Objective To evaluate acute changes in measures of (1) Symptom Severity Score (2) Cervical spine strength (3) and Buffalo Concussion Treadmill Test (BCTT) following concussion and throughout recovery.

Design Prospective cohort study

Setting Primary Care Centre, Dublin, Ireland

Participants 135 male Senior Cup schoolboy rugby union players [16.7(±0.8)] from 5 schools.

Interventions (or Assessment of Risk Factors) N/A

Outcome Measures Participants completed the Sport Concussion Assessment Tool (SCAT3), cervical spine maximal strength testing (Newtons/kilogram) and BCTT at pre-season, acutely following concussion and weekly to the time of medical clearance to return to rugby.

Main Results Of the 135 participants included in this study, 16 were diagnosed with a sport-related concussion (defined as per the consensus on concussion in sport) [Incidence rate= 11.85/100 players/season (95% CI; 6.9, 18.5)]. SCAT3 symptom severity scores increased from baseline to week one post-concussion by a median of 11.00 (95%CI; 7.0,30.5)(z=3.184,p=.001, n=14). Post injury to symptom burden scores decreased a median of 16.0 (95%CI;-46.0, -6.0)(z=2.81,p= <.005, n=11) points. The median change in composite neck strength score (n/kg) from baseline to post-concussion was -1.08n/kg (95%CI;-1.89, -0.54)(z=2.79, p=.005, n=14); and post-concussion to recovery increased a median of 1.79n/kg, 95%CI (-0.13,2.27)(z=2.31, p=.021, n=9). BCTT MAX HR from baseline to post-concussion decreased a median of 40.0bpm (95%CI; -72.0, -9.0)(z=-3.08, p=.002, n=14) and from post-concussion to recovery increased a median of 40.0bmp (95%CI; 23.0,91)(z+2.52, p=.012, n=8).

Conclusions Symptom burden, cervical spine strength and BCTT outcomes all worsened following concussion and improved from initial post injury scores to the time of clearance.