To investigate the impact of extracurricular physical activity on heart rate variability (HRV) among primary and secondary school students in Chengdu City, so ao to provide references for scientific exercise prescription.

Using a convenient sampling method, 1 323 primary and secondary students were enrolled from central Chengdu who underwent physical fitness assessments at Sichuan Provincial Institute of Sports Science from September 2020 to January 2022. According to the standards of the National Physical Fitness Monitoring Center, boys and girls were divided into groups with and without extracurricular physical exercise habits. HRV was monitored using the SA-3000P device. Key HRV parameters were evaluated separately by gender, including standard deviation of normal-to-normal intervals (SDNN), root mean square of successive differences (rMSSD), total power (TP), low-frequency power (LF) and high-frequency power (HF). Statistical analyses were employed by t-test, Mann-Whitney U-test and Chi-square test.

lgSDNN, lgrMSSD, TP, LF and HF in the group without extracurricular physical exercise habit [boys: (1.67±0.13)ms, (1.59±0.20)ms, (7.34±0.73)ms², (6.11±0.74)ms², (6.05±0.87)ms²; girls: (1.67±0.13)ms, (1.59±0.19)ms, (7.35±0.60)ms², (6.06±0.69)ms², (6.12±0.87)ms²] were lower than those in the group with extracurricular physical exercise habit [boys: (1.75±0.13)ms, (1.72±0.18)ms, (7.69±0.62)ms², (6.41±0.76)ms², (6.44±0.79)ms²; girls: (1.73±0.13)ms, (1.68±0.20)ms, (7.60±0.65)ms², (6.26±0.86)ms², (6.36±0.90)ms²] (t=-8.24, -8.75, -6.54, -5.35, -6.33;-5.10, -4.90, -4.47, -2.71, -2.93, all P < 0.01). Only the group of boys without extracurricular physical exercise habits showed a decrease in lgLF/HF [0.04(-0.19, 0.27)] compared to the group with extracurricular physical exercise habits [-0.03(-0.25, 0.20)] (Z=-2.01, P < 0.05). When the score classes of autonomic nerve activity, stress index and fatigue index were compared between boys and girls groups without and with extracurricular physical exercise habits, the proportion of boys normal and above scores increased from 79.3%, 84.1%, 71.8% to 91.4%, 95.7%, 87.3%, respectively, and the differences were statistically significant (χ²=47.42, 63.66, 38.28); the proportion of girls normal score and above increased from 79.8%, 85.7%, 75.0% to 85.4%, 92.1%, 79.4%, and the differences were statistically significant (χ²=48.31, 22.18, 22.22) (all P < 0.01).

The primary and secondary school students who have the habit of extracurricular physical exercise have enhanced compliance in indicators related to HRV, showing more complex heart rate variability.

To explore the relationship between positive parenting styles and academic emotions in junior high school students, as well as the chain mediation effects of parent-child communication and peer relationships, providing a theoretical basis for family education interventions.

Using stratified cluster random sampling, 1 063 students from four junior high schools in a city in Anhui Province were selected for questionnaire surveys, form March to April, 2025. Core variables were measured using the Short-form Parenting Style Scale, Adolescent Parent-Child Communication Scale, Peer Relationship Scale, and Adolescent Academic Emotion Questionnaire. Group comparison was conducted using t-test or analysis of variance, and Pearson correlation analysis was used to examine the correlation between positive parenting styles, peer relationships, parent-child communication and positive academic emotions. Multiple linear regression analysis was used to examine the effects of positive parenting styles, peer relationships and parent-child communication on positive academic emotions. A mediation effect model and Bootstrap method were employed to test the chain mediation effects.

Students who were class leaders, had parents with higher education levels, or came from intact families scored significantly higher on positive academic emotions (t/F=7.23, 13.73, 10.67, 4.45, all P < 0.01). Positive parenting styles, peer relationships, and parent-child communication were all positively correlated with positive academic emotions (r=0.45, 0.41, 0.38), and all three positively predicted positive academic emotions (β=0.24, 0.23, 0.12) (all P < 0.01). Further analysis showed that positive parenting styles directly predicted positive academic emotions (β=0.40) and also indirectly influenced academic emotions through parent-child communication (β=0.07), peer relationships (β=0.05), and the chain mediation path of "parent-child communication → peer relationships" (β=0.04) (all P < 0.05), with the total indirect effect accounting for 40.55%.

Positive parenting styles enhance junior high school students' academic emotions through the chain mediation path of "parent-child communication → peer relationships", providing theoretical support for interventions within the educational ecosystem.

To explore the core features of trait aggression in children and adolescents, so as to provide a theoretical basis for behavioral interventions targeting the central psychological characteristics of aggression in children and adolescents.

