Fig 1.
Test setup with simultaneous operation of two identical K5 units using a flow signal splitter.
Fig 2.
Test protocols for simulated (A, study 1) and biological (B, study 2) testing. To evaluate intra- and inter-unit reliability, study 1 consisted of four metabolic rates produced by a metabolic simulator (MS), conducted four times for breath-by-breath and four times for dynamic mixing chamber mode (left part A). To evaluate inter-unit differences, study 2 consisted of four increasing stages with a consecutive ramp test in 12 male athletes (right part B). The test was conducted twice with both units operating in a randomized order between participants either both in breath-by-breath or both in dynamic mixing chamber mode.
Table 1.
Study 1. Intra- and inter-unit reliability of two structurally identical units of the metabolic analyzer COSMED K5 in breath-by-breath or dynamic mixing chamber mode during metabolic simulation.
Fig 3.
Bland-Altman plots showing differences between two identical K5-units (COSMED, Rome, Italy).
Both units operated simultaneously either in breath-by-breath (BBB, left part A) or dynamic mixing chamber (DMC, right part B) mode. Y-axis is 100×(K5A−K5B)÷(K5A+K5B/2). The corresponding mean of both units is shown on the X-axis. Solid and broken lines indicate mean difference and 95% limits of agreement or, in case of magnitude dependent differences, linear regression analysis and 95% prediction intervals, respectively. = minute ventilation (BTPS),
= carbon dioxide production (STPD),
= oxygen uptake (STPD), RER = respiratory exchange ratio (STPD).
Table 2.
Study 2. Inter-unit differences of two simultaneously operating COSMED K5s in breath-by-breath and dynamic mixing chamber mode during incremental exercise testing on a cycle ergometer (N = 12).