesity. However, research has yet to explore whether knee joint moments are asymmetrical in children with obesity and could precede the onset of knee osteoarthritis. The present study compares knee moment asymmetry between adolescents with and without obesity and examines the relationship between asymmetries and inflammatory biomarkers.

METHODS

Twenty-eight adolescents (13-16 years) were classified as with (n = 12) or without (n = 16) obesity. Lower extremity kinetics were measured using three-dimensional motion analysis. Bilateral knee joint moments were analyzed in the sagittal, frontal, and transverse planes across stance phase. Kinetic asymmetry was calculated between the right and left sides and represented by the R2 value. Enzyme-linked immunosorbent assays analyzed serum 25-hydroxy vitamin D, interferon gamma, tumor nercrosis factor alpha, interleukin-6, and C-reactive protein levels. Parametric and non-parametric tests determined significant group differences in asymmetries and biomarkers, respectively. Spearman's correlations identified relationships between biomarkers and asymmetries with statistically significant group differences.

FINDINGS

Adolescents with obesity had greater sagittal (loading, midstance) and frontal (midstance, pre-swing) plane kinetic knee asymmetry and higher concentrations of interleukin-6 and C-reactive protein. A moderately negative correlation existed between C-reactive protein and sagittal (loading, midstance) plane asymmetry, and also between interleukin-6 and frontal (pre-swing) plane asymmetry.

INTERPRETATION

Inflammatory response increases with greater knee joint asymmetry, suggesting knee joint damage and altered joint loading co-exist in adolescents with obesity. Increased risk to joint health may exist in sub-phases where knee joints are improperly loaded.

Frontal plane knee moment in clinical gait analysis: A systematic review on the effect of kinematic gait changes

INTRODUCTION

The frontal plane knee moment (KAM1 and KAM2) derived from non-invasive three-dimensional gait analysis is a surrogate measure for knee joint load and of great interest in clinical and research settings. Many aspects can influence this measure either unintentionally or purposely in order to reduce the knee joint load to relieve symptoms and pain. All these aspects must be known when conducting a study or interpreting gait data for clinical decision-making.

METHODS

This systematic review was registered with PROSPERO (CRD42020187038). Pubmed and Web of Science were searched for peer-reviewed, original research articles in which unshod three-dimensional gait analysis was undertaken and KAM1 and KAM2 were included as an outcome variable. Two reviewers independently screened articles for inclusion, extracted data and performed a methodological quality assessment using Downs and Black checklist.

RESULTS

In total, 42 studies were included. Based on the independent variable investigated, these studies were divided into three groups: 1) gait modifications, 2) individual characteristics and 3) idiopathic orthopedic deformities. Among others, fast walking speeds (1) were found to increase KAM1; There were no sex-related differences (2) and genu valgum (3) reduces KAM1 and KAM2.

CONCLUSION

While consistent use of terminology and reporting of KAM is required for meta-analysis, this review indicates that gait modifications (speed, trunk lean, step width), individual characteristics (body weight, age) and idiopathic orthopedic deformities (femoral or tibial torsion, genu valgum/varum) influence KAM magnitudes during walking. These factors should be considered by researchers when designing studies (especially of longitudinal design) or by clinicians when interpreting data for surgical and therapeutic decision-making.

Biomechanical variations in children who are overweight and obese during high-impact activities: A systematic review and meta-analysis

Youth who are obese or overweight demonstrate evidence of poor lower extremity joint health and alterations in gait characteristics compared with youth who are healthy weight. However, there is no consensus if altered movement patterns are still present during high-impact activities. The purpose of this review was to determine if spatiotemporal and kinematic and kinetic variables during high-impact activities were significantly different between youth who are overweight and obese compared with youth who are healthy weight. An electronic search of five databases was conducted, and a meta-analysis and qualitative evidence synthesis was performed to determine the level of evidence, analyzing three tasks: running, jumping, and hopping. The findings of this review include the following: (1) overweight/obese (OW/OB) had higher stance phase time during running, (2) OW/OB had decreased hip flexion angles during running and stationary running, (3) OW/OB had decreased knee flexion angles during landing phase of jumping and hopping, and (4) OW/OB had increased hip abduction moments during running and jumping. These altered kinematic and kinetic variables at the hip and knee may result in mechanical inefficiency with high-impact activities, as well as potentially increased risk of joint degradation and poor joint health into adulthood.

Effects of Overweight and Obesity on Running Mechanics in Children

PURPOSE

The purpose of this study is to determine differences in running mechanics between healthy weight (HW) children and children classified as OW/OB.

METHODS

Forty-two children (17 OW/OB, 25 HW) ran overground while kinematic and kinetic data were recorded using a motion capture system and force plate. Kinematic variables of interest included stance time, step length, and frontal and sagittal plane joint angles and excursions at the hip, knee, and ankle. Kinetic variables of interest included ground reaction forces and hip, knee, and ankle moments in the sagittal and frontal planes.

RESULTS

The OW/OB group spent more time in stance, took shorter steps, displayed less hip flexion during the first half of stance, had greater ankle inversion at foot strike, had greater knee abduction throughout stance, and had smaller knee flexion, knee adduction, and hip adduction excursions. In comparing unscaled ground reaction forces, the OW/OB group displayed greater peak vertical force, vertical impact peaks, and vertical loading rates. The OW/OB group also displayed greater unscaled plantar and dorsiflexion moments, knee flexion and extension moments, ankle inversion moments, and knee and hip abduction moments.

CONCLUSION

These data suggest that increased body weight in children is associated with changes in running mechanics. Higher joint moments and ground reaction forces may indicate increased injury risk or the development of joint degeneration among overweight/obese children.

The effects of adiposity, muscular strength, cardiorespiratory fitness, and fatigue on gait biomechanics in overweight and obese children

BACKGROUND

Obesity rates continue to increase in the child population. Muscular strength, cardiorespiratory fitness, and fatigue can potentially affect joint stresses in obese children. The purposes are to examine: (1) the relationship between cardiorespiratory fitness and the change in joint stress pre- to post-fatigue; (2) the predictive value of fitness, adiposity, and muscular strength on joint stresses in fatigued and non-fatigued states; and, (3) the relationships between % body fat from skinfold and air displacement plethysmography.

METHODS

Twenty-seven children, with body mass index above the 85th percentile for their age participated in this study. Lower limb joint moments were recorded before and after a fatiguing Progressive Aerobic Cardiovascular Endurance Run protocol. Linear regression was used to assess the relationship between (1) fitness and change in joint stress pre- to post-fatigue, and (2) measures of %body fat using skinfold and plethysmography. Furthermore, Bland-Altman analysis quantified the agreement between measured adiposity using the two methods.

FINDINGS

The strongest relationship was observed between fitness and the change in the knee extensor moment pre- to post-fatigue (R² = 0.24). Regardless of fatigue state, adiposity and strength were identified as the strongest predictors of joint moments. Skinfold estimates were moderately predictive (R² = 0.56) of %body fat from air displacement plethysmography, and these two measures demonstrated instrument agreement with no proportional bias.

