Author(s): SCHAFFARCZYK, M., SIEMERS, P., GRONWALD, T., Institution: MEDICAL SCHOOL HAMBURG, Country: GERMANY, Abstract-ID: 2412

INTRODUCTION:
The purpose of this study was to compare anaerobic threshold (AnT) concepts like the second ventilatory threshold (VT2) with less utilized ones like the reverse lactate test (RLT) and the calculated maximal lactate steady-state (MLSSc) as correlates for the experimentally determined MLSS, though with just one testing session needed, in cycling.
METHODS:
15 triathletes and cyclists performed an isokinetic sprint of 15s to determine maximal glycolytic rate (VLaMAX) followed by an incremental test with continuous assessment of gas exchange to determine maximal oxygen uptake (VO2MAX) and VT2. MLSSc was calculated using VO2MAX and VLaMAX. RLT was conducted on a separate day and consisted of three to four priming stages, followed by one stage at estimated 105% of MLSS and reverse segments, accompanied by blood lactate samples taken every stage. The wattage corresponding to the apex of the reverse lactate plot corresponds to the RTL’s AnT estimate. Power at experimental (VT2, RLT) and calculated (MLSSc) AnTs were compared using statistical methods for assessing agreement.
RESULTS:
Cycling power for VT2, RLT and MLSSc was assessed at 250±36W, 236±34W, 229±38W. Correlations were high (RLT vs. MLSSc: ICC3,1 = 0.806; VT2 vs. RLT: ICC3,1 = 0.890) and moderate (VT2 vs. MLSSc: ICC3,1 = 0.699). However, there were significant differences between VT2 and MLSSc (p = 0.012) and VT2 and RLT (p = 0.009), but not for RLT and MLSSc (p = 0.268). RLT vs. MLSSc also showed the smallest mean difference (7.1±22.4W), though with wide limits of agreement (LoA: 50.9 to -36.7W). For VT2 vs. MLSSc, and VT2 vs. RLT mean difference was 21.3±28.7W (LoA: 77.6 to -35.1W) and 14.1±16.5W (LoA: 46.5 to -18.2W).
CONCLUSION:
The results accord to published comparisons of AnT concepts, also showing large individual differences. The observed deviations could originate from the methodological procedure, but are most likely attributable to divergent underlying physiological mechanisms with each concept representing a different entity. The MLSSc includes more information about the interaction of endurance performance determinants (VO2MAX, VLaMAX) and could give more goal-oriented training recommendations with minimal additional effort in just one testing session. The next step should involve the validation of the calculation with actual determined MLSS. However, decision for a concept depends on practicability, knowledge background, and experience in ecological valid application settings.