To test the safety and feasibility of a new treatment for adolescents who are slow to recover from a sport-related concussion, the investigators are conducting a randomised controlled trial comparing treatment as usual with an active rehabilitation program that involves sub-symptom threshold cardiac exertion, sport-specific coordination activities, and positive visualisation techniques.

Most adolescents recover within the first month following a sport-related concussion. However, some do not. Little is known about how to best facilitate recovery when symptoms do not resolve spontaneously and swiftly. Although active rehabilitation has been recently suggested as a promising means of promoting recovery, current literature does not provide adequate evidence for safe adaptation into clinical practice.

Objective: The purpose of this project is to evaluate an active rehabilitation protocol for adolescents who are slow to recover following sport-related concussion. Primary aims: to confirm the tolerability and safety of the active rehabilitation protocol as compared to treatment as usual controls. Secondary aims: 1) to document the impact of active rehabilitation on post-concussion symptoms and return to activity; 2) to explore the intervention effects on quality of life, mood, energy level, balance, cognitive functioning, and return to pre-injury activities.

Study design: A parallel group open label randomized comparison trial of 30 adolescents who are slow to recover following sport-related concussion. After initial screening and assessment, both groups will receive treatment as usual. Participants in the experimental group will also participate in sub-symptom threshold exercise, sport-specific coordination practice, and positive visualisation daily.

Outcome measures: The investigators will monitor for adverse events and assess post-concussion symptoms throughout the study as a primary marker of recovery. The investigators will also report secondary outcomes such as quality of life, mood, energy level, balance and cognitive functioning. Finally the investigators will record rates of return to school (full time, part time) and rates of return to sport (regular pre-injury vs. modified level). As a result, clinicians will be able to follow a new rehabilitation protocol in a safe and meaningful way. Lastly, research findings will be disseminated in the form of a publication, at conferences, and via in-services.

Hypotheses:

1a. The drop-out rate will be comparable in the groups receiving treatment-as-usual (TAU) only versus TAU plus active rehabilitation.

1b. Adverse events occurring outside of the clinic will be comparable in the groups receiving TAU only versus TAU plus active rehabilitation.

1c. For the group receiving active rehabilitation, symptom exacerbations in the in-clinic exercise sessions will resolve within 30 minutes.

2. Participants receiving active rehabilitation will report greater improvement of post-concussion symptoms (primary outcome) at follow-up.

3. Participants receiving active rehabilitation will report higher quality of life, fewer depressive symptoms, and higher energy levels; demonstrate better balance and neuropsychological performance at follow-up; and return to their pre-injury activities at higher rates.

Adolescents referred to G. F. Strong Rehabilitation Centre (GFS) for atypical recovery preventing them from entering standard return to activities protocols will be recruited on a voluntary basis to participate in this study.

Eligibility criteria for study entry are as follows:

1. sustained an injury in sports,
2. are 4 weeks post injury,
3. report 2+ persistent post-concussion symptoms with no significant improvement over the past week,
4. are between the ages of 14 and 18,
5. have no developmental, congenital, or cognitive diagnoses,
6. have no active mental health disorders,
7. are able to attend at GFS,
8. speak English as their dominant language,
9. have no prior moderate or severe TBI,
10. have no concussion in the 6 months before the present injury, and
11. medical clearance by the study physician.