INTERPRETATION

Fitness level is not related to changes in biomechanics pre- to post-fatigue in overweight and obese children. Adiposity and lower extremity strength most strongly influenced joint moments in the frontal and sagittal planes.

The effect of body weight on joint torques in teenagers: Investigation of sit-to-stand movement

BACKGROUND

Obesity is becoming more common in the world. This causes various health problems, especially musculoskeletal disorders. Previous studies have examined the kinematic effects of increasing weight on joints. However, the mechanical effects of movement patterns have not yet been described. The aim of this study was to investigate joint torques in sit-to-stand movement in teenagers with a range of body mass indices (BMI).

METHODS

20 participants (12-17 years old) participated the study. They were divided into 4 groups according to BMI. Participants performed sit-to-stand movements and the video was captured. Angular displacement, angular velocity, and angular acceleration were calculated for each joint. A four-degree-of-freedom link-segment model was created for a dynamic analysis of sit-to-stand. Joint torques were calculated using the inverse dynamic method.

FINDINGS

Overweight increases joint torques in hips, knees, and ankles. In obese participants with a BMI 36% higher than normal-weight participants, joint torques in hips, knees, and ankles were higher by 46, 48, and 33%, respectively. In underweight participants with a BMI 21% lower than normal-weight participants, joint torques in neck, hip, knee, and ankle were lower by 20, 30, 17, and 7%, respectively.

INTERPRETATION

Overweight participants have a different sit-to-stand movement pattern. Movement differences and overweight may cause an overload on joints.

Influence of loading direction due to physical activity on proximal femoral growth tendency

Longitudinal bone growth is regulated by mechanical forces arising from physical activity, whose directions and magnitudes depend on activity kinematics and intensity. This study aims to investigate the influence of common physical activities on proximal femoral morphological tendency due to growth at the femoral head growth plate. A subject-specific femur model based on magnetic resonance images of one able-bodied 6-year old child was developed, and the directions of hip contact force were described as load samples at a constant magnitude. Finite element analysis was performed to predict growth rate and growth direction, and expected changes in neck-shaft angle and femoral anteversion were computed corresponding to circa 4 months of growth. For most loading conditions, neck-shaft angle and femoral anteversion decreased during growth, corresponding to the femur's natural course during normal growth. The largest reduction in neck-shaft angle and femoral anteversion was approximately 0.25° and 0.15°. Our results suggest that most common physical activities induce the expected morphological changes in normal growth in able-bodied children. Understanding the influence of contact forces during less common activities on proximal femoral development might provide improved guidelines and treatment planning for children who have or are at risk of developing a femoral deformity.

Does schoolbag carriage equally affect obese/overweight and healthy-weight children?

Discrepancies exist in backpack load recommendations for obese/overweight children, and the recommendations do not consider school trolleys. This study analysed obese/overweight and healthy-weight students' perceived load and fatigue when carrying schoolbags and their gait kinematics and rate of perceived exertion (RPE) when carrying backpacks or pulling school trolleys with different loads. Twelve obese/overweight and 36 healthy-weight students were asked about their perceived load and fatigue in carrying their schoolbags to school. Then, a kinematic gait analysis was completed in students walking unloaded or transporting 10%, 15% or 20% of their bodyweight (BW) in a backpack or trolley. RPE was recorded after each condition. The average hip rotation and knee adduction angles differed between body mass index (BMI) groups. The healthy-weight group reported higher RPEs than the overweight/obese group when pulling a trolley with 10-15% BW. In conclusion, both BMI groups responded similarly to load and schoolbag type.

Geometric and Mechanical Bone Response to a Multidisciplinary Weight Loss Intervention in Adolescents With Obesity: The ADIBOX Study

The effectiveness of structured multidisciplinary weight loss (WL) programs combining nutrition and physical activity on bone geometry and strength remains uncertain in adolescents with obesity. The study investigated the impact of a structured WL intervention on bone geometry and strength in adolescents with obesity. Thirty-one adolescents with obesity (mean [standard deviation] 13.61 [1.27] yr, body mass index Z-score 2.26 [0.30]) experienced an 8-mo WL program. A group of 23 maturation-matched controls (mean [standard deviation] 15.90 [0.43] yr, body mass index Z-score -0.12 [0.48]) were recruited for calculating Z-scores. Body composition, bone density, geometry, and mechanical properties were assessed using dual-energy X-ray absorptiometry and dual-energy X-ray absorptiometry-derived hip structural analysis. Plasma concentration of leptin, estradiol, collagen type 1 cross-linked C-telopeptide (CTx), and procollagen type 1 N-terminal propeptide were measured. Longitudinal analysis showed that adolescents with obesity reduced body weight and fat mass (total [g, %; p < 0.007]). After 8 mo, body mineral density at total body less head (Δ 3.22 [3.58] % p < 0.001) and lumbar spine (Δ 3.67 [4.04] % p < 0.001) increased. At the narrow neck (NN) of the femur, lower body mineral density (Δ -7.19 [8.79] % p < 0.001) and higher endocortical diameter and width were observed (NN endocortical diameter Δ 2.85 [0.26] %, NN width Δ 5.48 [10.84] %, respectively). An increased buckling ratio (Δ 8.24 [2.00] % p = 0.005) was also evident. Similar concentration of procollagen type 1 N-terminal propeptide and CTx was seen from baseline to 8 mo. However, at 4 mo, lower CTx levels were observed. The 8-mo WL program was associated with some positive adaptations among bone density parameters for the whole body and spine. However, bone geometry and strength estimates appeared to weaken at the NN. Clinically, the buckling ratio score at the NN was close to the fracture threshold. An "androgynous-like" adaptation was observed with bone geometry changes demonstrating periosteal expansion and endocortical resorption.

The effects of pediatric obesity on patellofemoral joint contact force during walking

BACKGROUND

Obesity increases a child's risk of developing knee pain across the lifespan, potentially through elevated patellofemoral joint loads that occur during habitual weight-bearing activities.

RESEARCH QUESTION

Do obese children have greater absolute and patellar-area-normalized patellofemoral joint forces compared to healthy weight children during walking?

METHODS

We utilized a cross-sectional design to address the aims of this study. Experimental biomechanics data were collected during treadmill walking in 10 healthy-weight and 10 obese 8-12 year-olds. We used radiographic images to develop subject-specific musculoskeletal models, generated walking simulations from the experimental data, and predicted patellofemoral joint contact force using established techniques.

RESULTS

We found that the obese children had 1.98 times greater absolute (p = 0.002) and 1.81 times greater patellar-area-normalized (p = 0.008) patellofemoral joint contact forces compared to the healthy-weight children. We observed a stronger relationship between absolute patellofemoral joint contact force and BMI (r²=0.58) than between patellofemoral joint contact force and body fat percentage (r²=0.38).

