Civil Engineering Reference
In-Depth Information
TABLE 37.1 Borg's 15-Point Scale
for
Ratings of Perceived Exertion
6
7
Very, very light
8
9
Very light
10
11
Fairly light
12
13
Somewhat hard
14
15
Hard
16
17
Very hard
18
19
Very, very hard
20
Source: Adapted from Borg, G.A. (1982). Med
Sci Sports Exerc, 14, 377-381. With permission.
The RPE scale was developed according to the principles of quantitative semantics, which deals with the
meaning of words and the quantitative relationship between verbal expressions (Noble and
Robertson, 1996; Borg and Borg, 2002). Borg chose verbal expressions for the scale that were not only
well defined but also had a comparatively equal meaning for subjects. The original RPE scale was developed
to be linearly related to heart rate, and based on subjective force estimates provided by subjects while per-
forming short-time work on a bicycle ergometer with a stepwise increase in workload. In order to relate the
scale linearly with heart rate, the scale number were arranged to conform to the absolute heart rate quan-
tities. Since heart rate ranges from 60 to 200 in a healthy group of adults, the scale numbers were set from 6
to 20 (Table 37.1). Close relationship with the pulse rate and application of quantitative semantics support
the notion that the RPE scale is a category scale with interval properties, that is, the scale not only rank
sensations but, also satisfies the equal interval criterion (Noble and Robertson, 1996).
Since the original 15-point RPE scale does not reflect the more exponential growth of perceptual
responses as intensity increases, Borg (1982) developed a Category-Ratio (CR10) scale for perceived
exertion (Table 37.2). This scale follows the growth of perceptual responses, and the exponential
growth of nonlinear physiological responses such as lactate accumulation and pulmonary ventilation.
This scale also combined advantages of both scales, that is, category-rating and ratio scale (Borg,
2002). CR scale can be useful for identifying local sensations of effort during high-intensity exercise.
However, a valid determination of direct intensity levels with this scale is not possible. Thus, Borg
(1982) did not recommend use of this scale in place of the 15-point RPE scale for general exercise
testing. The CR10 scale has 12 categories, with values ranging from 0 to 10, with “0” for “nothing at
all” and 0.5 for “extremely weak (just noticeable)”. In order to prevent a ceiling affect, the term
“maximal” was placed outside of the scale, to which any number can be assigned by subject (Noble
and Robertson, 1996; Borg and Borg, 2002).
The original Borg RPE scale has been shown to be an accurate and reliable instrument to measure per-
ceived exertion in a number of investigations. The use of the Borg scale was validated on several tasks
such as bicycle ergometer, walking, stool stepping, and walking treadmill. Various physiological measures
of physical exertion: heart rate, blood and muscle lactate concentration, oxygen uptake, ventilation and
respiration rate have been used as criterion in the validation research (Noble and Robertson, 1996;
Russell, 1997; Chen et al., 2002). The validation against heart rate showed correlation coefficients in
the range of r
0.80-0.90 (Noble and Robertson, 1996; Hampson et al., 2001; Chen, 2002). The
reliability coefficients established by test-retest method were 0.78 and 0.90 for bicycle ergometer tasks
(Skinner et al., 1973; Noble and Robertson, 1996), 0.76 for the oscillating test, 0.76 for stool stepping
exercise, and 0.76 for treadmill walking test (Noble and Robertson, 1996). In addition, validation
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