Abstract
Many individuals with spinal cord injury (SCI) have altered physiological responses to physical activity (PA), which can influence the perceived intensity and accuracy of self-reported PA. We examined correlations between physiological (oxygen uptake (V̇O2) measured by portable metabolic system) and self-reported (PA Recall Assessment for People with SCI (PARA-SCI)) measures of time engaged in PA of different intensities in individuals with SCI. Nine adults with SCI (49±13 years, 6M/3F) completed a graded exercise test to exhaustion to determine peak aerobic capacity (V̇O2peak). Individualised cut-points were established whereby mild, moderate, and vigorous intensity PA were designated as 20-39, 40-59, and 60+% of V̇O2reserve, respectively. On a separate day, participants wore a portable metabolic system that recorded breath-by-breath V̇O2. They subsequently completed the PARA-SCI with a recall period covering the day of portable metabolic monitoring. Participants wore the portable metabolic system for 301±22 minutes. Applying individualised PA intensity cut-points, participants completed 65±44, 20±13, 4±9 minutes of mild, moderate, and vigorous PA, respectively. Time engaged in moderate-to-vigorous PA recorded by portable metabolic monitoring and the PARA-SCI shared a significant correlation (r=0.659, p=0.027). There was no association between other metabolic monitoring outcomes and equivalent PARA-SCI outcomes. These findings highlight challenges in differentiating moderate and vigorous intensity PA among people with SCI. This may be due to the way recall measures describe sensations associated with PA intensity domains and/or device limitations. Whether this is due to a SCI-specific psychophysiological disconnect between physiological effort of PA and the perception of effort remains unclear.
