Virtual Reality vs. Gym-Based Martial Arts Training for Aggression in Children With Conduct Disorder

This study is a three-arm, parallel-group randomized controlled trial (RCT) with baseline (T0), post-intervention (T1), and 30-day follow-up (T2) assessments. The trial is conducted in Tehran, Iran, in collaboration with child and adolescent mental health outpatient services and community counseling centers. Participants are randomly allocated in a 1:1:1 ratio to immersive VR-based martial arts training (VR-MA), club-based (real-world) martial arts training (Club-MA), or a no-exercise control group.

Randomization and Blinding:

An independent researcher generates the allocation sequence using computer-based randomization. Allocation is concealed using sequentially numbered, opaque, sealed envelopes (SNOSE) opened only after completion of the baseline assessment. Due to the nature of exercise interventions, participants and trainers cannot be blinded. However, outcome assessors and the data analyst are kept blind to group allocation. Families are instructed not to disclose group assignments to assessors.

Interventions:

Both intervention arms receive an identical training dose: 24 sessions across 8 weeks (3 sessions/week), with each session lasting 40 to 60 minutes. Both groups follow a standardized session structure: a 5-10 minute warm-up (light aerobic activity and dynamic stretching), a 25-40 minute skill and conditioning block (striking drills, footwork, and progressive combination sequences), and a 5-10 minute cool-down (structured breathing exercises, static stretching, and guided reflection emphasizing behavioral norms such as respect and self-discipline).

VR-MA Group:Participants use standalone Meta Quest 3S head-mounted displays (Meta Horizon OS) in a supervised indoor setting. Training content emphasizes combat sport simulation and target-based striking drills delivered through commercial applications (e.g., LES MILLS BODYCOMBAT, FitXR). The protocol emphasizes coach-led pacing, technique accuracy, and self-regulation, deliberately excluding external reward systems or gamification.

Club-MA Group: Training is delivered in a martial arts club setting under the supervision of two certified kickboxing/martial arts instructors. The protocol is standardized and progressive. The first three sessions introduce basic stances, guards, and fundamental punches/kicks. Subsequent sessions emphasize controlled combinations, footwork, and structured drills (e.g., bag work, pad/mitt drills). Verbal exhalation cues are used to coordinate breathing and movement.

Control Group: Participants do not receive any additional organized physical activity during the 8-week period. Families are instructed to maintain usual routines and refrain from starting new structured martial arts or VR training programs.

Safety Monitoring:

Participant safety is continuously monitored by trained staff. For the VR-MA group, children are screened for prior severe motion sickness, and staff monitor for nausea, dizziness, headache, distress, or unsafe movement patterns. Rest breaks are allowed, and sessions are paused or stopped if symptoms emerge. Headsets are sanitized between uses. All training sessions are offered free of charge, and basic sports attire is provided. Retention efforts include reminder calls to caregivers and flexible scheduling. Any adverse events or participant withdrawals are systematically documented and reviewed by the study coordinator.

Statistical Analysis Plan:

Analyses are conducted using SPSS (v29). Descriptive statistics are computed for each group at all time points. Assumptions are evaluated using Kolmogorov-Smirnov and Shapiro-Wilk tests for normality, and Levene's test for homogeneity of variance. The primary hypothesis-testing approach uses a mixed-design repeated-measures model (GLM) with Group (Control vs. VR vs. Gym) as the between-subject factor and Time (T0 vs. T1 vs. T2) as the within-subject factor. The Group × Time interaction is the main indicator of differential change across arms. Sphericity is assessed with Mauchly's test; when violated, Greenhouse-Geisser corrections are applied. Baseline-adjusted ANCOVA models are run separately for T1 and T2, with the corresponding baseline score (T0) entered as a covariate. For secondary outcomes (four subscales), multiplicity is controlled using Holm-Bonferroni adjusted p-values. Effect sizes are reported as partial eta squared (η²p).

Participants complete the standardized training program using a standalone virtual reality headset (Meta Quest 3S) within a supervised indoor setting. The training content emphasizes combat sport simulation and striking practice, including boxing-style engagements and target-based striking drills. Commercial applications are used to deliver structured, graded-intensity sessions. The training emphasizes coach-led pacing, technique accuracy, and self-regulation without external reward systems.

Behavioral: Immersive VR-Based Martial Arts Training

Participants receive the same training dose and session structure, delivered in a martial arts club setting under the supervision of two certified kickboxing/martial-arts instructors. The protocol is standardized and progressive, introducing basic stances, guards, and fundamental punches/kicks in the first three sessions. Subsequent sessions emphasize controlled combinations, footwork, and structured drills, including bag work and pad/mitt drills.

Behavioral: Club-Based Martial Arts Training

Participants do not receive any additional organized physical activity throughout the study during the 8-week period. Families are instructed to maintain their usual routines and to refrain from starting new structured martial arts or VR training programs during the trial.

An 8-week training program (24 sessions, 40-60 minutes per session) using Meta Quest 3S head-mounted displays. Delivered via commercial VR applications (e.g., LES MILLS BODYCOMBAT, FitXR) emphasizing combat sport simulation, striking practice, and target-based drills. Structure includes warm-up, skill/conditioning block, and cool-down with breathing exercises. No external gamification or reward systems are used.

An 8-week training program (24 sessions, 40-60 minutes per session) delivered in a martial arts club setting. Supervised by two certified instructors. Includes warm-up, skill/conditioning block (striking drills, footwork, bag/pad work), and cool-down with breathing exercises and guided reflection on behavioral norms.

Plazo: Baseline (T0), Post-Intervention (T1, Week 8), and 30-Day Follow-Up (T2)

Aggression is measured using the Children's Aggression Questionnaire (CAQ). The CAQ is a multidimensional instrument assessing overall aggression and four subscales: verbal aggression, physical aggression, relational aggression, and anger/impulsive tension. Higher scores indicate greater severity of aggression.

Plazo: Baseline (T0), Post-Intervention (T1, Week 8), and 30-Day Follow-Up (T2)

Individual subscale scores derived from the Children's Aggression Questionnaire (CAQ): verbal aggression, physical aggression, relational aggression, and anger/impulsive tension. Higher scores indicate greater severity in each domain.

Comparing Virtual Reality and Gym-Based Martial Arts Training for Aggression Reduction in Children With Conduct Disorder: A Three-Arm Randomized Controlled Trial