Objective: To investigate whether there is a nonlinear relationship and threshold effect between the number of daily steps counts and fat loss in obese children and adolescents. Methods: Forty eight obese children and adolescents were randomly recruited to undergo 4 week closed exercise training during July to August 2021. Actigraphy GT3X+ was used to monitor the daily steps, and fat loss effect was evaluated by changes of body composition indicators before and after the intervention. Paired samples t test was used to compare the indicators before and after the intervention; the dose response relationship between daily steps counts and fat loss was analyzed by linear regression and piecewise regression, and the nonlinear relationship was analyzed by restricted cubic spline (RCS). Results: Body fat mass, percentage of body fat, lean body mass and skeletal muscle mass decreased (27.50± 7.33 )kg, (36.17±5.59)%, (47.55±6.48)kg, (26.14±3.84)kg, respectively compared with those before intervention[(31.97± 7.82 )kg，(39.06±5.12)%，(49.08±6.93)kg，(27.08±4.15)kg] ( t=21.04, 13.32, 7.65, 8.35, P <0.05). There was a significant nonlinear doseresponse relationship between daily steps counts and the change of these indicators ( P <0.05). After adjusting for age, sex and baseline BMI, each 1 000 step increase in daily walking number, BMI increased by 0.44(95% CI =0.03-0.84)kg and body fat percentage by 0.61%(95% CI =0.17%-1.04%). After adjusting for age, sex, and baseline BMI, each 1 000 step increased in daily number of steps occurred when the daily number of steps ranged from 8 300 to 11 400, lean body weight increased by 0.58(95% CI =0.11-1.04)kg, skeletal muscle mass increased by 0.29(95% CI =0.03-0.54)kg. Conclusion There is a non linear dose response relationship between daily steps and fat loss in obese children and adolescents, for optimal fat loss efficiency, daily steps to 8 300-11 400 appropriate.

ObjectiveTo study the current status and development trend of research on the executive function in overweight or obesity， and to grasp the research hotspots in this field. MethodsA total of 1 321 literatures relevant to the executive function in overweight or obesity collected in Web of Science Core Collection database from 2010 to 2021 were selected. CiteSpace and VOSviewer were used to generate knowledge graphs for visualization analysis， then the number of articles issued， countries/regions， institutions and the co-occurrence， clustering and burst of keywords were analyzed. Results①In terms of the trend of the number of articles issued from 2010 to 2021， the annual quantity of published articles about the executive function in overweight or obesity presented a rapid growth over 2010-2014， then entered into a slow growth stage over 2014-2017， and emerged a rapid growth over 2017-2021. ②From the perspective of countries / regions， a total of 64 countries and regions participated in the research. The largest number of articles issued in this field was the USA， which had the most frequent cooperation and exchanges with other countries and regions， and exerted the greatest academic influence， occupying the core position of this research field. ③From the perspective of research institutions， a total of 1 627 institutions participated in this research field， among which the Illinois University published the most papers and closely cooperated with many productive institutions， forming a research group with a certain scale. ④From the perspective of keywords， the research content mainly involved dietary behavior research， prevention and intervention research， risk factor assessment， and analysis of the characteristics of different groups. ConclusionResearches on executive function in overweight or obesity have been developing rapidly， attracting international attention and covering a wide range of areas.