Mindfulness + Physical Activity for ACL Reconstruction

(Mind in Motion Trial)

The goal of this clinical trial is to learn whether a 6-week mobile-delivered intervention combining mindfulness meditation (Headspace) and personalized, wearable-derived physical activity goals (Oura Ring) can be feasibly delivered to young people who are 1-5 years post-anterior cruciate ligament reconstruction (ACLR) and who have elevated fear of reinjury. The main questions it aims to answer are:

* Can the Mind in Motion intervention be implemented with acceptable rates of recruitment, retention, engagement (mindfulness session completion, Oura Ring wear), and participant-rated acceptability?

* On days following a completed mindfulness session, do participants report lower anticipated fear of movement and show higher objectively measured moderate-to-vigorous physical activity (MVPA), compared with other days?

Participants will:

* Complete two brief in-person visits (approximately 1 week apart) that frame a 6-week home-based intervention period, followed by a remote assessment 4 weeks after the intervention ends.

* Wear a research-grade activPAL accelerometer on the thigh for 7 days before and 7 days after the intervention to measure objective physical activity.

* During the 6-week intervention, complete five 10-minute Headspace mindfulness sessions per week, wear an Oura Ring daily to receive personalized daily activity goals, and complete brief twice-daily check-ins (ecological momentary assessments) about fear, mood, and activity.

* Complete standard questionnaires about injury-related fear, psychological readiness for activity, and knee function/symptoms at baseline, mid-intervention, immediately after the intervention, and at a 4-week follow-up.

* Complete a brief audio-recorded exit interview describing their experience with the intervention.

This is a single-arm, single-site feasibility study; there is no control group and no randomization. Findings will inform the design of a future multisite randomized controlled trial.