SIGNIFICANCE

Our results indicate that obese children walk with increased patellofemoral loads in absolute terms and also relative to the area of the articulating surfaces, which likely contributes to the increased risk of knee pain in this pediatric population. This information, which provides a baseline comparison for future longitudinal studies, also informs the type and frequency of physical activity prescription aimed at reducing the risk of knee injury and improving long-term outcomes.

Kinematic Comparison of Aquatic- and Land-Based Stationary Exercises in Overweight and Normal Weight Children

PURPOSE

This study examined lower extremity kinematics in healthy weight (HW) and overweight (OW) children during water- and land-based stationary exercises (stationary running, frontal kick, and butt kick) at light submaximal intensity.

METHODS

Participants included OW (N = 10; body fat percentage: 34.97 [8.60]) and HW (N = 15; body fat percentage: 18.33 [4.87]) children, aged 10 to 13 years. Spatiotemporal data, lower extremity joint kinematics, and rating of perceived exertion (RPE) were collected during water- and land-based stationary exercises. Repeated measures analysis of variance compared kinematic variables and RPE between groups and environments. A polygon area function compared coordination patterns between environments.

RESULTS

RPE responses were significantly greater in OW than HW children on land (13.6 [0.7] vs 11.6 [0.7]; P < .001), whereas the RPE responses were similar between groups in water (11.2 [0.7] vs 11.1 [0.8]; P > .05). OW children were significantly more upright than HW children during land-based exercise, whereas there were no differences observed between groups during aquatic-based exercise. The duration of stance and swing phases, angular velocity, and cadence were significantly lower in water than on land.

CONCLUSION

Compared with HW children, OW children performed stationary exercises in a more upright posture on land, with higher RPE. However, these differences diminished in water. Aquatic-based exercise may be effective in minimizing the effects of excess mass on OW children's ability to complete physical activity.

A systematic review on biomechanical characteristics of walking in children and adolescents with overweight/obesity: Possible implications for the development of musculoskeletal disorders

It is known that obesity is associated with biomechanical alterations during locomotor tasks, which is considered a potential risk factor for the development of musculoskeletal disorders (MSKD). However, the association of obesity with biomechanical alterations of walking in the early stages of life have not yet been systematically reviewed. Thus, this review aims to summarize the biomechanical characteristics of walking in children and adolescents with overweight/obesity (OW/OB) versus their normal-weight (NW) counterparts. PubMed and Web of Science were systematically searched until November 2018. We found strong and moderate evidence supporting biomechanical differences in the gait pattern of OW/OB with respect to NW. Based on strong evidence, the gait patterns of OW/OB present greater pelvis transversal plane motion, higher hip internal rotation, higher hip flexion, extension and abduction moments and power generation/absorption, greater knee abduction/adduction motion, and higher knee abduction/adduction moments and power generation/absorption. Based on moderate evidence, OW/OB walk with greater step width, longer stance phase, higher tibiofemoral contact forces, higher ankle plantarflexion moments and power generation, and greater gastrocnemius and soleus activation/forces. These biomechanical alterations during walking in OW/OB could play a major role in the onset and progression of MSKD.

Effects of a lower extremity exercise program on gait biomechanics and clinical outcomes in children and adolescents with obesity: A randomized controlled trial

BACKGROUND

Research highlights the detrimental effects of obesity on gait biomechanics and the accompanied risk of lower-extremity skeletal malalignments, increased joint stress, pain and discomfort. Individuals with obesity typically show increased knee valgus angles combined with an increased step width. Accompanying muscular dysfunctions impede their ability to compensate for these alterations, especially in the frontal plane. To date, no studies are available, which evaluated the potential effects of an exercise program (EP) in reducing these unfavorable biomechanical changes.

RESEARCH QUESTIONS

Is a 12-week EP, which includes hip abductor and knee extensor strength exercises and fosters dynamic knee alignment, effective in positively altering gait biomechanics in children and adolescents with obesity?

METHODS

This study was a randomized controlled trial having children and adolescents with obesity assigned to an EP (n = 19) or control (n = 16) group. Pain, self-rated knee function, muscle strength and 3D gait analysis during walking and stair climbing were evaluated.

RESULTS

Results indicate that the EP was able to increase muscular strength especially in the hip abductors. In addition, children from the EP group walked with less maximum hip adduction and reduced pelvic drop during weight acceptance at follow-up. No changes were present in self-rated knee function, pain or discomfort.

SIGNIFICANCE

Even though effects were small, results indicate that an EP is an effective short-term possibility to counteract the progressive development of biomechanical malalignments of the lower extremity. Clinical parameters indicated that the program was feasible. Nonetheless, low adherence highlights the need to develop more attractive programs. CLINICAL TRIALS REG. NO: clinicaltrials.gov (NCT02545764).

Blount disease

Blount disease is an asymmetrical disorder of proximal tibial growth that produces a three-dimensional deformity. Tibia vara is the main component of the deformity. Blount disease exists as two clinical variants, infantile or early-onset, and adolescent or late-onset, defined based on whether the first manifestations develop before or after 10 years of age. The pathophysiological mechanisms are unclear. In the Americas and Caribbean, Blount disease chiefly affects black obese children. Without treatment, the prognosis is often severe, particularly in the infantile form due to the development of medial tibial epiphysiodesis at about 6 to 8 years of age. In other parts of the world, the associations with black ethnicity and obesity are less obvious and the prognosis is often less severe. A consensus exists about the optimal treatment in two situations: before 4 years of age, progressive Blount disease should be corrected, preferably by a simple osteotomy; and once medial tibial epiphysiodesis has developed, both a complementary epiphysiodesis and gradual external fixator correction of the other alignment abnormalities, rotational deformity, and limb length are required. After 4 years of age, the outcome in the individual patient is difficult to predict. Magnetic resonance imaging supplies information on the morphology and vascularisation of the growth regions, thereby helping to guide treatment decisions. In the adolescent form, morbid obesity limits the treatment options. Untreated Blount disease in adults is rarely encountered. A more common occurrence is the presence of residual abnormalities at skeletal maturity in patients treated for Blount disease in childhood. Premature osteoarthritis may develop. In this situation, osteotomy may delay the need for total knee arthroplasty.

Stationary Exercise in Overweight and Normal Weight Children

PURPOSE

This study examined differences in lower extremity kinematics and muscle activation patterns between normal weight (NW) and overweight (OW) children during stationary exercises (running in place, frontal kick, and butt kick) at submaximal intensity.

METHODS

Healthy children (aged 10-13 y) were stratified into OW (n = 10; body fat percentage: 34.97 [8.60]) and NW (n = 15; body fat percentage: 18.33 [4.87]). Electromyography was recorded for rectus femoris, vastus lateralis, biceps femoris, gastrocnemius, and tibialis anterior. In addition, the ratings of perceived exertion and range of motion of hip, knee, and ankle joints were collected during stationary exercises. Repeated-measures analysis of variance compared muscle activation, range of motion, and ratings of perceived exertion between groups and exercises. Friedman test examined sequencing of muscles recruitment.

