Coffee But Not Anticipation of Coffee Alters the Outcome of Explosive Bench Pressing

Abstract

When administering a drug, the degree of anticipation influences perceptual outcomes in migraine research (Slavenka Kam‐Hansen, 2014). Specifically, pain scores vary depending on the information given (percent anticipation). Little is known, however, to what extent anticipation affects physical performance. Often, coffee and caffeine research include a 50% anticipation in the form of experimental beverage or placebo. Few coffee studies, though, also include a true control such as water. The purpose of this study was to compare a highly‐caffeinated instant coffee (VIA) to both an identical decaffeinated placebo (DCF) and to water (WTR). This provides the typical 50% anticipation comparison and a 0% anticipation true control. We hypothesized that VIA would increase explosive performance compared to both DCF (50% anticipation) and to WTR (0% anticipation). Further, we hypothesized that DCF (50% anticipation) would increase performance and psychostimulant variables compared to WTR (0% anticipation). Ten resistance‐trained participants with varied levels of coffee habituation were tested at 50% of one‐repetition maximum (1RM) in the Smith bench press 60 minutes after ingesting 20 oz. (2 packets) VIA, DCF, or WTR. Force, bar velocity (VEL), power (POW), rate of force development (RFD) and time to peak power (TPP) were measured using the Smith bench press and a Ballistic Measurement System (BMS, Innervations, Inc., South Australia). Psychostimulant testing included Likert‐type (1–5 scale) ratings of alertness, focus and energy. After repeated measures analysis of variance and Newman‐Keuls post hoc testing, VEL and POW increased after consuming VIA versus DCF or WTR (mean ± SE: 1.15 ± 0.05 m/s vs. 0.99 ± 0.05 m/s and 1.01 ± 0.05 m/s; p=0.004 and p=0.005, respectively and 561.1 ± 109.4 W vs. 482.2 ± 92.4 W and 465.4 ± 84.7 W; p=0.009 and p=0.007 respectively). No performance differences were noted between DCF and WTR. Upon psychostimulant analysis, VIA increased alertness compared to DCF and WTR (4.22 ± 0.22 vs. 3.44 ± 0.29 and 2.94 ± 0.34; p=0.006 and p=0.0004 respectively). There was a trend for DCF to increase alertness versus WTR (3.44 ± 0.29 vs. 2.94 ± 0.34; p=0.06). Within the limitations of this design, we conclude that our hypothesis regarding VIA and physical performance was supported but the hypothesis involving anticipation of DCF largely was not. DCF had no effect on explosive physical performance but did tend to affect perception of alertness.