Clinical trials

The goal of this randomized clinical trial is to learn whether an individualized rowing training program based on ventilatory thresholds can improve aerobic capacity and 2,000 m rowing performance in youth rowers from Valdivia, Chile. The study will include male and female rowers aged 14 to 18 years who train regularly at Club de Remeros Arturo Prat. The main questions it aims to answer are: Does ventilatory threshold-based individualized training improve maximal oxygen uptake compared with the usual club training program? Does ventilatory threshold-based individualized training improve 2,000 m rowing ergometer performance compared with the usual club training program? Researchers will compare an individualized training group with a usual training group to see if prescribing exercise intensity based on each rower's ventilatory thresholds produces greater improvements in aerobic capacity, rowing performance, and related physiological measures. Participants will: Complete baseline and post-intervention assessments, including a cardiopulmonary exercise test on a rowing ergometer, blood lactate measurements during an incremental rowing test, a 2,000 m rowing ergometer test, body composition assessment, and respiratory muscle strength testing. Be randomly assigned to either an individualized training group or a usual training group. Complete a 12-week rowing training program. Use heart rate monitors during study training sessions so that training intensity, adherence, and safety can be monitored. Report any discomfort, injuries, or adverse events during the study. The individualized training group will train according to heart rate zones derived from each participant's ventilatory thresholds measured at baseline. The usual training group will continue the club's regular training program. The study will also explore individual variability in training response and the proportion of participants who respond or do not respond to each training approach.

This study proposes a single-blind randomized clinical trial designed to evaluate the effects of high-intensity interval training (HIIT) on liver health in adults with overweight or obesity, while also assessing the usefulness of FibroScan as a tool for detecting and monitoring hepatic changes. The study is grounded in the idea that HIIT may improve liver status in individuals with metabolic dysfunction-associated steatotic liver disease, even in the absence of major weight loss, and that FibroScan could serve not only as a diagnostic method but also as a follow-up instrument during conservative treatment. The sample will include 30 adults from the Los Ríos Region, aged 18 to 59 years, with BMI \>25 kg/m² and chronic noncommunicable conditions such as dyslipidemia, diabetes, or hypertension, provided they are fit for exercise. Participants will be randomly assigned to either an intervention group (HIIT, n=15) or a non-trained control group (n=15). Recruitment will be community-based, using posters and social media, and eligibility will be screened with the PAR-Q+ questionnaire. Individuals with excessive alcohol intake, liver disease of other etiologies, pregnancy, or contraindications to exercise will be excluded. The HIIT intervention will last 8 weeks, with 2 to 3 sessions per week, each session lasting 30 minutes. The protocol consists of five 2.5-minute bouts at 80% of heart rate reserve, interspersed with 2.5-minute active recovery periods at 20% of heart rate reserve. The training will be supervised by a physical therapist experienced in cardiometabolic exercise prescription, and the control group will receive training after the study is completed for ethical reasons. Before and after the intervention, participants will undergo a comprehensive evaluation including blood sampling, anthropometry, body composition, and physical fitness assessment. Blood markers will include transaminases, lipid profile, glucose, and HbA1c. Liver health will be assessed by FibroScan through controlled attenuation parameter (CAP) for steatosis and liver stiffness for fibrosis. Additional variables such as waist circumference, muscle mass, fat mass, handgrip strength, and prior physical activity level will also be recorded. Statistically, the study will compare baseline differences between groups and evaluate pre-post changes after the intervention using parametric or nonparametric tests according to data distribution, along with correlation and multiple regression analyses. The expected outcome is that HIIT will improve liver-related parameters, and that FibroScan will be sensitive enough to detect these changes, supporting its value as a regional clinical tool for the identification and follow-up of hepatic steatosis and fibrosis in people with overweight or obesity.

The goal of this clinical trial is to evaluate whether different physical exercise and mind-body interventions can improve executive functions and reduce stress in first-year university students. The study focuses on healthy undergraduate students, men and women, aged approximately 18-25 years, enrolled in the first year of health-related programs at a Chilean university. The main questions it aims to answer are: Do high-intensity dual-task physical exercise interventions improve executive functions (working memory, inhibitory control, and cognitive flexibility) and reduce stress in university students? Do mind-body exercise interventions (Tai Chi) reduce stress levels, measured through self-report and psychobiological biomarkers (cortisol)? Are there differential effects between high-intensity dual-task exercise, low-to-moderate intensity mind-body exercise, and cognitive stimulation on executive functioning and stress-related outcomes? Researchers will compare: * high-intensity dual-task exercise group, * low-to-moderate intensity mind-body exercise group (Tai Chi), and * cognitive stimulation control group, To determine whether physically integrated motor-cognitive training produces greater improvements in executive functions and stress biomarkers than mind-body exercise or cognitive stimulation alone. Participants will: Complete baseline pre-intervention and post-intervention assessments, Neuropsychological tests of executive functions (working memory, inhibitory control, cognitive flexibility), Self-reported academic stress questionnaires, Psychobiological measures of stress (hair cortisol, salivary cortisol), Physical activity, anthropometric, and sociodemographic assessments. Participate for 12 weeks (22 sessions, twice per week) in one of the following interventions: High-intensity dual-task physical exercise, combining aerobic, strength, and motor-cognitive tasks; Low-to-moderate intensity mind-body exercise (Tai Chi) emphasizing mindful movement, balance, breathing, and attentional control; Cognitive stimulation sessions using a structured digital cognitive training program. All sessions will be conducted in supervised, controlled settings by trained professionals, following standardized protocols to ensure safety, consistency, and adherence.

The goal of this randomized controlled trial is to test whether the online Video-feedback Intervention to Promote Positive Parenting and Sensitive Discipline (VIPP-SD) can reduce parental burnout and improve parenting practices, in mothers of young children in Chile. The main questions it aims to answer are: * Does the online VIPP-SD increase maternal sensitivity and the use of consistent but gentle limit setting? * Does it reduce parental burnout? * Does it improve parental stress and child attachment security and reduce child conduct problems? Researchers will compare families who receive the online VIPP-SD to families in a waitlist control group with dummy treatment to see if VIPP-SD has benefits for parents and children. Participants will be mothers of children aged 11-16 months at the start of the study who report elevated levels of parental burnout. Mothers in the intervention group will: * Take part in 12 weekly online sessions with a trained intervener * Receive video-feedback on their own interactions with their child * Learn strategies to respond sensitively to their child's needs and to use positive discipline The study will also measure potential moderators such as maternal mental health, child temperament, and family sociodemographic factors.