Healthy Adolescents

This randomised controlled trial will evaluate the effects of integrating a standalone mixed-reality (MR) breathing and eye-gaze training intervention (EyeBreathe) into regular basketball practice for adolescent athletes in Latvia. Participants will be individually randomised to either a six-week MR intervention (two sessions per week) or to continue usual training. Assessments before and after the intervention will measure heart rate and heart rate variability, CO₂ tolerance, breathing pattern, reactive stress tolerance, and pre-competition anxiety. Sessions will be supervised at first, then completed independently via password-protected headset profiles. Intervention adherence will be monitored. The primary efficacy analysis will use a prespecified per-protocol population, defined as intervention participants who complete at least four of the twelve scheduled sessions.

The goal of this clinical trial is to evaluate the quality and duration of the immune response against chikungunya virus elicited by the IXCHIQ® vaccine in healthy adults and adolescents. The main questions it aims to answer are: Is the cellular immune response elicited by IXCHIQ® adequate for Chikungunya prevention? Is the IXCHIQ® vaccine safe? How does the immune response elicited by IXCHIQ® behave at the different time points evaluated? Participants will: Receive the IXCHIQ® vaccine; Be evaluated by medical personnel and have a blood sample taken on days 3, 7, 30, 180, and 720 after vaccination; Be contacted by phone 60 days after vaccination.

The purpose of this study is to examine the effects of a digital literacy program on problematic internet use, emotion regulation, and loneliness among adolescents. The study aims to answer the following key questions: * Does a digital literacy program for adolescents affect problematic internet use, emotion regulation skills, and loneliness? * What is the effect of a digital literacy program for adolescents on the level of problematic internet use? * What is the effect of a digital literacy program for adolescents on emotion regulation skills? * What is the effect of a digital literacy program for adolescents on loneliness? Researchers will conduct pretest and posttest evaluations in the experimental and control groups to determine the effects of the digital literacy program on problematic internet use, emotion regulation, and loneliness in adolescents. Participants in the experimental group who meet the inclusion criteria will receive 8 weeks of positive youth development-based digital literacy training, 40 minutes per week. After the posttest measurements are completed, the intervention group will receive 2 weeks of digital literacy training.

This cross-sectional study aims to determine the test-retest reliability of surface electromyography (sEMG) outcomes in detecting levels of fatigue among healthy adolescents engaged in physical activities. It seeks to evaluate the consistency of sEMG parameters across two test sessions and correlate these measurements with both performance metrics and subjective fatigue assessments. Participants will perform repetitive squatting until volitional exhaustion while their muscular activity is recorded. They will do so on two different test sessions with an interval of one week in between.