摘要Outpatients with an acquired brain injury(ABI)experience physical,mental,and social deficits.ABI can be classified into two subgroups based on mechanism of injury:mild traumatic brain injury(mTBI;e.g.,concussion)and other ABI(e.g.,stroke,brain aneurysm,encephalitis).Our understanding of habitual activity levels within ABI populations is limited because they are often collected using self-report measures.The purpose of this study was to,1)describe the habitual activity levels of outpatients with ABI using objective and self-report monitoring,and 2)compare the activity levels of outpatients with mTBI vs.other ABI.Sixteen outpatients with other ABI(mean?standard deviation:[58?13]years,9 females)and 12 outpatients with mTBI([48?11]years,9 females)wore a thigh-worn activPAL 24 h/day(h/day)for 7-days.Outpatients with ABI averaged(6.0?2.3)h/day of upright time,(10.6?2.2)h/day of sedentary time,(5.6?2.7)h/day in prolonged sedentary bouts>1 h,(5960?3037)steps/day,and(11?13)minutes/day(min/day)of moderate-vigorous physical activity(MVPA).There were no differences between activPAL-derived upright,sedentary,prolonged sedentary time,and physical activity between the mTBI and other ABI groups(all,p>0.31).Outpatients with ABI overestimated their MVPA levels(t138 min/week)and underestimated sedentary time(?4.3 h/day)compared to self-report(all,p<0.001).Despite self-reporting high activity levels,outpatients with ABI objectively exhibit highly inactive and sedentary lifestyles.The habitual movement behaviours of our sample did not differ by mechanism of injury(i.e.,mTBI versus other ABI).Targeting reductions in objectively measured sedentary time are needed to progressively improve the habitual movement behaviours of outpatients with ABI.