Predictors of Physical Activity One Year After Moderate to Severe Traumatic Brain Injury

To identify predictors of moderate to vigorous physical activity (MVPA) at 12-months post-moderate-severe traumatic brain injury (TBI).

Four inpatient rehabilitation centers.

Individuals enrolled in the TBI Model Systems with moderate to severe TBI, admitted to inpatient rehabilitation, and able to ambulate without physical assistance from another person.

Prospective longitudinal cohort study. MVPA was measured by having participants wear an ActiGraph GT3X on their wrist for 7 consecutive days.

We used multivariate regression to predict minutes per week of MVPA at 12 months after TBI. Three classes of predictors were entered hierarchically-demographic and clinical variables (age, sex, body mass index, education, TBI severity, neighborhood walkability score, and self-reported preinjury physical activity [PA] level), baseline TBI-related comorbid conditions (eg, measures of sleep, pain, mood, fatigue, and cognition), and intention to exercise and exercise self-efficacy assessed approximately 1 week after discharge from inpatient rehabilitation.

180 participants (ages 17.7-90.3 years) were enrolled, and 102 provided at least 5 days of valid accelerometer data at 12 months. At 12 months, participants recorded an average of 703 (587) minutes per week of MVPA. In univariate and multivariate analyses, age was the only significant predictor of 12-month MVPA ( r = -0.52). A sharp decline in MVPA was observed in the tertile of participants who were over the age of 61.

Older adults with TBI are at elevated risk of being physically inactive. Assuming PA may enhance health after TBI, older adults are a logical target for prevention or early intervention studies. Studies with longer outcomes are needed to understand the trajectory of PA levels after TBI.