Association between body mass index and functional fitness of 9- to 10-year-old Chilean children

The relative contributions of adiposity and activity levels to physical performance in children with excess weight

OBJECTIVE

This study examined predictors of physical performance, a key aspect of quality of life, in children with excess weight.

METHODS

Participants were 269 children aged 6-12 years with a body mass index above the 85th percentile. Children completed a standardized physical performance task capturing lower extremity strength, balance, and gait speed. Height, weight, and waist circumference were objectively measured, and daily moderate-vigorous physical activity (min/day) and sedentary time (% of day) were assessed with a 7-day accelerometer protocol.

RESULTS

Physical performance task completion averaged 15.0 (SD = 2.5) seconds. Children with higher body mass index z-scores and waist circumferences had significantly longer task completion times. The task took 1.8 additional seconds per 1.0 body mass index z-score (p < .001), and 1.2 additional seconds for every 20 cm higher waist circumference (p < .001). Daily moderate-vigorous physical activity and sedentary time were unrelated to physical performance, and did not moderate its associations with the adiposity measures.

CONCLUSION

Among children with excess weight, physical performance declines with increasing levels of total and central adiposity. Daily activity levels do not moderate this association. Interventions that directly target weight reduction would likely yield the greatest improvement in physical performance in children with overweight or obesity.

Obesity Indices for Predicting Functional Fitness in Children and Adolescents With Obesity

Objectives: We aimed to determine the obesity indices that affect 6-min walk test (6-MWT) distance in children and adolescents with obesity and to compare the 6-MWT distance of obese subjects with that of normal-weight subjects. Methods: Obese children and adolescents aged 8-15 years and normal-weight age- and gender-matched controls were enrolled. All participants performed the 6-MWT; respiratory muscle strength (RMS), including maximal inspiratory pressure and maximal expiratory pressure; and spirometry. Data between groups were compared. In the obesity group, correlation between obesity indices and pulmonary function testing (6-MWT, RMS, and spirometry) was analyzed. Results: The study included 37 obese and 31 normal-weight participants. The following parameters were all significantly lower in the obesity group than in the normal-weight group: 6-MWT distance (472.1 ± 66.2 vs. 513.7 ± 72.9 m; p = 0.02), forced expiratory volume in one second/forced vital capacity (FEV1/FVC) (85.3 ± 6.7 vs. 90.8 ± 4.5%; p < 0.001), forced expiratory flow rate within 25-75% of vital capacity (FEF25-75%) (89.8 ± 23.1 vs. 100.4 ± 17.3 %predicted; p = 0.04), and peak expiratory flow (PEF) (81.2 ± 15 vs. 92.5 ± 19.6 %predicted; p = 0.01). The obesity indices that significantly correlated with 6-MWT distance in obese children and adolescents were waist circumference-to-height ratio (WC/Ht) (r = -0.51; p = 0.001), waist circumference (r = -0.39; p = 0.002), body mass index (BMI) (r = -0.36; p = 0.03), and chest circumference (r = -0.35; p = 0.04). WC/Ht was the only independent predictor of 6-MWT distance by multiple linear regression. Conclusions: Children and adolescents with obesity had a significantly shorter 6-MWT distance compared with normal-weight subjects. WC/Ht was the only independent predictor of 6-MWT distance in the obesity group.

Health-Related Motor Testing of Children in Primary School: A Systematic Review of Criterion-Referenced Standards

Being physically fit in younger years prevents several diseases in the presence as well as in the life course. Therefore, monitoring physical fitness and motor competence through motor testing is essential for determining developmental status and identifying health-related risks. The main objectives of this systematic review were (1) to identify currently available health-related criterion-referenced standards and cut-off points for physical fitness and motor competence test items, (2) to frame the methodological background on setting health-related criterion-referenced standards and (3) to give implications for a health-related evaluation system for physical fitness and motor competence tests. The electronic data base search (PubMed, Web of Science and SURF) yielded 2062 records in total and identified six empirical studies reporting cut-off points of motor test items for children (7-10 years), as well as 30 methodological papers discussing determination approaches to health-related criterion-referenced standards. Data collection, selection and analyses followed the PRISMA guidelines. Health-related motor test standards need to be gender- and age-specific but should refer to an absolute cut-off point rather than to relative performance in the reference group. Due to the lack of data on health-related criterion referenced standards, receiver-operating-characteristic (ROC) curves provide a tool for the determination of cut-off points and criterion referenced standards for physical fitness and motor competence tests. A standardized approach forms the fundamental base for a globally applicable evaluation of health-related fitness tests.

Physiological Responses at Rest and Exercise to High Altitude in Lowland Children and Adolescents

During the last decades, the number of lowland children exposed to high altitude (HA) has increased drastically. Several factors may influence the development of illness after acute HA exposure on children and adolescent populations, such as altitude reached, ascent velocity, time spent at altitude and, especially, their age. The main goal of this study was to evaluate the resting cardiorespiratory physiological and submaximal exercise responses under natural HA conditions by means of the six-minute walking test (six MWT). Secondly, we aimed to identify the signs and symptoms associated with acute mountain sickness (AMS) onset after acute HA exposure in children and adolescents. Forty-two children and adolescents, 18 boys and 24 girls aged from 11 to 15 years old, participated in this study, which was performed at sea level (SL) and during the first 42 h at HA (3330 m). The Lake Louise score (LLS) was recorded in order to evaluate the evolution of AMS symptoms. Submaximal exercise tests (six MWT) were performed at SL and HA. Physiological parameters such as heart rate, systolic and diastolic blood pressure, respiratory rate and arterialized oxygen saturation were measured at rest and after ending exercise testing at the two altitudes. After acute HA exposure, the participants showed lower arterial oxygen saturation levels at rest and after the submaximal test compared to SL (p < 0.001). Resting heart rate, respiratory rate and diastolic blood pressure presented higher values at HA (p < 0.01). Moreover, heart rate, diastolic blood pressure and dyspnea values increased before, during and after exercise at HA (p < 0.01). Moreover, submaximal exercise performance decreased at HA (p < 0.001). The AMS incidence at HA ranged from 9.5% to 19%, with mild to moderate symptoms. In conclusion, acute HA exposure in children and adolescent individuals produces an increase in basal cardiorespiratory parameters and a decrement in arterial oxygen saturation. Moreover, cardiorespiratory parameters increase during submaximal exercise at HA. Mild to moderate symptoms of AMS at 3330 m and adequate cardiovascular responses to submaximal exercise do not contraindicate the ascension of children and adolescents to that altitude, at least for a limited period of time.