Abstract (eng)
The aim of this thesis was to compare two commercially available metabolic gas analyzers, namely the MetaLyzer 3B (Cortex Biophysik GmbH., Leipzig, Germany) (ML 3B), and the MasterScreen CPX (Viasys Healthcare, Höchberg, Germany) (MS CPX), as well as validate near infrared spectroscopy (NIRS) as a method to determine the anaerobic threshold (AT) and the respiratory compensation point (RCP).
20 healthy recreationally active sport students (m = 14, w = 6) performed two graded exercise tests (GXT) on the treadmill in an alternate order with either the ML 3B or the MS CPX, with the NIRS applied to the gastrocnemius lateralis muscle during the GXT with ML 3B. NIRS derived AT (NdAT) was determined in the oxygenation index (OI = Δ[O2Hb] – Δ[HHb]) and NIRS derived RCP (NdRCP) was determined in the concentration change of deoxyhemoglobin (Δ[HHb]).
Mean maximal running speed was not significantly different between the two GXTs (P = 0.919). Mean V ̇O2peak of ML 3B was measured significantly higher than MS CPX (3,482 ± 904 mL·min-1 versus 3,246 ± 789 mL·min-1, respectively; P < 0.001), but was significantly correlated (r = 0.982; P < 0.05). NdAT is significantly different than AT (P = 0.014) with a CoV of 24.6% and NdRCP is not significantly different than RCP (P = 0.789) with a CoV of 16.6%.
V ̇O2 of ML 3B and MS CPX can be made comparable using an equation that demonstrates a small error of the estimate: V ̇O2 MS CPX = (V ̇O2 ML 3B – 6.009) / 1.077. According to this study NIRS cannot be used to determine AT and RCP validly.