Coffee Beats Caffeine in the Gym: More Reps + Higher Total Volume on Squats Due to Ingredients Other Than Caffeine

You don't necessarily have to bring fresh beans to the gym. A simple Nescafé instant coffee will serve the purpose, study shows. And it's going to work better than equal doses of straight caffeine.

As a SuppVersity reader you will know that coffee is much more than a brown liquid that contains caffeine. Many of its proven health effects I have discussed here and in shorter news items on Facebook are after all related to the combination of anti-oxidant and stimulant agents in coffee - a brew that is so much more than just the sum of it parts.

Against that background it is only logical that Darren L. Richardson and Neil D. Clarke from the Department of Applied Sciences and  at the Faculty of Health and Life Sciences of the Coventry University in the UK wanted to expand on the previously reported results by Trexler et al. (2015 | previously mentioned at the SuppVersity).
Trexler et al. found that coffee improved leg press 1-RM performance to a greater extent than caffeine, while both coffee and caffeine attenuated the reduction in total work performed compared with placebo. Accordingly, Richardson and Clarke started their research, which was a randomised, latin-square, crossover, placebo-controlled trial, in which each subject attended the strength and conditioning suite on six occasions, with the hypothesis that the ingestion of coffee would exhibit at least some advantages over a equally dosed caffeine "placebo".

Figure 1: Graphical illustration of the experimental protocol on all five test occasions (Richardson. 2016).

To test this hypothesis, the researchers recruited nine resistance trained males [(Mean±SD age: 24±2 years, weight: 84±8 kg, height: 180±8 cm, 1-RM for the squat (135±28 kg) and bench press (102±20 kg)]. Each subject attended the strength and conditioning suite on six occasions, the first being a familiarisation session to establish one repetition maximum (1-RM) for the squat and bench press, before they completed five sessions of the same the experimental resistance training protocols.

"Trials were performed within half an hour on separate days to ensure an accurate comparison of strength and to limit strength fluctuations due to the effects of circadian variation (Duncan. 2011). Trials were separated by at least two days in order to allow recovery and to ensure complete caffeine washout. As caffeine has a highly variable half-life in healthy individuals of between 1.5-9 hours (Syed. 2005) subjects were instructed to avoid caffeine ingestion for a minimum of 12 hours and strenuous exercise for 24 hours prior to each trial to avoid fatigue (Beaven. 2013).

The actual exercise protocol consisted of squats and bench presses at 60% 1-RM until failure.  Each subject performed the exercise protocol following the ingestion of...

• 0.15 g/kg caffeinated coffee (COF; 3.4g per 100g coffee = 5.1g/kg body weight), 
• 0.15 g/kg decaffeinated coffee (DEC; 5mg caffeine per kg coffee = almost zero), 
• 0.15 g/kg decaffeinated coffee plus 5 mg/kg anhydrous caffeine (D+C), 
• 5 mg/kg anhydrous caffeine (CAF), or 
• a placebo (PLA; 5 mg·kg-1 maltodextrin from MyProtein, Manchester, UK).

Decaf? Well, the reason the scientists did use both, straight caffeinated and decaffeinated coffee with caffeine should be obvious: Unlike the comparison of Nescafé original (3.4g of caffeine per 100g) vs. its decaffeinated version coffee, the comparison of DEC with D+C ensured identical polyphenol concentrations in the decaf-base.How to make the most of coffee or caffeine pills... time them correctly. If you haven't done so or cannot remember the conclusions I have drawn in my article on caffeine / coffee timing, I highly suggest you head over to this SuppVersity Classic to (re-)read it!That's something which cannot be guaranteed for the caffeinated vs. decaffeinated versions of the same brand of coffee.

"[In all] trials [coffee poweder and caffeine] were dissolved in 600 ml of hot water (68.9±2.5ºC) and served in mugs. The anhydrous caffeine and placebo trials were provided in capsule form (two opaque gelatine capsules) and ingested with 600 ml of water (16.4±3.8ºC). At the start of each trial, subjects had a maximum of 15 minutes to fully consume either the treatment beverage or capsules and water and were then required to rest for the remainder of the hour, after this time the warm up began. [...]  A 24-hour dietary recall was completed by each subject during the familiarisation session, and was photocopied and handed back to the subjects in order for the same diet to be followed prior to subsequent trials" (Richardson. 2016).

