Gunnar Borg

Psychophysical bases of perceived exertion.

There is a great demand for perceptual effort ratings in order to better understand man at work. Such ratings are important complements to behavioral and physiological measurements of physical performance and work capacity. This is true for both theoretical analysis and application in medicine, human factors, and sports. Perceptual estimates, obtained by psychophysical ratio-scaling methods, are valid when describing general perceptual variation, but category methods are more useful in several applied situations when differences between individuals are described. A presentation is made of ratio-scaling methods, category methods, especially the Borg Scale for ratings of perceived exertion, and a new method that combines the category method with ratio properties. Some of the advantages and disadvantages of the different methods are discussed in both theoretical-psychophysical and psychophysiological frames of reference.

Perceived exertion : A note on 'history' and methods

ABSTRACTEarly studies of subjective force estimates for short-time work on a bicycle ergometer are reviewed. Results showed that perceived pedal resistance followed a positively accelerating function with an exponent of 1.6. A model for inter-individunl comparisons using subjective range as a frame

A category-ratio perceived exertion scale: relationship to blood and muscle lactates and heart rate.

The purpose of this investigation was to study the relationship between perceptual ratings from Borgs new category-ratio scale and some physiological variables during exercise. To accomplish this, scale ratings were related to blood and muscle lactate accumulation and heart rates during a progressive, maximal exercise test on the cycle ergometer. Ten physically active males were utilized as subjects; lactate data were recorded on only 7 of the 10 subjects. Three ratings of perceived exertion were made at each stage of the exercise test: leg effort (LE), cardiorespiratory effort (CE), and leg pain (LP). All ratings showed a positively accelerating increase with exercise intensity as did both blood and muscle lactate, while heart rate increased linearly. The exponents of the power functions describing the perceptual variation ranged from 1.63-1.67 compared to 2.2 for blood lactate and 2.7 for muscle lactate. Polynomial analysis revealed a similar quadratic trend for both perceptual and blood lactate data; however, muscle lactate demonstrated a cubic trend. No significant differences were found between CE and LE at 100, 200, and 300 W (P greater than 0.05). Subjects with the highest percentage of slow-twitch muscle fibers (mean ST%=51.14) rated LE and CE significantly lower ( mean of all power outputs, 0-300 W) than those with the lowest ST% (mean=34.52). It is concluded that the ratings from the category-ratio scale correspond very well with glycogenolytic metabolism leading to lactate accumulation during exercise.

Perceived exertion related to heart rate and blood lactate during arm and leg exercise

SummaryTo compare some psychophysiological responses to arm exercise with those to leg exercise, an experiment was carried out on electronically braked bicycle ergometers, one being adapted for arm exercise. Eight healthy males took part in the experiment with stepwise increases in exercise intensity every 4 min: 40—70—100—150—200 W in cycling and 20—35—50—70—100 W in arm cranking. Towards the end of each 4 min period, ratings of perceived exertion were obtained on the RPE scale and on a new category ratio (CR) scale: heart rate (HR) and blood lactate accumulation (BL) were also measured.The responses obtained were about twice as high or more for arm cranking than for cycling. The biggest difference was found for BL and the smallest for HR and RPE. The incremental functions were similar in both activities, with approximately linear increases in HR and RPE and positively accelerating functions for CR (exponents about 1.9) and BL (exponents 2.5 and 3.3 respectively). When perceived exertion (according to the CR scale) was set as the dependent variable and a simple combination of HR and BL was used as the independent variable, a linear relationship was obtained for both kinds of exercise, as has previously been found in cycling, running, and walking. The results thus give support for the following generalization: For exercise of a steady state type with increasing loads the incremental curve for perceived exertion can be predicted from a simple combination of HR and BL.