RESULTS

Compared with NW, OW experienced significantly greater ratings of perceived exertion (13.7 [0.8] vs 11.7 [0.7]; P < .001) and electromyography amplitude in all muscles apart from vastus lateralis during stationary exercises. In addition, NW children used more consistent muscles' recruitment pattern in comparison with OW children. The range of motion was similar between groups at all joints.

CONCLUSION

OW children may adopt a more active neuromuscular strategy to provide greater stability and propulsion during stationary exercises. Stationary exercise can be prescribed to strengthen lower extremity muscles in OW children, but mode and intensity must be considered.

Gait changes after weight loss on adolescent with severe obesity after sleeve gastrectomy

BACKGROUND

It has been highlighted that obesity influences the gait reducing walking velocity, stride length, ankle dorsal flexion at initial contact and ankle power generation. Meanwhile, step width, double support, hip flexion, knee extension during stance, hip moment and ankle power absorption was described increased. A tendency to the normalization of these parameters occur when subjects reduced their weight during growth.

OBJECTIVE

We studied the effect of fast weight loss due to Sleeve Gastrectomy on gait pattern of adolescent with severe obesity. The aim is to assess the functional benefit of the surgery.

SETTING

Pediatric hospital, public health, Italy.

METHODS

11 patients before and after 1 year from surgery and 10 controls participated to the study. We studied the gait with an optoelectronic system and two force plates. We evaluated both kinetics and kinematics of walking. Then we looked at the differences between the pre- vs post-surgery and with the control group.

RESULTS

Step length and velocity were lower and step width was bigger in adolescent with obesity. Kinematic and kinetic parameters were altered. After surgery we observed the reduction of several gait alteration. Meanwhile, after 1 year alterations at the level of the foot, the knee and the pelvis persist.

CONCLUSION

The sudden loss of weight highlighted the presence of long-term effects on the locomotor system. The results discourage intense walking activities before the weight loss and we suggest further studies for evaluating the necessity of a rehabilitative intervention.

Gait Pattern, Impact to the Skeleton and Postural Balance in Overweight and Obese Children: A Review

The article reviews the biomechanical factors that may cause overweight/obese children to reduce their level of physical activity, while increasing their risk of overuse injuries and exercise-related pain. Recommendations would be to screen those children for any gait or postural impairments before they join any exercise program, and to provide them with specific gait treatments and/or physical exercise programs, in order to decrease their risk for future musculoskeletal injuries and pain.

A Pilot Study of Iyengar Yoga for Pediatric Obesity: Effects on Gait and Emotional Functioning

Obesity negatively impacts the kinematics and kinetics of the lower extremities in children and adolescents. Although yoga has the potential to provide several distinct benefits for children with obesity, this is the first study to examine the benefits of yoga for gait (primary outcome) in youths with obesity. Secondary outcomes included health-related quality of life (HRQoL), physical activity, and pain. Feasibility and acceptability were also assessed. Nine youths (11⁻17 years) participated in an eight-week Iyengar yoga intervention (bi-weekly 1-h classes). Gait, HRQOL (self and parent-proxy reports), and physical activity were assessed at baseline and post-yoga. Pain was self-reported at the beginning of each class. Significant improvements were found in multiple gait parameters, including hip, knee, and ankle motion and moments. Self-reported and parent-proxy reports of emotional functioning significantly improved. Time spent in physical activity and weight did not change. This study demonstrates that a relatively brief, non-invasive Iyengar yoga intervention can result in improved malalignment of the lower extremities during ambulation, as well as in clinically meaningful improvements in emotional functioning. This study extends current evidence that supports a role for yoga in pediatric obesity.

Biomechanical characteristics of lower limb gait waveforms: Associations with body fat in children

BACKGROUND

Childhood obesity is associated with musculoskeletal dysfunction and altered lower limb biomechanics during gait. Few previous studies have explored relationships between childhood obesity measured by body fat and lower limb joint waveform kinematics and kinetics.

RESEARCH QUESTION

What is the association between body fat and hip, knee and ankle joint angles and moments during gait and in 7 to 11 year-old boys?

METHODS

Fifty-five boys participated in the study. Body fat was measured by air displacement plethysmography. Hip, knee and ankle 3D waveforms of joint angles and moments were recorded during gait. Principle component analysis was used to reduce the multidimensional nature of the waveform into components representing parts of the gait cycle. Multiple linear regression analysis determined the association between the components with body fat.

RESULTS

Higher body fat predicted greater hip flexion, knee flexion and knee internal rotation during late stance and greater ankle external rotation in late swing/early stance. Greater hip flexion and adduction moments were found in early stance with higher body fat. In mid-stance, greater knee adduction moments were associated with high body fat. Finally, at the ankle, higher body fat was predictive of greater internal rotation moments.

SIGNIFICANCE

The study presents novel information on relationships between body fat and kinematic and kinetic waveform analysis of paediatric gait. The findings suggest altered lower limb joint kinematics and kinetics with high body fat in young boys. The findings may help to inform research in to preventing musculoskeletal comorbidities and promoting weight management.

Variation inflation factor-based regression modeling of anthropometric measures and temporal-spatial performance: Modeling approach and implications for clinical utility

BACKGROUND

Understanding the relationship of underlying anthropometry to temporal-spatial performance is critical to appropriate assessment of patients with ambulatory dysfunction. The current body of literature has established the importance of limb length in this relationship. This study sought to re-examine these relationships in light of recent trends in body habitus and obesity, using Variation Inflation Factor analysis to optimize the model.

METHODS

Elementary school children (n=452; ages 5-13) were tested during walking at a self-selected speed across an instrumented walkway. Temporal-spatial and anthropometric measures were compiled for all children. The relationship between temporal-spatial and anthropometric measures was assessed using regression modeling with Variation Inflation Factor optimization.

FINDINGS

Body weight was identified as a significant predictor of cycle duration, stride length, stance duration, and step width during initial modeling. However, it did not meet the constraints imposed during Variation Inflation Factor optimization and was removed from the final models. The final optimized models identified significant relationships between both temporal-spatial parameters of interest and other temporal-spatial measures, with the best fit identified for walking speed (R²=0.6148).

INTERPRETATION

The use of the Variation Inflation Factor constraint during the regression modeling process ensured final models composed of truly independent predictor variables. The resulting models are highly robust and highlight the complex relationships between body structure, functional conditions, and walking performance. These models have value for routine clinical assessment of ambulatory dysfunction, and may provide a foundation for classifying temporal-spatial performance in the context of multiple contributing parameters.

Effects of a Program for Improving Biomechanical Characteristics During Walking and Running in Children Who Are Obese

PURPOSE

To investigate the influence of a weight-reduction program with locomotion-emphasis on improving biomechanical characteristics of children who are obese (OW).

METHODS

Ten children who are OW participated in a 6-month multidisciplinary childhood obesity management program (GRP1); another 10 children who are OW participated in the same multidisciplinary childhood obesity management program with additional locomotion-emphasis exercises for improving biomechanical characteristics (GRP2); and 10 control children who are OW with no intervention program. Outcomes were anthropometric measurements and temporal and foot pressure parameters.