From March to May 2020, a simple random convenience sampling method was employed to recruit 39 165 students from grades 4 to 12 in Sichuan, Chongqing, Guizhou, and Shandong. Data were collected via online questionnaires, with all participants completing the Chinese Version of the Aggression Questionnaire. Psychometric network analysis was utilized for data processing.

Trait aggression among Chinese children and adolescents was at a moderately low level. The core nodes of the network structure included physical aggression [if someone intentionally causes trouble for me, I will hit them severely (AGG6); if someone hits me, I will retaliate (AGG11)] and self-aggression [When I am very irritable, I think of hurting myself (AGG5); when I am in a bad mood, I engage in behaviors that harm my health, such as overeating (AGG25)]. Across grade levels, core nodes primarily originated from the anger dimension [When I'm angry, I feel like a powder magazine that could explode at any moment (AGG13); I can't control my temper (AGG18); I am prone to getting angry when I see things that are not pleasing to the eye (AGG23); I will get angry for no reason (AGG27)]. Except for grades 7 and 9, core nodes in other grades included the verbal aggression dimension [I am prone to arguments with people (AGG22)]. Before grade 8, core nodes incorporated the self-aggression dimension (AGG 5, AGG 25); after grade 8, core nodes included the physical aggression dimension [AGG 6, AGG 11, I fight slightly more than others (AGG16), and if people around me make things difficult for me to a certain extent, I will fight with them (AGG26)]. No statistically significant differences were found in the trait aggression network structures across grades, genders, or within-gender comparisons of different grades.

These findings broaden our understanding of aggression in children and adolescents, suggesting that behavioral interventions can effectively reduce aggressive behaviors in this population.

To explore differences in the factors influencing parents' and teachers' assessments of preschool children's mental health using the Strengths and Difficulties Questionnaire (SDQ), so as to provide reference for promoting children's mental health.

A retrospective analysis was conducted on the SDQ survey data of 14 763 middle and senior kindergarten children in Nanshan District, Shenzhen, from March to June 2023. Chi-square χ² tests were used to analyze differences in mental health assessments between parents and teachers. Multivariate Logistic regression was employed to examine the factors influencing parental assessments, and Kappa coefficients were used to evaluate the consistency between parent and teacher evaluations.

The positive rate of mental health problems reported by parents (7.2%) was significantly higher than that reported by teachers (6.2%) (χ²=254.27, P < 0.01). Gender differences revealed that parents reported a lower positive rate for boys (7.9%) compared to teachers (8.5%), whereas for girls, the parental positive rate (6.4%) was higher than that reported by teachers (3.8%) (χ²=163.59, 81.26, all P < 0.01). Age-related differences showed that parental positive rates for 4, 5, and 6-year-olds (8.5%, 7.4%, 5.8%) were consistently higher than teachers' assessments (6.3%, 6.7%, 5.4%) (χ²=41.23, 157.53, 63.67, all P < 0.05). Univariate analysis of parental assessments indicated higher positive rates among boys (7.9%), 4-year-olds (8.5%), mothers aged 20-35 (6.6%), mothers with high school education or below (9.8%), fathers aged 23-40 (6.4%), fathers with high school education or below (10.3%), and children exposed to secondhand smoke (7.9%) (χ²=23.56-235.24, all P < 0.01). Multivariate Logistic regression identified lower parental education levels and exposure to secondhand smoke as significant risk factors for abnormal SDQ assessments by parents (χ²=2.05, 1.62, 3.15, all P < 0.05). The Kappa coefficients for parent-teacher agreement across SDQ subscales and total difficulties ranged from 0.04 to 0.12 (all P < 0.01).

Parental education level and exposure to secondhand smoke are significant factors influencing preschool children's mental health. Differences exist between parental and teacher assessments of children's mental health, and incorporating teacher evaluations can provide a more comprehensive understanding of preschoolers' psychological well-being.

To analyze the longitudinal relationship between cumulative multiple risks and depressive emotions in primary and secondary school students, and to examine the mediating role of executive function in the association, so as to provide scientific evidence for preventing and alleviating depressive emotions in adolescents.

Using convenience sampling, 946 students from Shandong and Hunan provinces were tracked for one year (December 2023 to December 2024) regarding their exposure to multiple risks, executive function, and depressive emotion. Pearson correlation analysis was employed to examine variable relationships, while mediation modeling with Bootstrap testing (5 000 iterations) was conducted to verify the mediating effect.

