The association between physical activity and sleep quality among adolescents: the serial mediating roles of psychological resilience and academic stress and the moderating role of peer support.

Physical activity was significantly and negatively associated with sleep quality scores (PSQI) among adolescents, with the direct association accounting for the majority of the total association.

• The direct association between physical activity and PSQI scores had a standardized coefficient of β = -0.202, accounting for 61.3% of the total association.
• Higher PSQI scores indicate poorer sleep quality, so a negative association means more physical activity was linked to better sleep quality.
• The study sample consisted of 1,347 high school students from four districts in Shanghai.
• Gender, grade level, household registration type, and only-child status were controlled for in analyses.

Physical activity was indirectly associated with sleep quality through psychological resilience as a mediator.

• The indirect association through psychological resilience alone had a standardized coefficient of β = -0.053, accounting for 16.0% of the total association.
• Physical activity was positively associated with psychological resilience.
• Psychological resilience was negatively associated with PSQI scores, indicating higher resilience was linked to better sleep quality.
• Psychological resilience was measured using the Resilience Scale for Chinese Adolescents.

Physical activity was indirectly associated with sleep quality through academic stress as a mediator.

• The indirect association through academic stress alone had a standardized coefficient of β = -0.040, accounting for 12.1% of the total association.
• Physical activity was negatively associated with academic stress.
• Academic stress was positively associated with PSQI scores, indicating higher stress was linked to poorer sleep quality.
• Academic stress was measured using the Academic Stress Questionnaire for Middle School Students.

Physical activity was indirectly associated with sleep quality through the serial sequence of psychological resilience followed by academic stress.

• The serial indirect association through psychological resilience and then academic stress had a standardized coefficient of β = -0.035, accounting for 10.6% of the total association.
• This serial mediation pathway suggests physical activity enhances psychological resilience, which in turn reduces academic stress, which in turn improves sleep quality.
• Serial indirect-association analysis was conducted using PROCESS 4.2.
• The four pathways together (direct, and three indirect) accounted for the total association between physical activity and PSQI scores.

Peer support moderated the association between academic stress and sleep quality, with the positive association between academic stress and poor sleep being weaker among adolescents with higher peer support.

• Higher peer support buffered the detrimental association between academic stress and sleep quality (PSQI scores).
• Peer support was measured using the Peer Support subscale of the Perceived Social Support Scale.
• Moderation analysis was conducted using PROCESS 4.2.
• This moderation effect indicates peer support serves as a protective factor against the negative sleep consequences of academic stress.

Psychological resilience was negatively associated with both PSQI scores and academic stress among adolescents.

• Higher psychological resilience was linked to lower academic stress and better sleep quality.
• This suggests psychological resilience may partially explain why physical activity is associated with lower academic stress.
• These associations were identified through Pearson's correlation analysis and hierarchical regression analysis.
• The cross-sectional design means these should be interpreted as statistical associations rather than causal or temporal relationships.

The study used a cross-sectional design with 1,347 high school students from Shanghai completing paper-and-pencil questionnaires measuring five key constructs.

• Participants were recruited from four districts in Shanghai.
• Physical activity was measured using the Physical Activity Questionnaire for Adolescents.
• Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI).
• Covariates included gender, grade level, household registration type, and only-child status.
• Statistical analyses included Pearson's correlation, hierarchical regression, serial indirect-association analysis, and moderation analysis using SPSS 26.0 and PROCESS 4.2.