[Should physical activity be contraindicated during pregnancy in relation to its potentially related risks?] / L'activité physique devrait-elle être contre-indiquée pendant la grossesse au regard des risques qui lui sont potentiellement associés ?

OBJECTIVE: This paper aimed at providing a critical analysis of data on the risks associated with physical activity of women during their pregnancy. METHODS: Cochrane Library, Google Scholar, PubMed (Medline) and Web of Sciences were searched using a combination of MeSH terms associated to "Physical activity", "Pregnancy" and "Adverse events" or "Risks". Only review papers published from inception of these databases to November 2016 were used in the present analysis. RESULTS: The electronic search yield a total of 104 citations. After a critical analysis of abstracts and/or full-texts, only a systematic review and cohort study on injuries related to physical activity during pregnancy appeared relevant for the current study. Data reveals a very small proportion (<1 %) of adverse events in direct link with the physical activity behavior of pregnant women. Furthermore, there would be less than one serious adverse event per 5000hours of physical activity. The only serious adverse event attributable to physical activity during pregnancy was uterine contractions. The threat of preterm labor and miscarriage risk cannot be primarily attributed to the participation of pregnant women in a physical activity, even vigorous. Moreover, no adverse effects of maternal physical activity on neonatal outcomes were found. CONCLUSION: Physical activity-related risks during pregnancy appear to be infrequent and of minor severity. Though further studies are required to better understand the risk/benefit balance of physical activity during pregnancy, current data do not support the contraindication of this behavior in pregnant women.

Body mass index and childhood obesity classification systems: A comparison of the French, International Obesity Task Force (IOTF) and World Health Organization (WHO) references.

AIM: This study aims to compare three body mass index (BMI)-based classification systems of childhood obesity: the French, the International Obesity Task Force (IOTF) and the World Health Organization (WHO) references. METHODS: The study involved 1382 schoolchildren, recruited from the Lille Academic District in France in May 2009 aged 8.4±1.7 years (4.0-12.0 years). Their mean height and body mass were 131.5±10.9cm and 30.7±9.2kg, respectively, resulting in a BMI of 17.4±3.2kg/m(2). The weight status was defined according to the three systems considered in this study. The agreement between these references was tested using the Cohen's kappa coefficient. RESULTS: The prevalence of overweight was higher with the WHO references (20.0%) in comparison with the French references (13.8%; P<0.0001) and the IOTF (16.2%; P≤0.01). A similar result was found with obesity (WHO: 11.6% vs. IOTF: 6.7%; or French references: 6.7%; P<0.0001). Agreement between the three references ranged from "moderate" to "perfect" (0.43≤κ≤1.00; P<0.0001). Kappa coefficients were higher when the three references were used to classify children as obese (0.63≤κ≤1.00; P<0.0001) as compared to classification in the overweight (obesity excluded) category (0.43≤κ≤0.94; P<0.0001). When sex and age categories (4-6 years vs. 7-12 years) were considered to define the overweight status, the lowest kappa coefficient was found between the French and WHO references in boys aged 7-12 years (κ=0.28; P<0.0001), and the highest one in girls aged 7-12 years between the French references and IOTF (κ=0.97; P<0.0001). As for obesity, agreement between the three references ranged from 0.60 to 1.00 (P<0.0001), with the lowest values obtained in the comparison of the WHO references against French references or IOTF among boys aged 7-12 years (κ=0.60; P<0.0001). CONCLUSION: Overall, the WHO references yield an overestimation in overweight and/or obesity within this sample of schoolchildren as compared to the French references and the IOTF. The magnitude of agreement coefficients between the three references depends on of both sex and age categories. The French references seem to be in rather close agreement with the IOTF in defining overweight, especially in 7-12-year-old children.

Does the body adiposity index (BAI) apply to paediatric populations?