At baseline, the prevalence of survival risks was relatively low, with 37.98% of primary school students and 30.87% of middle-school students reporting no exposure to such risks. In contrast, developmental risks and harmful risks showed substantially higher prevalence, with 63.20% of primary school students and 69.63% of middle-school students experiencing two or more risk factors in developmental risks, and 44.81% of primary school students and 71.60% of middle-school students experiencing two or more harmful risks. After controlling for gender, age, baseline executive function and depressive emotions: higher cumulative developmental risks (β=0.06, P < 0.01) and hazardous risks (β=0.08, P < 0.01) predicted elevated depressive emotion, while survival risks showed no significant prediction (β=0.03, P>0.05). Executive function significantly mediated the effects of both developmental risks (Effect=0.02, 95%CI=0.01-0.04) and hazardous risks (Effect=0.02, 95%CI=0.01-0.04) on depressive emotion (both P < 0.05).

Increased exposure to developmental and hazardous risks predicts poorer executive function, which subsequently exacerbates depressive emotions in students.

To explore the influence of social support and school connectedness on the developmental trajectory of self-efficacy in adolescents and analyze its subgroup effects, so as to provide a basis for enhancing adolescents' self-efficacy.

Using a cluster random sampling method, 930 first-year middle school students from four schools in Xiangxi Autonomous Prefecture, Hunan Province, were selected for three longitudinal surveys in October 2023 (T1), April 2024 (T2), and October 2024 (T3). The General Self-efficacy Scale (GSES), Social Support Scale (SSS), and School Connectedness Scale (SCS) were administered. Latent growth mixture modeling (LGMM) was used to identify different developmental trajectories of self-efficacy in early adolescence. Multivariate Logistic regression was employed to examine the associations of self-efficacy trajectories with social support and school connectedness in adolescents.

The developmental trajectory of self-efficacy in adolescents was classified into three categories: category 1 was low efficacy-rapid growth group (53 students, 6.6%), category 2 was moderate efficacy-stable growth group (793 students, 84.1%), and category 3 was high efficacy-rapid decline group (84 students, 9.3%). Using the low efficacy-rapid growth group as the reference, students with higher social support were more likely to belong to the moderate efficacy-stable growth group (OR=1.06, 95%CI=1.03-1.08) and the high efficacy-rapid decline group (OR=1.06, 95%CI=1.03-1.09), students with higher school connectedness were more likely to belong to the high efficacy-rapid decline group (OR=1.10, 95%CI=1.03-1.18) (all P < 0.05). Subgroup analysis revealed significant effects for boarding status (low efficacy-rapid growth group at T1, t=2.10; high efficacy-rapid decline group in social support, t=-2.15) and only-child status (moderate efficacy-stable growth group at T2, t=2.05) (all P < 0.05).

The developmental trajectory of self-efficacy in adolescents exhibits group heterogeneity, with boarding status and only-child status showing subgroup effects. Enhancing social support and school connectedness can help improve self-efficacy in adolescents.

To analyze the association between each regional fat mass and total body bone mineral density (BMD) in children and adolescents aged 7-17 years in Beijing, so as to provide theoretical basis and practical guidance for implementing interventions.

From September to December 2020, a stratified cluster random sampling method was used to select 1 423 children and adolescents aged 7-17 years in Tongzhou District, Beijing. Dual-energy X-ray absorptiometry (DXA) was employed to measure regional body composition and total body BMD. Multiple linear regression was used to analyze the association between regional fat mass and total body BMD.

The median (interquartile range) fat mass values for total body, upper limbs, abdomen, hips, and thighs were 13.51(8.84, 19.21), 1.59(1.08, 2.23), 0.73(0.39, 1.29), 2.32(1.46, 3.26), 5.29(3.59, 7.21)kg, respectively. After adjusting for covariates, the results of multiple linear regression analysis showed that total body fat mass (β=0.010), abdominal fat mass (β=-0.100), and hip fat mass (β=0.104) were significant associations with total body BMD (all P < 0.01). Sex-stratified analysis revealed that in boys, total body fat mass (β=0.008) and hip fat mass (β=0.058) were positively associated with BMD, while thigh fat mass (β=-0.038) showed a negative association with total body BMD (all P < 0.05). In girls, total body fat mass (β=0.013), hip fat mass (β=0.163), and thigh fat mass (β=0.023) were positively associated with total body BMD, whereas abdominal fat mass (β=-0.196) showed a negative association with total body BMD (all P < 0.05). Among children and adolescents with body fat percentage below the standard range, within the standard range and above the standard range, total body fat masses were positively associated with total body BMD (β=0.021, 0.016, 0.015); among children and adolescents with body fat percentage within the standard range while upper limb (β=-0.042), abdominal (β=-0.067), and thigh fat mass (β=-0.018) showed negative associations with total body BMD, and hip fat mass demonstrated a positive association with total body BMD (β=0.082) (all P < 0.05).

Regional fat distribution is associated with total body BMD in children and adolescents, with the nature of these associations varying by sex and body fat percentage.

To investigate the mental health status and related factors among primary and secondary school students in western Yunnan Province, so ao to provide scientific evidences for advancing mental health education.

