2.1. Participants and Procedures

A total of 277 people, mainly from the Beijing area, participated in this study, including 187 athletes (mean age = 20.44 years, SD = 0.85, ranging from 18 to 23; 91 females, 96 males) and 90 non-athletes who reported having nightmare experiences (mean age = 20.34 years, SD = 1.65, ranging from 18 to 26; 52 females, 38 males). Participants were recruited through personal contacts or coaches/teachers and volunteered to participate in this research survey. The athletes were involved in various sports, with 44 in team sports (e.g., basketball, volleyball) and 143 in individual sports (e.g., gymnastics, swimming); their average training years were 9.12 years (SD = 3.27), and all of them had national-level athlete certificates (second level, first level, or elite level). All participants had received or were receiving undergraduate education.

Participants were required to complete the survey through an internet link and were unaware of the purpose of the study. Informed consent was obtained from all participants before undertaking the study. The study was conducted following the principles of the Declaration of Helsinki and was approved by a local ethics committee (Ethical Approval Document No. 2020156H-1).