For a long time, studies on the peer effect of physical activity among adolescents have focused on relevance rather than causality. This article provides empirical evidence of the peer effect of physical activity among adolescents using data from the China Education Panel Survey. The results show that the peer effect increases physical activity by about 6.757–8.984 min per week among classmates, a finding consistent with previous studies. Using the instrumental variable approach and considering the potential missing variables, the peer effect increases physical activity by 23.923–27.410 min per week, representing a threefold increase. In addition, the general attitude towards sports in class plays a significantly influential role, accounting for 20% of the peer effect of physical activity.

Purpose: This study investigates how regional integration (RI) influences the high-quality development of the ice–snow economy (ISE) in China. It addresses a critical gap in the literature by examining spatial spillover effects and nonlinear relationships across urban clusters during the post–Winter Olympics era. Design/methodology/approach: The study constructs a multidimensional ISE index covering 207 Chinese cities from 2013 to 2024, incorporating five dimensions: industrial support, market dynamism, infrastructure, government support and environmental sustainability. It employs fixed-effects panel models and spatial Durbin models (SDMs), complemented by two-regime SDMs, to investigate the direct and indirect effects of RI, while controlling for spatial heterogeneity. Findings: Results reveal an inverted U-shaped relationship between RI and ISE, suggesting that moderate integration enhances ISE growth, while excessive integration may lead to resource crowding. Significant spatial spillover effects are identified, particularly in core–periphery structures. Dual-synergy patterns emerge in regions such as Beijing–Tianjin–Hebei and Harbin–Changchun, whereas regions including Chengdu–Chongqing exhibit growth-suppressing patterns. Service-oriented sectors demonstrate stronger spatial diffusion than manufacturing-oriented sectors. Originality/value: This study enriches the spatial economics literature by integrating nonlinear spatial spillovers and core–periphery asymmetries into the analysis of a rapidly expanding policy-driven economy. The findings offer empirical support for differentiated regional strategies and cross-regional coordination mechanisms in fostering sustainable ISE development.

Urban parks serve as important venues for promoting physical activity. This study aimed to examine the associations between both perceived and objective proximity to parks and within-park physical activity (PA) across different intensity levels among urban park users. This cross-sectional study was conducted in four urban parks in Beijing, China. A total of 399 park users completed questionnaires assessing perceived proximity, demographic characteristics, and within-park physical activity. Objective proximity was measured as Euclidean distance from participants’ residences to park centers using the Geographic Information Systems. Multilevel linear regression models were used to examine the associations between perceived and objective proximity and different intensities of within-park PA while controlling for sociodemographic covariates, with bootstrap methods employed for non-normally distributed outcomes. Moderate correspondence was found between perceived and objective proximity measures. Both proximity measures demonstrated significant negative associations with moderate-intensity PA and walking within parks, with exploratory spline analyses indicating that these associations gradually weakened at greater distances beyond approximately 1 mile. No significant associations were found between either proximity measure and vigorous-intensity PA within parks. Although both perceived and objective proximity were associated with within-park PA, these relationships varied across different intensity levels. These findings suggest that proximity may play a more important role in promoting moderate-intensity activities and walking within parks, while for vigorous-intensity activities, factors beyond park distance may be more relevant considerations.