OBJECTIVE: Validation of body adiposity index (BAI) in a paediatrics sample; and to develop, if necessary, a valid BAI for paediatrics (i.e. BAIp). METHODS: A total of 1615 children (52% boys) aged 5-12 years underwent anthropometry. Their body composition was assessed using a foot-to-foot bioimpedance. The validity of BAI = (Hip circumference/Height(1.5)) - 18 was tested by combining correlation and agreement statistics. Then, the sample was split into two sub-samples for the construction of BAIp. A regression was used to compute the prediction equation for BAIp-based percentage of body fat (%BF). RESULTS: The initial BAI over-estimated the %BF of children by 49% (29.6 ± 4.2% versus 19.8 ± 6.8%; p < 0.0001). The original methodology led to a BAIp = (Hip circumference/Height(0.8)) - 38 in children. When compared to BAI, BAIp showed both better correlation (r = 0.57; p < 0.01 versus r = 0.74; p < 0.0001) and agreement (ICC = 0.34; [95% CI = -0.19-0.65] versus ICC = 0.83; [95% CI = 0.81-0.84]). However, there were some systematic biases between the two values of %BF as exemplified by the large 95% limit of agreement [-9.1%; 8.8%] obtained. CONCLUSION: BAI over-estimates the %BF in children. In contrast, BAIp appears as a new index for children's body fatness, with acceptable accuracy. In its current form, this index is valid only for large-scale studies.

Level of physical activity among children and adolescents in Europe: a review of physical activity assessed objectively by accelerometry.

This study explored the proportion of European youth who are sufficiently active according to physical activity (PA) recommendations, based exclusively on objective assessment through accelerometers. A systematic electronic search of studies published up to March 2012 was conducted. PubMed was used to identify accelerometry-assessed PA studies that involved European youth. Within the 131 European studies, only 35 clearly reported the proportion of youth meeting the PA recommendations. Different thresholds lying between 1000 and 4000 counts/min (cpm) were used to define moderate-to-vigorous PA (MVPA). Overall, up to 100% of youth may be sufficiently active when using a threshold of approximately >1000-1500 cpm. With the most cited cut-off point (i.e. >2000 cpm), up to 87% of European youth might be considered physically active with reference to the current recommendations. Alternatively, with a cut-off point >3000 cpm, no more than 3-5% of them appeared to achieve these recommendations. The large discrepancy in outcomes released by accelerometer data is mainly due to the variety of cut-off points for MVPA among youth, hindering the definition of a clear goal towards PA promotion in Europe. Standardization of methods is urgently required.

Does biological maturity actually confound gender-related differences in physical activity in preadolescence?

AIM: To examine: (i) if maturity-related gender differences in moderate-to-vigorous physical activity (MVPA) depend on how maturity status is defined and measured; and (ii) the influence of maturity level on compliance with PA recommendations. METHODS: The study involved 253 children (139 boys) aged 9.9 ± 0.9 years, with mean stature and weight of 1.39 ± 0.08 m and 35.8 ± 8.8 kg respectively. Their PA was evaluated using an Actigraph accelerometer (Model 7164). Maturity was assessed using the estimated age at peak height velocity (APHV) and a standardized APHV by gender (i.e. centred APHV). RESULTS: Boys engaged in significantly more MVPA than girls (P < 0.0001). There was a significant correlation between the centred APHV and MVPA in boys (r = 0.20; P = 0.016), but not in girls (r = 0.13; P = 0.155). An ancova controlling for the estimated APHV showed no significant interactions between gender and APHV, and the main effect of gender on MVPA was negated. Conversely, there was a significant main effect of APHV on MVPA (F 1,249 = 6.12; P = 0.014; η p (2) = 0.024). Only 9.1% of children met the PA recommendations, including 14.4% of boys and 2.6% of girls (P < 0.01). This observation also applies in both pre-APHV (12.7% of boys vs. 2.4% of girls, P < 0.001) and post-APHV children (23.8% of boys vs. 3.4% of girls, P < 0.0001). No differences in PA guidelines were observed between pre-APHV and post-APHV children. CONCLUSIONS: Among prepubescent children, the influence of biological maturity on gender differences in PA may be a function of how maturity status is determined. The most physically active prepubescent children were those who were on time according to APHV.

[Differential role of physical activity and diet in the prevention of childhood obesity: pre-eminence of physical activity]. / Rôle différentiel de l'activité physique et de l'alimentation dans la prévention de l'obésité infantile: prééminence de l'activité physique.

The current theory, known as the "theory ofenergy balance", perceives paediatric obesity, like adults' obesity, as the result of an excessively positive energy balance. Thus, prevention endeavours have focused on controlling calories intake and dietary education, with increases in physical activity (PA) having just a supporting role. Paradoxically, preventive programmes developed with this vision are not satisfactory, whereas some recent findings suggest, that in the growing body of youths, PA may stimulate stem cells to differentiate preferentially into lean tissue. These observations advocate the emergence of a new theoretical framework to childhood obesity prevention: the "developmental theory", which posits the pre-eminence of PA. As a result, preventive strategies that would emphasise vigorous PA rather than food intake control can help youths develop lean bodies, at the same time that they ingest sufficient amounts of the energy and accompanying nutrients needed for a healthy growth.