The increase of perceived exertion, aches and pain in the legs, heart rate and blood lactate during exercise on a bicycle ergometer

SummaryThis study was designed to show the general increase in perceived exertion, perception of aches or pain in the legs, heart rate (HR), and blood lactate, and the covariance between these variables during bicycle ergometer work, and to describe individual differences both within and between power levels by testing a large group (28 male students).Estimates of perceived exertion and feelings of aches or pain in the legs were recorded using Borgs category-ratio scale (CR-10). The subjects were tested with a stepwise increase of power levels with 40 W increments up to a voluntary maximum.Though HR increases fairly linearly with power, the other variables follow positively accelerating functions with exponents of about 1.6–2 for the perceptual variables, and an exponent of about 3 for blood lactate.The results from the 8 most fit subjects could be described in the same way as for the whole group except for blood lactate, where there was a need to include a threshold value (b), that, together with a rest value (a), shows the starting point of the function (R=a+c(W−W0)n).The data support the idea that a combination of heart rate and blood lactate is a better predictor of perceived exertion and feelings of aches and pain in the legs, than is each of the single physiological variables taken alone.

Individual differences in perceived exertion assessed by two new methods.

Each of 30 male subjects judged, in a single session, the loudness of a 1000-Hz tone and the exertion perceived while pedaling a bicycle. Two psychophysical methods were used—one employing a combined category-ratio scale whose upper limit was defined as “maximum sensation” and the other a freer magnitude-estimation scale having no verbal labels. Both methods yielded data consistent with power functions, although the combined category-ratio scale gave slightly smaller exponents. The category-ratio estimates provided a measure of individual differences in perceived exertion: At any work level, the differences across subjects in judgment correlated with differences in heart rate (a physiological indicant of strain); this result is consistent with Borg’s hypothesis that in dynamic work, maximal sensation is at least roughly equivalent across subjects. When the magnitude and the category-ratio estimates were converted to equivalent loudness (Stevens and Marks’s method of magnitude matching), the derived loudness values also correlated with heart rate: This outcome provides evidence for the utility of the cross-modal procedure and provides further evidence consistent with Borg’s model of perceived exertion.

Subjective Aspects of Physical and Mental Load

Abstract Methods of measuring subjective difficulty, effort and other aspects of work-load which have been developed by the author and his colleagues are described, and the use of these methods as means of distinguishing between individuals, and their relationships to psychometric measures, are discussed. Applications are noted to both physical and mental work.

Twelve meanings of the measure constant in psychophysical power functions

The measure constant in the psychophysical power equation can have at least 12 distinct referents. These depend upon standardized (SI) units of measurement of the physical stimulus, psychophysical method, group and individual differences in judgment, modality- or quality-specific differences, special sensory/perceptual characteristics, characteristics of central/peripheral processing, pathological differences in sensory/perceptual reaction, and differences in the transformation of distal to proximal stimuli.

Psychophysics in action

Introductory Philosophical Considerations.- Borgs Postulate and the Philosophy of Mind.- Theoretical and Experimental Aspects.- Data-Equivalent Models in Psychophysics: Examples and Reflections.- What Happens When We Compare Two Stimuli?.- Human Self-Assessment Process Theory: An Eight-Factor Model of Human Performance and Learning and Everymans Causation.- For Hedgehogs and Foxes: Individual Differences in the Perception of Cross-Modal Similarity.- Deceptive Psychophysics: The Probe-Signal Method and Focused Attention.- Static and Dynamic Exertion: A Psychophysical Similarity and Dissimilarity.- The Study of Individuals in Psychophysical Measurement.- Physiological and Clinical Aspects.- Rating of Perceived Exertion in Children and Adolescents: Clinical Aspects.- Comparison of Rated Perceived Exertion and Constant Effort During Cycling Exercise.- Rating of Perception of Symptoms as an Aid in Medical Diagnostic Exercise Testing.- Differential Effect of Blood Lactic Acid and pH on Peripheral Exertional Perceptions.- Author Index.

Changes in physical performance induced by amphetamine and amobarbital

The effect of amphetamine sulphate and amobarbital on maximal physical performance was examined.Each subject underwent on two different occasions a test on a bicycle ergometer, consisting of a series of short intermittent exercises of maximal character, the CSET (Cycling Strength and Endurance Test).The 34 male subjects tested were divided into three groups (A, B, and C) on the basis of their results of the first test. Before the second test started, group A was given amphetamine sulphate, group B amobarbital and group C placebo. The final performances in the CSET improved under the influence of amphetamine, but the initial ones did not. After treatment with amobarbital the performance decreased. These results may be interpreted as effects on processes which are similar to those influenced by reduced performance demands, and which are related to work motivation.