运动中“谈话测试”介绍

jacky

The “Talk Test”
Phil Block, M.S. and Len Kraviz, Ph.D.

Study Reviewed:
Persinger, R., Foster, C., Gibson, M., Fater, D.C.W., & Porcari, J.P. (2004). Consistency of the talk test for exercise prescription. Medicine & Science Sports & Exercise. 36 (9), 1632-1636.

Introduction
Aerobic exercise is a decisively important component of any fitness program. However, establishing and maintaining ideal workout intensities for the most effective and safe workouts can prove to be a challenge for both exercisers and fitness professionals alike. In designing the cardiorespiratory exercise prescription, it is meaningful to consider that many people engage in aerobic exercise to control weight, improve their health status or reduce their disease risk. Knowing your client’s goals and purposes for doing aerobic exercise helps to best determine the intensity, frequency, duration and progression of the exercise prescription.

Traditionally, aerobic exercise programs have been developed around accepted standards of percentages of maximum heart rate and oxygen consumption (VO2). For instance, the American College of Sports Medicine (ACSM) recommends between 55-90% of maximum heart rate or 40-85% of maximum oxygen uptake for most individuals (ACSM 1998). Although the success of these techniques has been consistently demonstrated, many fitness enthusiasts find the necessary objective monitoring, such as continuously checking heart rates, to be difficult and sometimes tedious.

Recent studies have helped validate an easier way to stay on track – the Talk Test. This method appears to be a simple way of maintaining recommended exercise intensities, while avoiding the problems of the more involved practices of heart rate and VO2 assessment (Persinger et al., 2004).

How the Talk Test Works
The Talk Test was developed to be an informal, subjective method of estimating appropriate cardiorespiratory exercise intensity. The method entails maintaining an intensity of exercise at which conversation is comfortable. When an exerciser reaches an intensity at which he or she can “just barely respond in conversation,” the intensity is considered to be safe and appropriate for cardiorespiratory endurance improvement. The newest research supports the usefulness of the Talk Test and highlights its ability to closely reflect actual heart rate and VO2 levels (Persinger et al., 2004).

The Purpose of the Study
This study examined the consistency and effectiveness of the Talk Test as a tool for exercise prescription on the treadmill and cycle ergometer, hypothesizing that the ability to vocalize correlates positively with aerobic exercise intensity on both of these modes of exercise. Thus the researchers were specifically interested in the consistency of the Talk Test for intensity monitoring on a treadmill and cycle ergometer.
The Subjects
Ten male and six female participants (average age = 24 yrs) volunteered to participate in this study. All subjects were considered to be healthy and moderately active. Participants were pre-screened for contraindications to exercise testing prior to the study.
The Testing
All participants performed four separate exercise tests, completing two assessments on a treadmill and two on an electronically braked cycle ergometer. These tests were performed on different days, at the same hour each day. The order of testing was randomized.
The exercise protocol was designed to best meet each participant’s individual exercise capacity. To accomplish this, the treadmill speed was set at a pace that the subjects subjectively felt they could comfortably exercise “virtually indefinitely”, which was either walking or jogging. Intensity was then increased with grade (incline) increments every 2 minutes. The initial cycle ergometer power output was 25 watts, increasing by 25 watts in two-minute stages. Participants who weighed less than 60 kg had a starting power output of 20 watts, increasing by 20 watts in two-minute stages.

One cycle ergometer and one treadmill test was performed to exhaustion by each participant. During these tests, respiratory data was collected using open circuit spirometry and heart rate was monitored throughout the test using radio telemetry (a heart rate monitor). The other two tests involved a Talk Test, with each subject reciting the “Pledge of Allegiance” during the last 30 seconds of each two-minute exercise stage. After recitation, the participants were asked if they could “speak comfortably.” The subjects were permitted to answer, “yes” or “no.” However, if they responded in an uncertain manner, they were considered to be “equivocal” (meaning unclear or questionable), and not able to comfortably speak. When the answer was “no,” the exercise test was terminated. Actual measurements of VO2, ventilatory threshold, and heart rate were compared to the responses made during the Talk Test. See Side Bar 1 for a brief discussion of ventilatory and lactate threshold.

What They Found
The results of this study are extremely interesting. There was a close correlation between the Talk Test, VO2, ventilatory threshold, and heart rate on both the cycle ergometer and the treadmill. This denotes the usefulness of the Talk Test as a simple way of determining appropriate exercise intensity on both of these modes. It appears that by just using the talk test, one can achieve the proper intensity of exercise without having to rely on more invasive or difficult procedures. When comfortable speech is just barely possible (the last stage of exercise where the researchers received a “yes” answer or the “equivocal” stage), the exercise intensity was within the suggested guidelines for exercise prescription based on their VO2 and heart rate data. However, when comfortable speech was no longer possible, the exercise intensity was greater than what is normally recommended for exercise intensity and above the ventilatory threshold. Therefore, ventilatory threshold was highly correlated with the last positive and equivocal stages of the Talk Test.

The Bottom Line
The most practical application of this research is for establishing and maintaining ideal exercise intensities without the demand of expensive laboratory equipment or confusion with pulse check counting. It allows the exerciser and his or her trainer to make use of a subjective intensity assessment permitting a quick, easy and accurate evaluation of exercise intensity. Although no specific guidelines the Talk Test yet exist, we recommend using it in a manner similar to heart rate monitoring, at least once every 15 minutes of aerobic exercise. During group exercise conditions, the Talk Test may be particularly useful. The instructor can readily have students subjectively monitor their exercise intensity by having them cite the “Pledge of Allegiance”. For international students from different cultures, we recommend exercisers cite a popular ‘nursery rhyme’ they are familiar with, as it has been our experience that most cultures have nursery rhymes that exercisers readily know. Remember, if the aerobic participants are able to “talk the talk while walking the walk” (with a little challenge or difficulty), it is likely that the appropriate exercise intensity is being achieved.

Side Bar 1: Ventilatory vs. Lactate Threshold
Exercise physiologists have long used ventilatory and lactate thresholds as laboratory indicators of exercise performance and intensity. Ventilatory threshold describes a non-linear increase in respiration that corresponds with higher levels of exercise intensity. Until ventilatory threshold is achieved, respiration increases fairly linearly with intensity. However, as soon as ventilation breaks from this progressive linear increase, ventilation threshold has been established. Contrariwise, lactate threshold refers to a point during exercise of increasing intensity at which blood lactate begins to accumulate above resting levels. This occurs when the body’s ability to clear lactate is surpassed by its accumulation. When the ventilatory and lactate thresholds are surpassed, exercise performance quickly slows downs, so there is a great interest in training strategies to delay the onset of the lactate and ventilatory thresholds. Although many fitness professionals think of these thresholds as being synonymous, they are in fact very different and can occur at substantially different exercise intensities in the same individual. The most recent research supports the use of the lactate threshold as the best predictor of endurance performance (Dalleck and Kravitz, 2003).

Additional References:
American College of Sports Medicine. (1998). The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness, and Flexibility in Healthy Adults. Medicine & Science in Sports & Exercise. 30(6), 975-991.

Dalleck, L.C. & Kravitz, L. (2003). Optimize endurance training. IDEA Personal Trainer, 14(1) 36-42.


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