RESULTS

GRP2 had significantly improved foot pressure in the different walking/running speeds compared with GRP1. In the temporal parameters, pretests by speed by group interactions were significantly improved for GRP2 compared with GRP1.

CONCLUSIONS

We found evidence to support beneficial effects of combined dietary and physical activity/locomotion-emphasis exercises on the movement characteristics of children who are OW.

Relationships Between Standing Frontal-Plane Knee Alignment and Dynamic Knee Joint Loading During Walking and Jogging in Youth Who Are Obese

BACKGROUND

Youth who are obese have high risk of poor knee health and cartilage damage. Understanding factors which may affect knee health in youth who are obese is critical for preservation of knee integrity and function.

OBJECTIVE

This study compared standing frontal-plane knee alignment and knee loading patterns between youth who are obese and those of healthy weight and determine the association between knee alignment and knee loading patterns during walking and jogging.

DESIGN

This study used a cross-sectional matched pair design.

METHODS

Twenty youth who were obese and 20 youth who were healthy-weight (ages 11-18 years) were recruited. Three-dimensional motion analysis quantified standing frontal-plane knee alignment as well as frontal- and sagittal-plane knee moments during walking and jogging. Paired t -tests, multiple analysis of covariance, and Spearman's rank correlation coefficients were used for analysis.

RESULTS

The youth who were obese demonstrated greater knee valgus in standing ( P  = 0.02), lower normalized peak external knee adduction moments during walking ( P  = 0.003), and greater normalized peak external knee extension moments during jogging ( P  = 0.003) compared with the youth who were healthy-weight. Standing knee alignment did not correlate with knee moments in the youth who were obese.

LIMITATIONS

Results are limited to small, homogeneous cohorts. The standing alignment methodology is not validated in this population and may limit interpretation of results.

CONCLUSION

Youth who are obese stand in more knee valgus and have altered knee loading patterns during walking and jogging compared with youth who are healthy-weight. Frontal-plane knee alignment does not correlate with frontal-plane knee loading patterns in youth who are obese. A better understanding of other mechanisms related to joint loading in youth who are obese is necessary to maintain long-term joint integrity in this population.

Do fitness and fatigue affect gait biomechanics in overweight and obese children?

The purpose of this study was to determine how an overweight or obese child's cardiorespiratory fitness level and a state of fatigue affect gait biomechanics.

METHODS

Using a three-dimensional motion analysis system, twenty-nine (female and male) overweight and obese children aged 8-11 years walked on force plates before and after being fatigued from the Progressive Aerobic Cardiovascular Endurance Run (PACER) protocol. Joint moments were calculated for the knee and hip in the frontal and sagittal planes.

RESULTS

In a non-fatigued state, peak hip and knee adductor moments showed a negative relationship with cardiorespiratory fitness level (R²=0.26, 0.26). After the subjects were fatigued, peak hip extensor (p=0.02), peak knee extensor moments (p=0.02) and peak knee adductor moments (p=0.01) showed a significant increase.

CONCLUSION

This trend illustrates that as an overweight or obese individual's fitness improves, the lower limb joint moments in the frontal plane decrease when walking. However, with the introduction of cardiorespiratory fatigue, lower limb joint moments tend to increase in the frontal and sagittal planes. Increased joint stress may have potential implications for obese children performing physical activity, as well as for clinicians who are attempting to intervene in the cycle of obesity.

A principal component analysis approach to correcting the knee flexion axis during gait

Accurate and precise knee flexion axis identification is critical for prescribing and assessing tibial and femoral derotation osteotomies, but is highly prone to marker misplacement-induced error. The purpose of this study was to develop an efficient algorithm for post-hoc correction of the knee flexion axis and test its efficacy relative to other established algorithms. Gait data were collected on twelve healthy subjects using standard marker placement as well as intentionally misplaced lateral knee markers. The efficacy of the algorithm was assessed by quantifying the reduction in knee angle errors. Crosstalk error was quantified from the coefficient of determination (r(2)) between knee flexion and adduction angles. Mean rotation offset error (αo) was quantified from the knee and hip rotation kinematics across the gait cycle. The principal component analysis (PCA)-based algorithm significantly reduced r(2) (p<0.001) and caused αo,knee to converge toward 11.9±8.0° of external rotation, demonstrating improved certainty of the knee kinematics. The within-subject standard deviation of αo,hip between marker placements was reduced from 13.5±1.5° to 0.7±0.2° (p<0.001), demonstrating improved precision of the knee kinematics. The PCA-based algorithm performed at levels comparable to a knee abduction-adduction minimization algorithm (Baker et al., 1999) and better than a null space algorithm (Schwartz and Rozumalski, 2005) for this healthy subject population.

Compressive and shear hip joint contact forces are affected by pediatric obesity during walking

Obese children exhibit altered gait mechanics compared to healthy-weight children and have an increased prevalence of hip pain and pathology. This study sought to determine the relationships between body mass and compressive and shear hip joint contact forces during walking. Kinematic and kinetic data were collected during treadmill walking at 1ms(-1) in 10 obese and 10 healthy-weight 8-12 year-olds. We estimated body composition, segment masses, lower-extremity alignment, and femoral neck angle via radiographic images, created personalized musculoskeletal models in OpenSim, and computed muscle forces and hip joint contact forces. Hip extension at mid-stance was 9° less, on average, in the obese children (p<0.001). Hip abduction, knee flexion, and body-weight normalized peak hip moments were similar between groups. Normalized to body-weight, peak contact forces were similar at the first peak and slightly lower at the second peak between the obese and healthy-weight participants. Total body mass explained a greater proportion of contact force variance compared to lean body mass in the compressive (r(2)=0.89) and vertical shear (perpendicular to the physis acting superior-to-inferior) (r(2)=0.84) directions; lean body mass explained a greater proportion in the posterior shear direction (r(2)=0.54). Stance-average contact forces in the compressive and vertical shear directions increased by 41N and 48N, respectively, for every kilogram of body mass. Age explained less than 27% of the hip loading variance. No effect of sex was found. The proportionality between hip loads and body-weight may be implicated in an obese child׳s increased risk of hip pain and pathology.

The impact of body fat on three dimensional motion of the paediatric foot during walking

Childhood obesity is commonly associated with a pes planus foot type and altered lower limb joint function during walking. However, limited information has been reported on dynamic intersegment foot motion with the level of obesity in children. The aim of this study was to explore the relationships between intersegment foot motion during gait and body fat in boys age 7-11 years. Fat mass was measured in fifty-five boys using air displacement plethysmography. Three-dimensional gait analysis was conducted on the right foot of each participant using the 3DFoot model to capture angular motion of the shank, calcaneus, midfoot and metatarsals. Two multivariate statistical techniques were employed; principle component analysis reduced the multidimensional nature of gait analysis, and multiple linear regression analysis accounted for potential confounding factors. Higher fat mass predicted greater plantarflexion of the calcaneus during the first half and end of stance phase and at the end of swing phase. Greater abduction of the calcaneus throughout stance and swing was predicted by greater fat mass. At the midfoot, higher fat mass predicted greater dorsiflexion and eversion throughout the gait cycle. The findings present novel information on the relationships between intersegment angular motion of the foot and body fat in young boys. The data indicates a more pronated foot type in boys with greater body fat. These findings have clinical implications for pes planus and a predisposition for pain and discomfort during weight bearing activities potentially reducing motivation in obese children to be physically active.

