Exercise tolerance during VO_2maxtesting is a multifactorial psychobiological phenomenon

Abstract

Fifty-nine men completed a VO test and a questionnaire to establish reasons for test termination, perceived exercise reserve (difference between actual test duration and the duration the individual perceived could have been achieved if continued until physical limitation), and perception of verbal encouragement. Participants gave between 1 and 11 factors as reasons for test termination, including leg fatigue, various perceptions of physical discomfort, safety concerns, and achievement of spontaneously set goals. The two most common main reasons were leg fatigue and breathing discomfort, which were predicted by pre-to-post test changes in pulmonary function (p = 0.038) and explosive leg strength (p = 0.042; R = 0.40). Median (interquartile range) perceived exercise reserve, was 45 (50) s. Two-thirds of participants viewed verbal encouragement positively, whereas one-third had a neutral or negative perception. This study highlights the complexity of exercise tolerance during VO testing and more research should explore these novel findings.

A call to action towards an evidence‐based approach to using verbal encouragement during maximal exercise testing

“…Increases in VO 2 max test duration with verbal encouragement also have been found to translate into improvements in important physiological measures, such as VO 2 max and maximal heart rate (Andreacci et al ., ; Chitwood et al ., ; Moffatt et al ., ). These improvements are consistent with the observation that most participants perceive verbal encouragement as helpful in motivating them to invest effort during maximal exercise testing (Midgley et al ., in press). Performance improvements have not been a consistent finding; however, as verbal encouragement tended to improve performance only in the longer duration tests.…”

“…What constitutes effective verbal encouragement with respect to what is said is currently unknown; however, a recent study provides some insight into this issue (Midgley et al ., in press). Participants were asked if there were any particular verbal encouragement phrases they found useful for motivating them to invest effort during a VO 2 max test.…”

“…() for plantar flexion maximal voluntary contraction force, where verbal encouragement significantly improved performance in a low conscientiousness group, but not in a high conscientiousness group. Further insight into this issue comes from recent findings that around one‐third of participants reported either a neutral or negative perception of verbal encouragement during VO 2 max testing (Midgley et al ., in press). Of particular note is that the participants with a negative perception reported that encouragement was annoying or distracting.…”

“…() observed that verbal encouragement was effective in increasing treadmill run time during VO 2 max testing when it was delivered every 20 s throughout the test, but not when delivered every 60 or 180 s. The timing of verbal encouragement also has been found to be important. In a study investigating participants’ perceptions of verbal encouragement during VO 2 max testing, some participants perceived the encouragement as equally useful throughout the test (Midgley et al ., in press). More often, however, participants stated the encouragement was only useful or more useful later in the test when they were feeling tired and thinking about terminating the test.…”

“…() reported that increasing the loudness of encouragement from 66 to 88 dB during isometric contractions of the triceps brachii muscle increased force by 8%; however, no studies have investigated variations in loudness of verbal encouragement during ‘whole body’ maximal exercise testing. Of note, two participants in a recent study stated that the tone of voice during verbal encouragement was most important (Midgley et al ., in press). Lastly, simultaneous hand clapping has been used with verbal encouragement during maximal exercise testing (Andreacci et al ., ); however, the efficacy of this strategy compared to verbal encouragement alone has not been established.…”