Abstract
Background:
While many adolescent athletes recover from concussion within one month, some will not recover within this timeframe. Concussion management guidelines have evolved to de-emphasize rest and promote early re-introduction of sub-symptomatic physical activity. However, the optimal levels of physical activity during concussion recovery have yet to be determined.
Hypothesis/Purpose:
To investigate the association between quantity, frequency and intensity of physical activity after concussion with clinical recovery, defined as return-to-play (RTP) clearance from their physician.
Methods:
We conducted an observational, prospective cohort study of 26 youth athletes who sustained a concussion and were evaluated at two time points: initial visit (<14 days post-injury) and RTP clearance visit. Participants reported concussion symptoms using the Post-Concussion Symptom Inventory (PCSI). Participants wore an activity tracking device for the first two weeks after initial visit. This allowed us to quantify average steps/day, exercise frequency (average workouts/week), exercise duration (average time/workout), and exercise intensity (average/maximum HR during workouts). We grouped participants by clinical recovery timing (RTP <28 days vs. ≥28 days post-injury) and compared physical activity measures using independent samples t-tests. We then identified the sensitivity, specificity, and classification accuracy of cutpoints for each exercise variable using a Receiver Operating Characteristic (ROC) and Area under the Curve (AUC) analysis.
Results:
Half (n=13) of the participants required ≥28 days to receive RTP clearance. The two groups were similar in age, proportion of females, and past concussion history (Table 1). Those who required ≥28 days for RTP clearance reported significantly greater symptom severity at the initial examination than the RTP <28 days group, despite similar initial visit timing (Table 1). During the two weeks after the initial visit, the RTP ≥28 days group took fewer steps/day, exercised fewer days/week, and exercised fewer total minutes/week (Table 2). Among the activity/exercise variables examined, the highest classification accuracy between groups consisted of ≥9,100 average steps/day, ≥4 sessions/week, and spending ≥135 total minutes/week exercising (Table 3).
Conclusion:
Higher daily step counts and more frequent/longer exercise sessions were associated with clearance for RTP within 28 days from concussion in adolescent athletes. These preliminary results further support the benefit of physical activity during concussion recovery. However, our study cannot assess the causal effect of these findings, given that those who felt better earlier may have been willing to participate in more physical activity. Further research is needed to develop duration-, frequency- and intensity-specific physical activity level guidelines to aid clinicians in concussion management.
