Background:Caffeine (CAF) Has Been Widely Studied as a Potential Ergogenic that Improves Performance and Alter Physiological and Psychological Responses to Exercise, Based on Likely
Mechanisms: the Inhibition of Adenosine Effects on the Central Nervous System; the Increase in Intracellular Calcium Mobilization; and the Increased Oxidation of Free Fatty Acids. Alternatively,
Placebo when Perceived as Caffeine (PL) may Positively Affect Performance in Physical Tasks, but it is Still Unclear how PL Affects the Ratings of Perceived Exertion (RPE) During Maximum Incremental
Tests (MIT). Therefore, the aim of this Study Was to Determine Whether PL Supplementation (Perceived as Caffeine) may alter RPE and Performance Responses During MIT.
Methods:This Study was a Double-Blind Control Design, which Used Experimental Manipulations with PL and CAF Ingestion (6 Mg.Kg-1 Body Weight) 1-H before the MIT, in a Randomized
Order. Nine Physically Active Males (Mean ± SD Age: 26.4 ± 4.8 Years, Weight: 77.6 ± 12.1 Kg, Height: 171.7 ± 6.9 Cm and Body Fat Percentage: 13.2 ± 6.0%) underwent Three MIT (Control, PL and CAF) on
a Bicycle, after a 6 Minutes Warm Up at 100 W; the Workload Was Increased 25 W .Min-1 Until Exhaustion, while the Pedal Cadence Was Maintained at 80 Rpm. Responses of Ventilation (VE), Oxygen Uptake
(VO2máx) and Carbon Dioxide Production (VCO2) were Obtained Throughout the Test, Breath by Breath. The VO2máx Was Determined on The Average of the last Three Higher Values During Testing. The
Mechanical Power Peak (WPEAK), Reached in each MIT Was Calculated Through the Highest Value Recorded in the Test with Correction for the Duration of each Stage. Overall (Whole Body) and Local
(Muscular) RPE were Obtained Through the 15 Points Borg Scale at the end of each Stage.
Results:VO2máx did not Show Significant Difference Was between Control, CAF and PL Session, but the WPEAK Was in CAF and PL Sessions Had an Average Increase of, 10.3 and 9.4 % in
Maximal Load (W) Greater than (P <0.05) Control Session. Absolute RPE Values, as well as the Power Output at 15-RPE (Overall and Local) were not Significantly Different among Sessions (P > 0.05).
Overall RPE/WPEAK Relationship Had a Moderate Effect Size in CAF and PL (Cohen's D=0,70 in PL and Cohen’s D=0,41 in CAF) in Relation to Control Session. Local RPE/WPEAK Relationship Was Large in PL
(Cohen's D=0,98) and Moderate in CAF (Cohen's D =0,50) in Relation to Control Session, Respectively. Nevertheless, no Difference between the PL and CAF Sessions.
Conclusions:As CAF did, PL Perceived as Caffeine Improved Performance in MIT Through a Decrease in Overall and Local RPE although this Response Was Unrelated to VO2máx.