Intensity of physical activity as a percentage of peak oxygen uptake, heart rate and Borg RPE in motor-complete para- and tetraplegia

OBJECTIVE: The aims were to describe VO(2peak), explore the potential influence of anthropometrics, demographics and level of physical activity within each cohort; b) to define common, standardized activities as percentages of VO(2peak) and categorize these as light, moderate and vigorous intensity levels according to present classification systems, and c) to explore how clinically accessible methods such as heart-rate monitoring and Borg rating of perceived exertion (RPE) correlate or can describe light, moderate and vigorous intensity levels. DESIGN: Cross sectional. SETTING: Rehabilitation facility and laboratory environment. SUBJECTS: Sixty-three individuals, thirty-seven (10 women) with motor-complete paraplegia (MCP), T7-T12, and twenty-six (7 women) with motor-complete tetraplegia (MCT), C5-C8. INTERVENTIONS: VO(2peak) was obtained during a graded peak test until exhaustion, and oxygen uptake during eleven different activities was assessed and categorized using indirect calorimetry. MAIN OUTCOME MEASURES: VO(2peak), Absolute and relative oxygen consumption, Borg RPE. RESULTS: Absolute VO(2peak) was significantly higher in men than in women for both groups, with fairly small differences in relative VO(2peak). For MCP sex, weight and time spent in vigorous-intensity activity explained 63% of VO(2peak) variance. For MCT sex and time in vigorous-intensity activity explained 55% of the variance. Moderate intensity corresponds to 61–72% HR(peak) and RPE 10–13 for MCP vs. 71–79% HR(peak), RPE 13–14 for MCT. CONCLUSION: Using current classification systems, eleven commonly performed activities were categorized in relative intensity terms, (light, moderate and vigorous) based on percent of VO(2peak), HR(peak) and Borg RPE. This categorization enables clinicians to better guide persons with SCI to meet required physical activity levels.