Safety and Prognostic Utility of Provocative Exercise Testing in Acutely Concussed Adolescents: A Randomized Trial

Abstract

Objective: To evaluate (1) systematic assessment of exercise tolerance in adolescents shortly after sport-related concussion (SRC) and (2) the prognostic utility of such assessment.

Design: Prospective randomized controlled trial.

Setting: University and community sports medicine centers.

Participants: Adolescents with SRC (1-9 days from injury). Sixty-five were randomized and 54 completed the study (mean age 15 years, 4 days after injury).

Interventions: Buffalo Concussion Treadmill Test (BCTT, n = 27) or not (controls, n = 27) on visit day #1. Heart rate threshold (HRt) at symptom exacerbation represented level of exercise tolerance. Participants reported symptoms daily for 14 days and then had follow-up BCTT (n = 54). Recovery was defined as returning to normal level of symptoms and exercise tolerance, verified by independent physician examination.

Main outcome measures: Days to recovery and typical (≤21 days) versus prolonged recovery (>21 days). Mixed effects linear models and linear regression techniques examined symptom reports and time to recovery. Linear regression assessed the association of HRt with recovery time.

Results: Days to recovery (P = 0.7060) and typical versus prolonged recovery (P = 0.1195) were not significantly different between groups. Symptom severity scores decreased in both groups over 14 days (P < 0.0001), were similar (P = 0.2984), and did not significantly increase the day after the BCTT (P = 0.1960). Lower HRt on visit day #1 was strongly associated with prolonged recovery time (P = 0.0032).

Conclusions: Systematic evaluation of exercise tolerance using the BCTT within 1 week after SRC did not affect recovery. The degree of early exercise intolerance after SRC was important for prognosis. This has implications for school academic and team preparation.

Conflict of interest statement

The authors report no conflicts of interest.

Figures

Figure 1

Study Design

Figure 2

The sample mean (solid lines), 5th and 95th sample percentiles (dashed lines) for each day's symptom severity scores for the BCTT group (black) and the control group (red).