Training-Induced Changes in the RCP, [HHb]BP and MLSS: Evidence of Equivalence

Purpose:To evaluate whether the coherence in the oxygen uptake (VO2) associated with the respiratory compensation point (RCP), near-infrared spectroscopy derived muscle deoxyhemoglobin ([HHb]) break point ([HHb]BP) and maximal lactate steady state (MLSS) would persist at the mid- and end-point of a seven-month training and racing season. Methods:Eight amateur male cyclists were tested in 3 separate phases over the course of a cycling season (PRE, MID and POST). Testing at each phase included a ramp-incremental test to exhaustion to determine RCP and [HHb]BP. The PRE and POST phases also included constant power output rides to determine MLSS. Results:Compared to PRE, VO2 at both RCP and [HHb]BP was greater at MID (delta: RCP 0.23±0.14 L∙min-1, [HHb]BP 0.33±0.17 L∙min-1) and POST (delta: RCP 0.21±0.12, [HHb]BP 0.30±0.14 L∙min-1)(p<0.05). VO2 at MLSS also increased from PRE to POST (delta: 0.17±12 L∙min-1)(p<0.05). VO2 was not different at RCP, [HHb]BP, and MLSS at PRE (3.74±0.34, 3.64±0.40, 3.78±0.23 L∙...