Deceptive Caffeine Shows Limited Impact on Short-Term Neuromuscular Performance

TL;DR

A study found that deceptive caffeine ingestion had little effect on short-term exercise performance, except for a small improvement in repetitions to failure during bench press.

Contribution

The study evaluates the placebo effect of deceptive caffeine ingestion on neuromuscular performance in physically active individuals.

Findings

Deceptive caffeine ingestion had minimal impact on jump and ballistic bench press performance.

Repetitions to failure improved by approximately 1 repetition during bench press at 75% of 1RM.

Side effects like increased activeness and nervousness were reported in some participants.

Abstract

Background: Deceptive caffeine ingestion has shown inconsistent effects as an ergogenic aid for short-term exercises. Objective: Therefore, the aim of this study was to evaluate the potential placebo effect of deceptive caffeine ingestion on short-term performance during countermovement and repeated-jump tests, as well as bench press throw and bench press-to-failure assessments, and to document any associated side effects. Methods: A repeated, randomized, and counterbalanced design was implemented to compare the effects of ingesting a placebo claimed to be caffeine with a control condition in which no substance was consumed. Twenty-five physically active young adults (17 men and 8 women) completed a countermovement jump (CMJ) test, a 15 s repeated-jump test, bench press throws at 25%, 50%, and 75% of 1RM, and a bench press-to-failure test at 75% of 1RM and also completed a questionnaire regarding potential side effects. Results: Performance was similar between the placebo and control in the CMJ (38.1 ± 6.8 vs. 37.5 ± 6.8 cm; p = 0.225; d = 0.25) and in the 15 s repeated-jump test (p > 0.05; trivial–small effects). In the bench press throw, propulsive mean velocity did not differ at 25% 1RM (p = 0.296; d = 0.23) or 50% 1RM (p = 0.626; d = 0.10). However, deceptive caffeine ingestion increased propulsive mean velocity at 75% 1RM (0.500 ± 0.131 vs. 0.480 ± 0.131 m/s; p = 0.024; d = 0.48) and increased repetitions to failure at the same load (11.9 ± 3.7 vs. 11.0 ± 3.1; p = 0.047; d = 0.42). Mean velocity during the first 3 repetitions tended to be higher with the placebo (p = 0.064; d = 0.39), while final repetitions were similar (p = 0.469; d = 0.15). The most common side effects were increased activeness (34.8%) and nervousness (17.4%). Conclusions: In summary, deceptive caffeine ingestion had minimal impact on jump and ballistic bench press performance in physically active individuals. However, repetitions to failure were improved by ≈1 repetition (+8.2%). These findings suggest that the placebo effect of caffeine is unlikely to serve as a reliable strategy for enhancing short-term exercise performance.

Figures