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.

Can research align with service? Lessons learned from the Big Experiment and National Biomechanics Day.

Public engagement is an important role for the university academic, but is often neglected due to perceived lack of time and prioritized commitments in research and teaching. Yet, public engagement events offer an untapped opportunity for researchers to collect data from members of the general public who arrive on site at university labs. These engagement events could allow for data collection as part of didactic and demonstrative outreach events to be used in research and science. In this proof of concept study, a collaborative group of international researchers investigated the feasibility of embedding research quality assessment into events surrounding National Biomechanics Day. The Big Experiment collected data on 501 secondary school students (age range: 13 to 18 years) across 9 university sites within a 24-hour period. Data included maximal vertical jump height and self-reported physical activity levels. Vertical jump height was positively correlated to participant height, but not age or body mass. Very physically active students had significantly higher vertical jump heights than individuals who reported being somewhat or not physically active. This feasibility project demonstrates that with substantial preparation and a simple research design, focused research questions can be incorporated into educational outreach initiatives and ultimately provide a rich data source.

Metabolic Differences Between Shod and Barefoot Walking in Children.

Footwear affects the biomechanics of children's gait; however, there has been less research addressing the energetics of walking with and without shoes. This study investigated the effects of barefoot and shod walking on metabolic parameters in children. 25 children (9.7±1.4 years) walked at a self-selected pace for 5 min on an instrumented treadmill under 2 footwear conditions (barefoot, running shoe). Vertical oscillations of centre of mass were calculated from ground reaction forces. Expired gases were collected in the last minute of each trial. Paired t-tests revealed significantly higher oxygen consumption (17.6±2.5 ml.kg(-1).min(-1) vs. 16.3±3.1 ml.kg(-1).min(-1)), energy expenditure (3.25±0.86 kcal.min(-1) vs. 2.97±0.68 kcal.min(-1)), and economy (298.2±47.5 ml.kg(-1).km(-1) vs. 275.9±56.9 ml.kg(-1).km(-1)) during the shod condition. There was no difference in substrate utilization between conditions. The barefoot condition elicited a smaller centre of mass vertical displacement (1.24±0.14 cm vs. 1.34±0.17 cm). At a natural walking speed, barefoot walking is more economical than shod walking at the same velocity in children. The higher energy cost of shod walking should be considered when evaluating the use of footwear by children.

Knee alignment can help predict sedentary behaviour in children: a pilot study.

AIM: The purpose of this pilot study was to introduce knee alignment as a potential predictor of sedentary activity levels in boys and girls. METHODS: Dual energy x-ray absorptiometry (DXA) and anthropometric assessment were conducted on 47 children (21 boys and 26 girls; 5-14 y) and their gender-matched parent. Body Mass Index (BMI) and abdominal-to-height ratio were calculated. Lower extremity alignment was determined by anatomic tibiofemoral angle (TFA) measurements from DXA images. Time spent in moderate-to-vigorous physical activity and sedentary activities were obtained from a parent-reported questionnaire. Stepwise multiple regression analyses identified anthropometric, musculoskeletal, and activity factors of parents and children for predicting total time spent in sedentary behaviour. RESULTS: Weight, total sedentary time of parents and TFA are moderate predictors of sedentary behaviour in children (R2=0.469). When stratifying for gender, TFA and total sedentary time of the parent, as well as waist circumference, are the most useful predictors of sedentary behaviour in boys (R2=0.648). However, weight is the only predictor of sedentary behaviour in girls (R2=0.479). CONCLUSION: Negative associations between TFA and sedentary behaviour indicate that even slight variations in musculoskeletal alignment may influence a child's motivation to be physically active. Although growth and development is complicated by many potentialities, this pilot study suggests that orthopaedic factors should also be considered when evaluating physical activity in children.

Resistance training for obese, type 2 diabetic adults: a review of the evidence.

In both developed and developing countries, increased prevalence of obesity has been strongly associated with increased incidence of type 2 diabetes mellitus (T2DM) in the adult population. Previous research has emphasized the importance of physical activity in the prevention and management of obesity and T2DM, and generic exercise guidelines originally developed for the wider population have been adapted for these specific populations. However, the guidelines traditionally focus on aerobic training without due consideration to other exercise modalities. Recent reviews on resistance training in the T2DM population have not compared this modality with others including aerobic training, or considered the implications of resistance training for individuals suffering from both obesity and T2DM. In short, the optimal mix of exercise modalities in the prescription of exercise has not been identified for it benefits to the metabolic, body composition and muscular health markers common in obesity and T2DM. Similarly, the underlying physical, social and psychological barriers to adopting and maintaining exercise, with the potential to undermine the efficacy of exercise interventions, have not been addressed in earlier reviews. Because it is well established that aerobic exercise has profound effects on obesity and T2DM risk, the purpose of this review was to address the importance of resistance training to obese adults with T2DM.

Paediatric obesity, physical activity and the musculoskeletal system.

The current epidemic of paediatric obesity is consistent with a myriad of health-related comorbid conditions. Despite the higher prevalence of orthopaedic conditions in overweight children, a paucity of published research has considered the influence of these conditions on the ability to undertake physical activity. As physical activity participation is directly related to improvements in physical fitness, skeletal health and metabolic conditions, higher levels of physical activity are encouraged, and exercise is commonly prescribed in the treatment and management of childhood obesity. However, research has not correlated orthopaedic conditions, including the increased joint pain and discomfort that is commonly reported by overweight children, with decreases in physical activity. Research has confirmed that overweight children typically display a slower, more tentative walking pattern with increased forces to the hip, knee and ankle during 'normal' gait. This research, combined with anthropometric data indicating a higher prevalence of musculoskeletal malalignment in overweight children, suggests that such individuals are poorly equipped to undertake certain forms of physical activity. Concomitant increases in obesity and decreases in physical activity level strongly support the need to better understand the musculoskeletal factors associated with the performance of motor tasks by overweight and obese children.