Pediatric obesity and walking duration increase medial tibiofemoral compartment contact forces

With the high prevalence of pediatric obesity there is a need for structured physical activity during childhood. However, altered tibiofemoral loading during physical activity in obese children likely contribute to their increased risk of orthopedic disorders of the knee. The goal of this study was to determine the effects of pediatric obesity and walking duration on medial and lateral tibiofemoral contact forces. We collected experimental biomechanics data during treadmill walking at 1 m•s(-1) for 20 min in 10 obese and 10 healthy-weight 8-12 year-olds. We created subject-specific musculoskeletal models using radiographic measures of tibiofemoral alignment and centers-of-pressure, and predicted medial and lateral tibiofemoral contact forces at the beginning and end of each trial. Obesity and walking duration affected tibiofemoral loading. At the beginning of the trail, the average percent of the total load passing through the medial compartment during stance was 85% in the obese children and 63% in the healthy-weight children; at the end of the trial, the medial distribution was 90% in the obese children and 72% in the healthy-weight children. Medial compartment loading rates were 1.78 times greater in the obese participants. The medial compartment loading rate increased 17% in both groups at the end compared to the beginning of the trial (p = 0.001). We found a strong linear relationship between body-fat percentage and the medial-lateral load distribution (r(2) = 0.79). Altered tibiofemoral loading during walking in obese children may contribute to their increased risk of knee pain and pathology.

The effects of a strength and neuromuscular exercise programme for the lower extremity on knee load, pain and function in obese children and adolescents: study protocol for a randomised controlled trial

BACKGROUND

Childhood obesity is one of the most critical and accelerating health challenges throughout the world. It is a major risk factor for developing varus/valgus misalignments of the knee joint. The combination of misalignment at the knee and excess body mass may result in increased joint stresses and damage to articular cartilage. A training programme, which aims at developing a more neutral alignment of the trunk and lower limbs during movement tasks may be able to reduce knee loading during locomotion. Despite the large number of guidelines for muscle strength training and neuromuscular exercises that exist, most are not specifically designed to target the obese children and adolescent demographic. Therefore, the aim of this study is to evaluate a training programme which combines strength and neuromuscular exercises specifically designed to the needs and limitations of obese children and adolescents and analyse the effects of the training programme from a biomechanical and clinical point of view.

METHODS/DESIGN

A single assessor-blinded, pre-test and post-test randomised controlled trial, with one control and one intervention group will be conducted with 48 boys and girls aged between 10 and 18 years. Intervention group participants will receive a 12-week neuromuscular and quadriceps/hip strength training programme. Three-dimensional (3D) gait analyses during level walking and stair climbing will be performed at baseline and follow-up sessions. The primary outcome parameters for this study will be the overall peak external frontal knee moment and impulse during walking. Secondary outcomes include the subscales of the Knee injury and Osteoarthritis Outcome Score (KOOS), frontal and sagittal kinematics and kinetics for the lower extremities during walking and stair climbing, ratings of change in knee-related well-being, pain and function and adherence to the training programme. In addition, the training programme will be evaulated from a clinical and health status perspective by including the following analyses: cardiopulmonary testing to quantify aerobic fitness effects, anthropometric measures, nutritional status and psychological status to characterise the study sample.

DISCUSSION

The findings will help to determine whether a neuromuscular and strength training exercise programme for the obese children population can reduce joint loading during locomotion, and thereby decrease the possible risk of developing degenerative joint diseases later in adulthood.

TRIAL REGISTRATION

ClinicalTrials NCT02545764 , Date of registration: 24 September 2015.

Collection of normative data for spatial and temporal gait parameters in a sample of French children aged between 6 and 12

OBJECTIVE

Normative data on gait is essential for clinical practice - especially in children whose gait pattern changes over time. Sets of normative gait data in healthy children vary significantly from one country to another. We decided to generate a specific reference database of gait parameters for French children.

METHOD

Three hundred and eighty-two children (228 boys and 154 girls, aged between 6 and 12) were asked to walk as naturally as possible and at a self-selected speed on a GAITRite track. Velocity, step count, cadence, step time, step length, cycle time, stride length, base width, swing time, stance time, single support time and double support time were recorded. Parameters were analyzed by age group, height group and BMI.

RESULTS

Velocity, step and stride length increased regularly with advancing age and height. Cadence decreased with height. All temporal parameters (except for double support) differed significantly (P<0.05) when comparing the 6-year-old group or the 7-year-old group with the 9-year-old group and older groups. A small number of temporal parameters (cadence, step time, cycle time and stance time) differed significantly when comparing 7-year-olds and 8-year-olds. Temporal parameters appeared rise in proportion height from 110 cm to 130 cm and then reached a plateau. Overweight was associated with a longer stance time and more double support.

CONCLUSION

The gait pattern in French children aged between 6 and 12 differs from those recorded elsewhere in the world; although gait parameters appear to change in much the same way with age worldwide, our values (even when normalized) are different. Our local database should be of value in French studies of childhood gait disorders. Given that gait patterns do not appear to mature by the age of 12, it would be valuable to study gait patterns in a population of teenagers.

Musculoskeletal Function and Obesity: Implications for Physical Activity

However quantified, obesity is a global health problem of significant magnitude. The condition is no longer limited to the developed world, with an increasing proportion of low-to-middle income countries burdened by obesity and its comorbidities. Specifically, obesity is a risk factor for a raft of psychosocial, physiological, cardiovascular, and metabolic problems. The carriage of excess body weight, including an unhealthy proportion of body fat, also has important implications for musculoskeletal health. To date, this important relationship has not received as much attention by the research community. Coincidentally, there has been a heightened interest in the role of physical activity and exercise across the lifespan in the prevention, treatment and management of obesity. This paper considers some of the more common musculoskeletal problems in children, adolescents and adults with implications for the overweight and obese and their meaningful engagement in physical activity.

The energy cost of playing active video games in children with obesity and children of a healthy weight

BACKGROUND

Increasing physical activity and reducing sedentary behaviour form a large part of the treatment of paediatric obesity. However, many children today spend prolonged periods of time playing sedentary video games. Active video games (AVGs) represent a novel and child friendly form of physical activity.

OBJECTIVES

To measure the energy cost of playing two AVGs in children with obesity and healthy age- and gender-matched children.

METHODS

The energy cost of gaming and heart rates achieved during gaming conditions were compared between groups.