Let me briefly do the math for you: With the dosages and body weights mentioned before, subjects in all caffeine groups ended up receiving roughly the same amount of caffeine (when there was caffeine in the beverage), namely: COF: 433±40 mg, DEC: 2±0 mg, D=C: 425±39 mg, CAF: 425±39 mg.

Figure 2: Changes in total weight lifted in response to the 5 treatments (Richardson. 2016).

Against that background it is all the more interesting that the coffee and decaf + caffeine group had a significant edge during squats (see Figure 2, right). "Isn't it strange, then that we don't see the same benefit on the bench?", you may be asking yourself, now... No, it isn't! Neither Beck, et al. (2008) nor Hendrix et al. (2010, bench press was part of a circuit training her) found benefits of caffeine supplementation on bench press performance in trained individuals, in similarly designed studies.
Duncan, et al. (2011) who conducted a very similar study 3 years later, however, found performance increments for the upper body, too (~10% increased total volume in the caffeine trial). Whether this difference to the previously mentioned studies by Beck et al. and Hendrix, et al. can be explained by the fact that Duncan et al. required their likewise trained subjects to be "only moderate caffeine users (ingesting approximately 200 mg·d-1, range 169-250 mg·d-1)" (Duncan. 2011), remains to be seen. While this is in fact ~100mg less than the average intake of the subjects in the study at hand, i.e. Richardson & Clarke (2016), other studies appear to suggest that the habitual caffeine intake has less influence on the performance effects than you would think.

Figure 3: Individual effect on weight lifted during both trials (left) and mean felt arousal (right | Richardson. 2016).

An alternative, but similarly speculative explanation for the differences may be that the effects of caffeine on upper body and eventually less taxing exercises is not as relevant as it is for squats. Thus the overall effect could be more pronounced during leg exercises and the benefits for bench presses and co too small to reach statistical significance in view of the fact that all studies appear to suggest that there are hyper- (like the guy on top of Figure 3, left) and almost-non-responder which mess with the statistical significance of the data.
References:

• Beaven, C. Martyn, et al. "Effects of caffeine and carbohydrate mouth rinses on repeated sprint performance." Applied Physiology, Nutrition, and Metabolism 38.6 (2013): 633-637.
• Beck, Travis W., et al. "The acute effects of a caffeine-containing supplement on bench press strength and time to running exhaustion." The Journal of Strength & Conditioning Research 22.5 (2008): 1654-1658.
• Buscemi, S. I. L. V. I. O., et al. "Dose-dependent effects of decaffeinated coffee on endothelial function in healthy subjects." European journal of clinical nutrition 63.10 (2009): 1200-1205.
• Duncan, Michael J., and Samuel W. Oxford. "The effect of caffeine ingestion on mood state and bench press performance to failure." The Journal of Strength & Conditioning Research 25.1 (2011): 178-185.
• Hendrix, C. Russell, et al. "Acute effects of a caffeine-containing supplement on bench press and leg extension strength and time to exhaustion during cycle ergometry." The Journal of Strength & Conditioning Research 24.3 (2010): 859-865.
• Huxley, Rachel, et al. "Coffee, decaffeinated coffee, and tea consumption in relation to incident type 2 diabetes mellitus: a systematic review with meta-analysis." Archives of internal medicine 169.22 (2009): 2053-2063.
• Niseteo, Tena, et al. "Bioactive composition and antioxidant potential of different commonly consumed coffee brews affected by their preparation technique and milk addition." Food chemistry 134.4 (2012): 1870-1877.
• Syed, Shariq A., et al. "Multiple dose pharmacokinetics of caffeine administered in chewing gum to normal healthy volunteers." Biopharmaceutics & drug disposition 26.9 (2005): 403-409.
• Trexler, Eric T. Effects of creatine, coffee, and caffeine anhydrous on strength and sprint performance. THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL, 2015.
• Wedick, Nicole M., et al. "Effects of caffeinated and decaffeinated coffee on biological risk factors for type 2 diabetes: a randomized controlled trial." Nutrition journal 10.1 (2011): 1.