ROBERTSON, R. J., F. L. GOSS, N. F. BOER, J. A. PEOPLES, A. J. FOREMAN, I. M. DABAYEBEH, N. B. MILLICH, G. BALASEKARAN, S. E. RIECHMAN, J. D. GALLAGHER, and T. THOMPKINS. Children’s OMNI Scale of Perceived Exertion: mixed gender and race validation. Med. Sci. Sports Exerc., Vol. 32, No. 3, pp. 452–458, 2000.
Purpose: The newly developed Children’s OMNI Scale of Perceived Exertion (category range: 0 to 10) was validated using separate cohorts of female and male, African American and white subjects. Each of the four cohorts contained 20 clinically normal, nonobese children, 8–12 yr of age.
Methods: A cross-sectional, perceptual estimation paradigm using a single multi-stage cycle ergometer test protocol was used. Oxygen uptake (V̇O2; mL·min−1), heart rate (HR; beats·min−1) and ratings of perceived exertion for the overall body (RPE-Overall), legs (RPE-Legs), and chest (RPE-Chest) were determined at the end of each continuously administered 3-min power output (PO) (i.e., 25, 50, 75, and 100 W) test stage.
Results: The range of responses over the four POs for all cohorts was V̇O2: 290.8 to 1204.0 mL·min−1; HR: 89.2 to 164.4 beats·min−1; and RPE-Overall, RPE-Legs, and RPE-Chest: 0.85 to 9.1. First-order correlation and linear regression analyses were performed for each cohort separately and the total sample using a repeated measures paradigm over the four POs. For all correlation/regression paradigms RPE-Overall, RPE-Legs, and RPE-Chest distributed as a positive linear function of both V̇O2 and HR; r = 0.85 to 0.94;P < 0.01. Differences between RPE-Overall, RPE-Legs, and RPE-Chest were examined with ANOVA for the repeated measures paradigm. RPE-Legs was higher (P < 0.01) than RPE-Chest and RPE-Overall at 25, 50, 75, and 100 W. RPE-Chest did not differ from RPE-Overall at 25 and 50 W but was lower (P < 0.01) than RPE-Overall at 75 and 100 W.
Conclusion: The psycho-physiological responses provide validity evidence for use of the Children’s OMNI Scale over a wide range of dynamic exercise intensities.
This investigation examined response validity of the newly developed Children’s OMNI Scale of Perceived Exertion (i.e., OMNI Scale) (Fig. 1) using African American and white female and male cohorts. The OMNI Scale was developed because of growing clinical and experimental interest in measuring perceptions of physical exertion in children and adolescents (1,9,11,13–15,19,20). Many of these pediatric investigations used category rating scales developed for use with adults. Such adult formatted perceived exertion scales can pose methodological and semantic limitations when applied to children and adolescents (19). Williams et al. (21) observed that some pediatric subjects—particularly those younger than 11 yr old—cannot consistently assign numbers to words or phrases that describe exercise-related feelings. Many younger children also have difficulty interpreting certain verbal scale descriptors that are not semantically consonant with their present vocabulary.
In response to the forgoing limitations of adult formatted perceived exertion scales, Williams et al. (21) developed the Children’s Effort Rating Table (CERT). Initial experiments provided evidence supporting the validity of the CERT for use with young children. However, more recent work involving the CERT demonstrated nonlinearity of perceptual-physiological responses, indicating diminished scale sensitivity over the upper heart rate range during dynamic exercise (12).
The present investigation recognizes the potential methodological and semantic limitations of existing category perceived exertion scales when used with children. As such, an estimation paradigm was used to examine the validity of a newly developed perceived exertion scale for use with children, i.e., the Children’s OMNI Scale. The OMNI Scale has a developmentally indexed category format that contains both pictorial and verbal descriptors positioned along a comparatively narrow numerical response range of 0 to 10. The “exertional meaning” of each pictorial descriptor is consonant with its corresponding verbal descriptor. In this way, the range of numerical category responses that comprises the OMNI scale is defined by both pictorial and verbal descriptors. Of practical importance in developing this scale was the expectation that a single format could be used with female and male children from multi-racial origins; hence the name OMNI Scale.
The OMNI Scale format was developed according to a four part sequential paradigm using a mixed gender/race sample of children as follows:
(a) Four pictorial descriptors illustrating a child experiencing various levels of exertion while pedaling a bicycle up a hill were produced by a graphic artist. Bicycling was chosen because it is a form of physical activity common among African American and white female and male children of varying ages.
(b) African American and white, female and male children were shown the four-part pictorial set and asked to verbally describe the intensity of physical exertion depicted by each illustration. Individual words and whole phrases were accepted as responses. Verbal responses were included in the primary descriptor pool if they met one of the following criteria: (i) described effort or exertion, (ii) pertained to intensity of the exercise/work, and (iii) described either somatic signs or symptoms of exertional comfort/discomfort.
(c) Semantic differential analysis (16) was used to select from the primary pool six verbal descriptors, each having discrete exertional intensity properties. A total of 1582 verbal expressions containing various word combinations that described the level of exertion depicted in the four pictorial illustrations of the youth cyclist were obtained from 206 African American and white females and males, aged 8–12 yr. The trunk word for the OMNI Scale, TIRED, appeared 475 times in this primary verbal descriptor pool. It is of note that the words light and hard are the two principal trunk words for the Borg Scale. While the word hard was used 89 times the word light was not used (0 responses) by the children studied. The analysis identified verbal descriptors that share a common meaning among and are generalizable to children that have the same characteristics as the subject cohorts used in the present experiment.
(d) The OMNI Scale was then formatted by selecting six semantically discrete verbal descriptors of exertion. These descriptors distributed in equal intensity intervals along a response continuum ranging from minimal to maximal exertion. The six pictorial descriptors were then positioned in equal perceptual increments along the 0–10 response range. The four pictorial descriptors were similarly positioned along the numerical response range. This formatting procedure resulted in four of the verbal descriptors being placed in juxtaposition to the four pictorial descriptors, establishing a verbal-visual correspondence in exertional properties. The semantically consonant pictorial and verbal descriptors were then positioned along a visually discernible hill in ascending order of perceived intensity of exertion.
The present investigation recognized potential interracial differences in both the use and interpretation of words and phrases that describe physical exertion. As such, OMNI Scale responsiveness was examined separately for cohorts of African American and white children. Evidence of scale validity was accepted according to the following expectations: (a) RPE derived from the OMNI Scale would distribute as a positive linear function of submaximal exercise intensity for separate and combined cohorts of African American and white, female and male children, and (b) the OMNI Scale could be used by children to differentially rate the intensity of exertional signals from the legs and chest during dynamic exercise.