One reason for the good reproducibility on the group level for model 1, despite only making use of three submaximumimal work rates, can be the span of the HR attained between work rate 1 and 3 (in average 98–137 and 98–150 for males and females, respectively). It is equally important that the utilized ranges of HR from cycle commuting (in average 113–149 and 118–154 for males and females, respectively) are within, or only slightly above, the range of the HR from the work rates in the laboratory (cf. Tables 3 and 5). If instead VO2 would be estimated from higher or lower HR than those established in the laboratory, it is possible that greater test-retest differences would be seen (cf. Fig 1).
Ultimately, the newest methods of twenty four-hours Hours by Christensen et al
A xpress hledat comment on the field heart rates used is that almost half the cyclists were tested in the laboratory at a different time of day compared to their cycle commuting tests. However, McCrory et al. found that within-day variations were not significantly different at the higher activity levels in their study, i.e. normal to fast walking. Thus our population probably had levels of intensity that were high enough to eliminate circadian influences. Another comment favoring a stability in the measurement conditions is that the mean values for the positions of % HRmax used to establish the HR-VO2 relations related well to the expected VO2 relative to VO2max in both sexes .
, and considerably more favourable in relation to using the HR-VO2 method than those indicated by Christensen et al. . There are several explanations for that. The measurements used by Christensen et al. for establishing HR-VO2 regression equations were resting and sitting, as well as three low to intermediate exercise rates on an ergometer cycle (8–100 watt) and three exercise rates on a treadmill, thus altogether eight measurement points. For both the slope and the y-intercept of the regression equations, the measurements at low levels of HR are, under those circumstances, more influential. At the same time it is well known that the HR-VO2 ratios at rest and sitting are quite unstable, resulting in variations in regression equations [11, 25, 41]. 2 and HR will be higher after a certain HR level, which has been termed “flex HR” [12, 42, 43], which could be another reason for the results of Christensen et al. . Furthermore, they mixed the work forms of cycle ergometer and treadmill as bases for the HR-VO2 measures, which is in itself problematic, since the HR response for a given VO2 can differ in these different forms of movement . This creates a greater risk for non-stability in regression equations with repeated measurements. resulted in a mean value of 86 beats per minute. In line with the reasoning in the Introduction (cf. Fig 1) a heart rate close to the endpoint of the spectrum of measurement points forming the regression equation will most probably lead to lower reproducibility. Another potential explanation for their results relates to their use of a heterogeneous sample of predominantly patients and large variations in age, whereas we studied a sample of healthy and physically active middle aged individuals.
With reported that, one should keep in mind that this new exterior legitimacy of our conclusions when considering other sorts of users is actually undecided. Hence, so you’re able to send the general education throughout these respects, there can be indeed a need for further studies of them things.
In addition, we do not know any thing regarding external legitimacy of your own Time method on the laboratory when it comes to occupation requirements such since during stage commuting. Three research has checked the latest intensity of cycle travelling having fun with some other Time steps from inside the samples of non-typical stage commuters [45, 46, 47]. Although not, not one of those training believed that, for causes such as aerobic drift which have extended functions periods [12, 48, 49] otherwise worry due to guests requirements [50, 51], the relationship measured regarding laboratory can vary when being in a pattern driving ecosystem, hence consequently the fresh shown intensity of years driving will be completely wrong. It is the focus within subsequent training.