In June 2024, a stratified cluster sampling method was employed to select 4 584 students from 18 schools across Diqing Tibetan Autonomous Prefecture, Lincang City and Baoshan City three regions in western Yunnan Province. The Mental Health Test (MHT) was used for assessment. Latent class analysis (LCA) and Logistic regression were applied for data classification and related factor analysis respectively.

The overall positive detection rate of MHT was 11.81%, with a mean total score of 40.50±19.25. The predominant issues were learning anxiety (58.4%), hypersensitivity tendency (31.1%), and self-blame tendency (23.1%). LCA categorized students into four groups: severe psychological problems group (74.4% detection rate), learning anxiety-hypersensitivity group (16.4%), learning anxiety-physical symptoms group (9.2%), and healthy group (0). Logistic regression revealed that compared with the healthy group, the severe problems group showed higher risks among females (OR=3.01), junior/senior high school students (OR=1.88/4.02), and those with authoritarian parenting (OR=3.54); the anxiety-hypersensitivity group had higher risks for females (OR=1.87), senior high students (OR=1.54), boarders (OR=1.31), and authoritarian parenting recipients (OR=1.85); the anxiety-physical symptoms group demonstrated increased risks among females (OR=2.22), senior high students (OR=2.58), and authoritarian parenting recipients (OR=2.74), while lower risks were observed for students with parent/grandparent guardians (OR=0.38) and non-only children (OR=0.58) (all P < 0.05).

Mental health problems are prominent among students in western Yunnan, with gender, grade level, boarding status, guardian type, and parenting style being key determinants. Recommendations include strengthening mental health education, prioritizing left-behind children's psychological well-being and promoting healthy development.

To investigate the impact of preschool children's aquatic motor skill (AMS) acquisition on their fundamental motor skill (FMS) development and the correlation between AMS and FMS development, so ao to provide a scientific basis for early childhood education and physical education teaching.

From April to June 2024, 60 children, recruited by random sampling from a kindergarten in Taiyuan, were stratified randomly divided into an experimental group (n=30) and a control group (n=30). The experimental group were further divided into five classes of six each. They received AMS practice interventions twice weekly, 40 minutes per session, over eight weeks (16 sessions total) at a designated swimming center. The control group maintained their usual routine. Children's FMS and AMS were assessed pre- and post-intervention using the Test of Gross Motor Development-3rd (TGMD3) and Actual Aquatic Skills Test (AAST), respectively. Before and after test comparisons within and between groups employed t-tests, Wilcoxon signedrank tests, ANCOVA (including ranktransformed ANCOVA), and Cohen's d effect sizes were calculated for standardized mean differences. Spearman rank correlation was used to analyze relationships between FMS and AMS.

After the aquatic learning, the experimental group scored significantly higher than the control group on locomotor skills (F=20.47, P < 0.01, η²=0.26), FMS (F=4.59, P=0.04, η²=0.08), and AMS (F=109.71, P < 0.01, η²=0.79). The experimental group's improvement in locomotor skills 5.0(3.8, 7.3) versus the control group (2.8±2.5) yielded a medium effect size (Cohen's d=0.71); AMS gains in the experimental group versus controls showed a very large effect size (Cohen's d=4.73) (both P < 0.01). Among preschool children, AMS acquisition was positively correlated with locomotor skills (r=0.39) and overall FMS (r=0.43)(both P < 0.05). Skill specific assessments revealed lower proficiency in headfirst entry (immersion), treading water, and sagittalplane rotation.

Preschool children's acquisition of AMS has a positive effect on their FMS, with mutual facilitation between the two, especially in locomotor abilities.

To investigate the timing of puberty onset among primary school students, so as to provide the reference data for early identification of children with suspected precocious puberty.

A study was conducted from October 23 to November 7, 2023, involving 10 225 students(5 412 boys, 4 813 girls) from grade 1 to 6 of four campuses in Meiling Primary School in Yangzhou. Breast development in girls and external genitalia in boys was assessed via visual inspection and palpation, with pubertal stages classified using the Tanner staging method. Puberty onset timing was determined based on age/sex reference values from Chinese Han children's pubertal milestone indicators. Descriptive analysis was performed using SPSS 26.0.

The median age for testicular volume reaching 4 mL in boys was 10.49 years, while the median age for breast development onset in girls was 9.70 years. Among boys with testicular volume ≥4 mL, 16.6%(n=217) were identified as suspected early puberty cases; among girls with Tanner stage Ⅱ and Ⅲ, 123(9.4%) and 165(18.5%) showed earlier breast development than the reference range. Overall, 14.4% of students exhibited suspected precocious puberty.

The onset age of puberty for girls in primary schools of Yangzhou aligns with findings from other regions, while boys show earlier pubertal initiation.