RESULTS

AVG play can result in light-to-moderate intensity physical activity (2.7-5.4 metabolic equivalents). When corrected for fat-free mass those with obesity expended significantly less energy than healthy weight peers playing Nintendo Wii Fit Free Jogging (P = 0.017). No significant difference was seen between groups in the energy cost of playing Boxing.

CONCLUSION

Certain AVGs, particularly those that require lower limb movement, could be used to increase total energy expenditure, replace more sedentary activities, or achieve moderate intensity physical activity among children with obesity. There seems to be some differences in how children with obesity and children of a healthy weight play AVGs. This could result in those with obesity expending less energy than their lean peers during AVG play.

The effects of pediatric obesity on dynamic joint malalignment during gait

BACKGROUND

There is a greater prevalence of lower extremity malalignment in obese children during static posture; however, there has been less examination of dynamic joint function in this cohort. Therefore, the purpose of this study was to determine kinematic differences that exist between obese and non-obese children that would support previously reported static joint malalignment.

METHODS

Forty children were classified as obese (n=20) or non-obese (n=20). Lower extremity joint kinematics were collected during five walking trials at a self-selected pace. Peak joint displacement and amount of joint motion throughout the gait cycle (calculated as the integrated displacement curve) were analyzed for group differences.

FINDINGS

Non-obese children had greater peak knee and hip extension during gait; however, there were no group differences in the integrated sagittal displacement curve. Obese children had greater peak angular displacement and integrals of angular displacement for peak hip adduction, hip internal rotation, and foot abduction (toe-out) than non-obese children. Obese children also had greater peak knee external rotation than non-obese children.

INTERPRETATION

Non-obese children showed greater range of motion in the sagittal plane, particularly at the hip and knee. Frontal and transverse plane differences suggest that obese children function in a more genu valgum position than non-obese children. Static measures of genu valgum have been previously associated with pediatric obesity; the findings indicate that there are also dynamic implications of said malalignment in obese children. Genu valgum presents increased risk of osteoarthritis for obese children and should be considered when prescribing weight bearing exercise to this cohort.

Effect of shoe flexibility on plantar loading in children learning to walk

BACKGROUND

In a previous pilot study of "cruisers" (nonindependent ambulation), "early walkers" (independent ambulation for 0-5 months), and "experienced walkers" (independent ambulation for 6-12 months), developmental age significantly affected the children's stability when walking and performing functional activities. We sought to examine how shoe structural characteristics affect plantar pressure distribution in early walkers.

METHODS

Torsional flexibility was evaluated in four shoe designs (UltraFlex, MedFlex, LowFlex, and Stiff based on decreasing relative flexibility) with a structural testing machine. Plantar pressures were recorded in 25 early walkers while barefoot and shod at self-selected walking speeds. Peak pressure was calculated over ten masked regions for the barefoot and shod conditions.

RESULTS

Torsional flexibility, the angular rotation divided by the applied moment about the long axis of the shoe, was different across the four shoe designs. As expected, UltraFlex was the most flexible and Stiff was the least flexible. As applied moment increased, torsional flexibility decreased in all footwear. When evaluating early walkers during gait, peak pressure was significantly different across shoe conditions for all of the masked regions. The stiffest shoe had the lowest peak pressures and the most flexible shoe had the highest.

CONCLUSIONS

It is likely that increased shoe flexibility promoted greater plantar loading. Plantar pressures while wearing the most flexible shoe are similar to those while barefoot. This mechanical feedback may enhance proprioception, which is a desirable attribute for children learning to walk.

Metabolic cost, mechanical work, and efficiency during normal walking in obese and normal-weight children

PURPOSE

This study aimed to investigate the influence of childhood obesity on energetic cost during normal walking and to determine if obese children choose a walking strategy optimizing their gait pattern.

METHOD

Sixteen obese children with no functional abnormalities were matched by age and gender with 16 normal-weight children. All participants were asked to walk along a nearly circular track 30 m in length at a self-selected speed. Spatiotemporal data, kinematics, and ground reaction force were collected during walking using a three-dimensional motion analysis system. Metabolic cost was collected by a portable gas analyzer simultaneously.

RESULTS

The mechanical energy expenditure (MEE) was 72.7% higher in obese children than in normal-weight children. The net metabolic cost was 65.7% higher in obese children. No difference was found in the metabolic rate (J x kg(-1) x m(-1)), normalized MEE (J x kg(-1) x m(-1)) and mechanical efficiency between the obese and normal-weight groups. The obese children walked with a 0.15 m/s slower walking speed, 10.0% shorter cadence, and 30.9% longer double-support phase compared with normal-weight children. In addition, no differences were found in the mediolateral and vertical body center of mass displacement.

CONCLUSION

Body mass played a dominant role in the total metabolic and mechanical cost per stride. Obese children may adopt a walking strategy to avoid an increase in the metabolic cost and the mechanical work required to move their excess body mass.

The application of computer musculoskeletal modeling and simulation to investigate compressive tibiofemoral force and muscle functions in obese children

This study aimed to utilize musculoskeletal modelling and simulation to investigate the compressive tibiofemoral force and individual muscle function in obese children. We generated a 3D muscle-driven simulation of eight obese and eight normal-weight boys walking at their self-selected speed. The compressive tibiofemoral force and individual muscle contribution to the support and progression accelerations of center of mass (COM) were computed for each participant based on the subject-specific model. The simulated results were verified by comparing them to the experimental kinematics and EMG data. We found a linear relationship between the average self-selected speed and the normalized peak compressive tibiofemoral force (R² = 0.611). The activity of the quadriceps contributed the most to the peak compressive tibiofemoral force during the stance phase. Obese children and nonobese children use similar muscles to support and accelerate the body COM, but nonobese children had significantly greater contributions of individual muscles. The obese children may therefore adopt a compensation strategy to avoid increasing joint loads and muscle requirements during walking. The absolute compressive tibiofemoral force and muscle forces were still greater in obese children. The long-term biomechanical adaptations of the musculoskeletal system to accommodate the excess body weight during walking are a concern.

Musculoskeletal pain in overweight and obese children

This review seeks to provide a current overview of musculoskeletal pain in overweight and obese children. Databases searched were Academic Search Complete, CINAHL, Medline, Proquest Health and Medical Complete, Scopus, Google Scholar, SPORTDiscuss and Trove for studies published between 1 January 2000 and 30 December 2012. We used a broad definition of children within a 3- to 18-year age range. The search strategy included the following terms: obesity, morbid obesity, overweight, pain, musculoskeletal pain, child, adolescent, chronic pain, back pain, lower back pain, knee pain, hip pain, foot pain and pelvic pain. Two authors independently assessed each record, and any disagreement was resolved by the third author. Data were analysed using a narrative thematic approach owing to the heterogeneity of reported outcome measures. Ninety-seven records were initially identified using a variety of terms associated with children, obesity and musculoskeletal pain. Ten studies were included for thematic analysis when predetermined inclusion criteria were applied. Bone deformity and dysfunction, pain reporting and the impact of children being overweight or obese on physical activity, exercise and quality of life were the three themes identified from the literature. Chronic pain, obesity and a reduction in physical functioning and activity may contribute to a cycle of weight gain that affects a child's quality of life. Future studies are required to examine the sequela of overweight and obese children experiencing chronic musculoskeletal pain.

