Accessible Exterior Surfaces Technical Article

What was measured and why?

Energy Consumption – Measuring the oxygen a person consumes indicates how much energy the body is producing. When the oxygen consumption is measured at rest (i.e., with the person sitting or lying down), the amount of energy the body is using to function (e.g., for making the heart pump, organs function) can be determined. If an individual walks at a steady pace for 3 to 4 minutes, energy consumption will stabilize at a level that is equal to the energy required to negotiate that environment. By subtracting the resting oxygen consumption from the oxygen consumption while walking/wheeling, the amount of energy being used specifically for walking can be determined.

Walking Speed – If adults are asked to walk at their freely chosen speed they automatically select the type of movement and speed that requires the least amount of energy. If an individual is forced to walk either faster or slower than this chosen pace, the amount of energy used will increase. Therefore, f or this study, subjects were allowed to determine their own preferred pace so that energy consumption in its “most efficient” state could be measured.

Heart Rate and Rating of Perceived Exertion – Rating of perceived exertion (RPE) is a research scale used to document the individual’s perception of how difficult it is for his/her body to perform an exercise (i.e., how hard the individual’s lungs are breathing, and heart is pumping). RPE scores have been shown through research to be consistently related to measures of heart rate and amount of exercise, regardless of the type of exercise. In general, the RPE score is equal to the steady state heart rate divided by 10.

Level of Difficulty – Level of difficulty is similar to the rating of perceived exertion in that it attempts to quantify the individual’s subjective perception of the activity. However, it differs from the rating of perceived exertion in that it is not specific to how the heart and lungs are performing. Often, an unstable surface, for example, may be perceived as very difficult because of the unstable footing, even though the individual does not have to exert him/herself. Level of difficulty was recorded to evaluate factors (e.g., ease of slipping, uneven surfaces) that would not necessarily affect the energy consumption but may impact the overall “accessibility” of the surface.