The Relationships Among Critical Power Determined From a 3-Min All-Out Test, Respiratory Compensation Point, Gas Exchange Threshold, and Ventilatory Threshold

Abstract

These findings suggest CP and RCP demarcate the heavy from severe exercise-intensity domain and result from a different mechanism of fatigue than that of GET and VT, possibly hyperkalemia.

High-intensity interval training and β-hydroxy-β-methylbutyric free acid improves aerobic power and metabolic thresholds

“…Further, the measurement of specific fatigue thresholds during a graded exercise test, like VT and RCP, may be useful for demarcating the heavy or severe exercise intensity domains, respectively [24]. For example, VT has been associated with the minimum exercise intensity that results in excessive CO 2 production from the bicarbonate buffering of hydrogen ions [38,39], while exercise above RCP has been associated with the severe intensity domain which leads to excessive minute ventilation resulting from hyperkalemia [24,40]. The measurement of fatigue thresholds (VT, RCP), therefore, may provide possible mechanistic explanation for aerobic performance changes from training or nutritional interventions.…”

“…Prior to testing, each participant was fitted with a Polar Heart Watch system to record the participants’ heart rate (Polar Electro Inc., Lake Success, NY). Following the procedures described by Bergstrom et al [24], participants were instructed to maintain a pedaling cadence of 70–75 revolutions per minute (RPM) at an initial workload of 75 W. The workload increased 25 W every two minutes until he or she was unable to maintain a cadence above 70 RPM for ~10s despite verbal encouragement, or volitional fatigue. Prior to each graded exercise test, open-circuit spirometry (TrueOne 2400® Metabolic Measurement System, Parvo Medics, Inc., Sandy, UT) was calibrated with room air and gases of known concentration, which was used to estimate V O 2 peak (ml∙kg -1 ∙min -1 ) by sampling and analyzing breath-by-breath expired gases.…”

“…The VT was determined by plotting and determining the point of increase in the V E / V O 2 versus V O 2 curve as the V E / V CO 2 versus V O 2 curve remained constant or decreased [24,26]. The RCP as described by Beaver et al [26] was identified using the V-Slope method by plotting the V E versus V CO 2 .…”

Exercise Intensity Thresholds

“…Previous studies have attempted to examine the association between these indices of intensity by comparing the POs associated with each 'threshold' (5,13,31). The attractiveness of this approach resides in the simplicity of obtaining a PO associated with CP and MLSS while avoiding the necessity of: a) measuring gas exchange during prolonged constant-load exercise (at ) may be interpreted as large changes in exercise intensity (i.e., PO).…”

Caffeine ingestion improves power output decrement during 3-min all-out exercise

“…The improved effort sensation and muscular strength might contribute to the ergogenic effects of caffeine during short-term, high-intensity exercise. Recently, the 3-min all-out test (3MT) has been developed to simultaneously assess CP and W′ in a single trial (Burnley et al 2006;Vanhatalo et al 2007;Cheng et al 2012;Bergstrom et al 2013). Thus, the first objective of the present study was to examine the effect of caffeine ingestion on CP and W′ values in trained athletes after 3MT participation.…”