Mass affects lower extremity muscle activity patterns in children's gait

Overweight children demonstrate biomechanical differences during gait; however it is not known if these differences occur within active or passive tissue. The purpose of this study was to examine differences in lower extremity muscle activation patterns of children with different body mass during three walking speeds. Twenty children (8-12 years) were recruited and classified as overweight (OW), normal-weight (NW), or underweight (UW). Electromyography was recorded for vastus lateralis, semitendinosus, gastrocnemius, and tibialis anterior while participants walked on a treadmill at slow (SP), self-selected (SSP), and fast (FP) speeds. Differences in group and walking speed were analyzed for duration of muscle activation (presented as a percentage of stride, stance, or swing phases). Compared to OW, UW experienced greater duration of vastus lateralis and tibialis anterior activation during the swing phase. OW had greater duration of gastrocnemius activation during stride than UW. Increased walking speed resulted in greater duration of vastus lateralis activation for all groups. NW also exhibited greater duration of tibialis anterior activation at faster walking speeds. During FP, OW had greater duration of gastrocnemius activity during stance, but lower duration during swing. These findings are consistent with the idea that children with greater mass adopt a more passive gait strategy during swing to maximize energy recovery. Increased duration of gastrocnemius activity during stance also provides greater stability and stronger propulsion, which corroborates previous research. These findings help to understand the neuromuscular mechanisms associated with previous biomechanical findings in children's gait.

Foot loading patterns in normal weight, overweight and obese children aged 7 to 11 years

Background

Childhood obesity is thought to predispose to structural foot changes and altered foot function. Little is currently understood about whether similar changes occur in overweight children. The aim of this study was determine foot loading characteristics in obese, overweight and normal weight children aged 7 to 11 years during level walking.

Methods

Dynamic plantar pressures were measured in 22 obese, 22 overweight and 56 normal weight children recruited from local primary and secondary schools in East London. Peak pressure, peak force, normalised peak force, pressure–time and force-time integrals were analysed at six regions of the plantar foot: lateral heel, medial heel, midfoot, 1st metatarsophalangeal joint, 2nd-5th metatarsophalangeal joint and hallux. A one-way ANOVA was used to test for significant differences in variables across the groups. Where differences existed Tukey post-hoc tests were used to ascertain the location of the difference.

Results

Children who were obese and overweight demonstrated significantly (p<0.05) higher peak pressures and peak forces as well as significantly higher force-time and pressure–time integrals under the midfoot and 2nd-5th metatarsal regions. After normalisation of peak force, similar trends existed where the obese and overweight children demonstrated significantly (p<0.05) greater loading at the midfoot and 2nd-5th metatarsals.

Conclusion

Findings from this study indicated that overweight children, as young as seven, displayed differences in foot loading during walking, when compared with normal weight children. These findings were consistent with loading patterns of children who were obese and suggest that early assessment and intervention may be required in overweight children to mitigate against the development of musculoskeletal complications associated with excessive body mass.

The association between functional movement and overweight and obesity in British primary school children

Background

The purpose of this study was to examine the association between functional movement and overweight and obesity in British children.

Methods

Data were obtained from 90, 7–10 year old children (38 boys and 52 girls). Body mass (kg) and height (m) were assessed from which body mass index (BMI) was determined and children were classified as normal weight, overweight or obese according to international cut offs. Functional movement was assessed using the functional movement screen.

Results

Total functional movement score was significantly, negatively correlated with BMI (P = .0001). Functional movement scores were also significantly higher for normal weight children compared to obese children (P = .0001). Normal weight children performed significantly better on all individual tests within the functional movement screen compared to their obese peers (P <0.05) and significantly better than overweight children for the deep squat (P = .0001) and shoulder mobility tests (P = .04). Overweight children scored significantly better than obese in the hurdle step (P = .0001), in line lunge (P = .05), shoulder mobility (P = .04) and active straight leg raise (P = .016).

Functional movement scores were not significantly different between boys and girls (P > .05) when considered as total scores. However, girls performed significantly better than boys on the hurdle step (P = .03) and straight leg raise (P = .004) but poorer than boys on the trunk stability push-up (P = .014).

Conclusions

This study highlights that overweight and obesity are significantly associated with poorer functional movement in children and that girls outperform boys in functional movements.

Consequences of pediatric obesity on the foot and ankle complex

BACKGROUND

Anthropometric status can influence gait biomechanics, but there is relatively little published research regarding foot and ankle characteristics in the obese pediatric population. We sought to compare the structural and functional characteristics of the foot and ankle complex in obese and non-obese children.

METHODS

Twenty healthy children (ten obese and ten normal weight) were recruited for a cross-sectional research study. Anthropometric parameters were measured to evaluate active ankle dorsiflexion, arch height (arch height index, arch rigidity index ratio, and arch drop), foot alignment (resting calcaneal stance position and forefoot-rearfoot alignment in unloaded and loaded positions), and foot type (malleolar valgus index). Independent t tests determined significant differences between groups for all assessed parameters. Statistical significance was set at P < .0125.

RESULTS

Compared with non-obese participants, obese participants had significantly greater arch drop (mean ± SD: 5.10 ± 2.13 mm versus 2.90 ± 1.20 mm; P =.011) and a trend toward lower arch rigidity index ratios (mean ± SD: 0.92 ± 0.03 versus 0.95 ± 0.02; P = .013). In addition, obese participants had significantly less active ankle dorsiflexion at 90° of knee flexion versus non-obese participants (mean ± SD: 19.57 ± 5.17 versus 29.07 ± 3.06; P < .001). No significant differences existed between groups for any other anthropometric measurements.

CONCLUSIONS

The decreased active ankle dorsiflexion in the obese group can increase foot contact for a longer period of the stance phase of gait. Obese participants also presented with a more flexible foot when bearing weight.

Comparison of measures of physical performance among young children who are healthy weight, overweight, or obese

PURPOSE

To determine the differences in gait, balance, muscle strength, and physical activity in young children who are healthy weight (HW), overweight (OW), or obese.

METHODS

Participants (n = 70; 5-9 years) were classified according to their body mass index as OW/obese (n = 29) or HW (n = 41). Data were collected on gait parameters, 1-leg stance test (OLST), handgrip strength, vertical jump (VJ) height, and physical activity. An independent t test, Mann-Whitney U test, analysis of covariance (ANCOVA), and regression analyses were carried out.

RESULTS

Being OW/obese resulted in a significantly increased base of support while walking (P < .05), decreased OLST performance (P < .05), and decreased VJ height (P < .01) compared with peers of HW.

CONCLUSION

These findings suggest that in young children, being OW/obese may lead to an increased base of support while walking, decreased balance, and decreased leg explosive strength.