[How to use motion sensors in a pediatric clinic?]. / Comment utiliser les moniteurs de mouvement en clinique pédiatrique?

Physical activity is a key construct for growth, development and maturation of children. Regular physical activity contributes to the prevention of a number of chronic diseases and their risk factors already present from an early age. Thus, physical activity counseling should be included into the routine of pediatricians. This involves a detailed assessment of different dimensions of physical activity and its associated behaviors. Indeed, the relevance of any clinical decision also depends on the performance of the tools used to evaluate targeted parameters, including physical activity. To assess physical activity of children, the use of motion sensors (pedometers and accelerometers) proved to be a good compromise between validity, reliability, accuracy and cost. However, the use of motion sensors also raises some practical problems because of complex technologies, and especially the lack of instant results. One way to overcome this shortcoming would be to outsource the assessment of movement behaviors by developing a partnership with dedicated structures. In practice, if pedometry seems appropriate for the promotion of physical activity in children, accelerometry seems more efficient for an accurate and comprehensive diagnosis, providing rich information on the overall profile of a child. The fact remains that in paediatric setting, taking into account the child-reported outcomes still important to guide the practitioner in both analyses and any necessary therapeutic decision.

[Physical activity of schoolchildren in France. The paradox of a public health priority!]. / Activité physique de l'enfant scolarisé en France. Le paradoxe d'une priorité de santé publique!

BACKGROUND: For their health and an appropriate development, it is recommended that schoolchildren get on a daily basis a minimum of 60 min of moderate-to-vigorous physical activity (MVPA). With only about 11% of girls and 25% of boys completing these recommendations, French children are among the least active in the world. In addition, most of them spend almost 3h/day in front of a screen while it is generally suggested to limit children's screen time to less than 2h/day. METHODS: An inspection of available opportunities in the French context reveals many occasions for sufficient physical activity at school, at home, in the neighbourhood, and during commuting to and from school. RESULTS: Available opportunities which encompass about 245 min/day, could contribute to at least 100 min/day of MVPA to all children, considering sport as a subsidiary and economically constraint opportunity. Moreover, in France there is an interesting legal background and political willpower to promote physical activity in the general population, and especially among children. Several factors may explain the high level of physical inactivity among French children, including the lack of investments for strategies aiming to uphold physical activity when compared to other major risks of diseases such as smoking or alcoholism. Furthermore, there may be a failure of the main actors (e.g., parents, teachers, health, sport and physical activity professionals) directly involved in the promotion of physical activity in children. Given its influence on many dimensions of a child's health, it is necessary that adults' attitudes towards physical activity and sedentary lifestyles change more quickly. CONCLUSION: It is important to increase awareness of the adult population, in that education/knowledge, role modelling, encouragement and counselling in physical activity undertaken by trained professionals are of paramount value for the integration of physical activity as part of the children's routine. These actions should be based on an accurate assessment/surveillance system and an adequate characterization of physical activity profiles of children.

[The determinants of habitual physical activity (HPA) in children: update and implications for care and prevention options in pediatric overweight/obesity]. / Actualité sur les déterminants de l'activité physique habituelle (APH) de l'enfant : mise à jour et implications pour les options de prise en charge et de prévention du surpoids/obésité infantile.

With the steady rise in the prevalence of overweight/obesity and its comorbidities in the pediatric population, it seems necessary to watch and stimulate the engagement of a majority of children in a regular physical activity. To do this, it seems crucial to know and handle properly the determinants or influences of the habitual physical activity (HPA) of children, especially when it is about overweight/obesity children. This article is an update and a review of existing data on the determinants of HPA with reference to overweight/obesity in childhood. Current data suggest that self-efficacy and physical competence are key motivators and solid anchor points for the initiation and engagement of children in a regular physical activity. In particular, for overweight/obese children, intervention strategies should first concentrate on improving these psychosocial dimensions around which other physiological components (capacity factors) and environmental (reinforcement factors) could revolve. These strategies should involve a multidisciplinary professional team (epidemiologists, actiphysists, teachers, physicians, psychologists, urban planners, local councillors) not only pursuing the same objective but with sufficiently varied skills to be effective at their respective levels.