Accuracy and precision of any measurement is a foundation of scientific knowledge development (Hopkins, 2000), as it investigates how close a measurement is to the true value and whether it can be repeated under several trials. In this instance, the assessment of key whole-body markers such as oxygen uptake, carbon dioxide output, ventilation, respiratory exchange ratio (and subsequent estimation of energy expenditure) are fundamental tenets of studies in sport and exercise science (Atkinson & Nevill, 1998; Hopkins, 2000). Clinicians and researchers often desire to have data on such key whole-body markers, where direct measurement without adverse effects is problematic or impossible and therefore, the true values remain unknown (Bland & Altman, 1986). Instead, indirect methods and equipment are produced, and a new method or equipment must be assessed by comparison with a recognised procedure or equipment rather than with the true measure (Bland & Altman, 1986; Hopkins, 2000). The new piece of equipment must be assessed against an already established piece of equipment and if the new agrees sufficiently with the old; then the old may be substituted or both devices can be used with similar comparability of findings (Bland & Altman, 1986). The rationale for this study is to compare the recorded data using the former ‘enclosed’ mask (Cosmed K4b2) versus the current inspiratory ‘vented’ version (Cosmed K5), that is recommended for the Cosmed K5 via a method comparison (Bland & Altman, 1986).
Seven males and one female University students (mean ± standard deviation (SD), age (years): 23.5 ± 2.390; height (m): 1.775 ± 0.026 and mass (kg): 80.375 ± 10.474) volunteered to participate in the study following approval by the local ethics committee. The study adopted a repeated measures design involving two mask types (vented versus enclosed) assessed at two different types of intensities (RPE10 versus RPE15). Prior to the participants arrival, the Cosmed K5 was calibrated using a standard procedure (Baldari et al., 2015; Palange, Laveneziana, Neder & Ward, 2018) including a turbine (3L syringe), reference gas (16% O2 and 5% CO2) and delay calibration.
The results indicate that the Cosmed-K5 mask was mainly strongly correlated with the Cosmed K4b2 mask but was not significant and was not correlated enough to fit into Bland and Altman’s (1983) 95% ICC. For future research to develop this study further, the requirement of more trials (>3) for each condition (e.g. enclosed mask and vented mask at RPE10 and RPE15 must be trialled at least 3 times each) and the number of participants
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(>50) as suggested by Hopkins (2000) will need to be increased for science to truly understand the reliability and validity of the Cosmed K5 and the mask the Cosmed-K5 comes equipped with. The use of the method comparison (Bland & Altman, 1986) has allowed the study to see that the Cosmed-K5 mask does correlate with the Cosmed K4b2 mask, but not significantly under the 95% ICC (Bland & Altman, 1983; Giavarina, 2015). Although Baldari et al. (2015) found that the Cosmed-K5 showed very high reliability and validity with an ICC ranging from 0.975 to 1 when investigating V̇O2 and V̇CO2. Publication of this data will help science to thoroughly examine the Cosmed-K5 and the mask that it is equipped with, such as been done in recent years (Veluswamy, Guddattu & Maiya, 2015; Baldari et al., 2015; Davidson, Gardinier & Gates, 2016; MacFarlane, 2017).