Preworkout supplementation is more common than ever before, here is a nice double-blinded paper on such. Some ingredients have shown strong evidence for enhancing subsequent performance. Caffeine has shown an ergogenic effect (at the dosages of 3-6 mg/kg of body weight) on strength, power, and endurance. Caffeine may enhance performance by “…(a) alteration of fat metabolism, (b) direct effect on calcium release from the sarcoplasmic reticulum (ryanodine receptors), and (c) adenosine receptor antagonism.” By altering the sensitivity of adenosine receptors, the perception of fatigue is reduced while training/competing.
Other supplements, such as citrulline have improved muscular endurance or reps-to-failure in lower body compound movements at 60% 1RM. Leucine is a key amino acid which enhances muscle protein synthesis, decreased levels of reported soreness, and enhances cognitive function. As we combine these various ingredients we may observe positive synergistic effects, as seen with beta-alanine and creatine in conjunction with caffeine delaying neuromuscular fatigue. On the contrary, it would be reasonable to suggest some ingredients blunt the ergogenic effects of others.
The purpose of this study was to observe the acute effects of multi-ingredient preworkout supplementation on:
- Total-, lower-, and upper-body volume of resistance exercise
- Subsequent lower- and upper-body strength and power
- Anaerobic work capacity
12 men with a mean age of 22 years (±3 years), height of 179cm (± 7 cm), body mass of 86 kg (± 13 kg) were recruited. All subjects had been resistance training at least 3 days/week for a minimum of 1 year. All men were able to back-squat at least 1.5 times their body mass to be included. The mean 1RM back-squat among participants was 142 kg (± 34 kg) or 1.7 x body mass (± 0.3).
Whole-body DXA scans were used to assess body composition.
1RM strength testing included 4 upper-body (flat bench press, bentover row, incline bench press, and standing shoulder press) and 4 lower-body (back squat, deadlift, front squat, and reverse lunge) barbell movements. This data was compiled to further extract the training intensities for future sessions. A standardized warm-up began with 10 repetitions at 50%, 5 repetitions at 70%, 3 repetitions at 80%, and 1 repetition at 90% of each subject’s predicted 1RM body mass.
Lower body power was assed through 3 counter-movement jump attempts using a Vertec vertical jump device. Upper body power was assessed with 3 trials of a bench-throw test in a smith machine, using 30% of the barbell bench 1RM.
Isokinetic testing was also assed using a Biodex System 4. Both knee extension and flexion were performed at maximum concentric effort on the dynamometer at 30°/second. Peak torque was recorded from 3 trials.
Anaerobic capacity was assessed using a Monark Cycle Ergometer. After a 5 minute warm-up, a 3-minute all-out-effort test began with a resistance of 4.5% body mass at a cadence of 110 revolutions/minute, followed by the fastest possible cadence for each subject.
The resistance training protocol consisted of 5 visits were the subjects performed a lower-to-upper body superset. 4 sets of 10 reps were performed for each movement at 75%. This is depicted below in figure 2.
Supplementation was double-blinded, as an independent investigator prepared the placebo (PL) and supplement (SUP) drinks. The subjects were randomly assigned to ingest the PL or SUP during visit 4, then the crossover on visit 5. The Muscle Pharm preworkout supplement “…contained citrulline-malate (6 g), leucine (4 g), aspartic acid (3 g), creatine hydrochloride (2 g), beta-alanine (1.6 g), tyrosine (1.2 g), and caffeine anhydrous (350 mg).” The PL was a maltodextrin and 12oz water mix.
Total body and lower body volume of exercise was significantly greater in the SUP group; although upper-body volume was minimally different. SUP also edged out PL in vertical jump, isokinetic leg extension peak torque, and bench throw velocity. Anaerobic work capacity showed no significant differences among groups.
The greatest finding from this paper was the increases in total body volume (9%) and lower-body volume (14%), compared to the PL. The greatest differences were observed in the first superset of back squat and bench press (~16%), which was approximately 45 minutes after ingestion. Researchers largely attribute the results of the study to the effect caffeine has on ratings for perceived exertion (RPE). The average dosing of caffeine was 4.2 ± 0.6 mg/kg of body weight.
Preworkout supplementation may be beneficial for enhancing the volume of the subsequent resistance training session. It is not totally clear how the various ingredients interact, but much of the effects are attributed to a few primary ingredients such as: caffeine, citrulline, beta-alanine, creatine hydrochloride, and amino acids.
Reading this paper reminded me of an infographic created by Dr. Yann Le Meur, French sport scientist. It is not all-inclusive, but does set the foundation for a solid supplement cheat-sheet. If you are at all curious about the paper he is referring to, it can be found here.
Original Table by Close et al. (2016):
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