Aspartate+NaHCO3 Maintain Muscle Contractility: Plus 14% Rate of Force Development, Minus 37% Ammonia Post HIT

The combination of aspartate + bicarbonate may make an involuntary rest phase on the floor of the gym obsolete.

It has been while that sodium bicarbonate, aka NaHCO3, or (pure) baking soda has made the SuppVersity news. The ergogenic aid recently made the TOP-list of "supplements with good to strong evidence of achieving benefits to performance when used in specific scenarios" in the published "IOC consensus statement: dietary supplements and the high-performance athlete" (Maughan 2018) - a short list in which bicarbonate is listed next to caffeine, creatine, nitrates, and beta-alanine, and a list which doesn't include aspartate as a putative congenial synergist, yet.  Aspartate, a salt or ester of aspartic acid is a nonessential amino acid that has a central role in hepatic glyconeogenesis as it is the substrate to the aspartate aminotransferase enzyme in the liver, an enzyme of which you know that it is significantly elevated by (intense) training (learn more).
Aspartate has been mostly ignored by researchers in the past decades - probably because the follow-up studies to the initially promising research from the 1950s-60s (Laborit 1957 \ not available online), which suggested that aspartate supplements can successfully combat the exercise-induced rise in ammonia (a byproduct of protein breakdown the build-up of which in your blood has been implicated as one of triggers of progressive fatigue | Butch 1983; Wilkinson 2010) yielded mixed, often negative results which have been reviewed most recently 10 years ago by François Trudeau (see Table 1).

Table 1: The effect of aspartate on endurance and ammonia (positive results | Trudeau 2018)

Unfortunately, the overview in Table 1 represents only approx. half of the studies - the studies with positive outcomes - in Trudeau's review. The other half of the studies found no effect.

Figure 1: Overview of the experimental protocol. There were five sessions of a test-exercise-test sequence of quad force pre-testing, HIT, and quad-force post-testing. The first of these sessions served as a familiarization trial that was also used to establish an individual challenging exercise volume for all following sessions - this means: in all subsequent sessions, the subjects had to perform the exact same number of reps they were able to perform in the first session (based on my understanding of Farney 2018).

In this context, it seems to be worth quoting a finding of Trudeau's previously cited 2008 review which found that "[t]he effect of aspartate on endurance seems more plausible in humans and less supported by animal studies" - that's the way we like it, no?

What did the scientists do and what were the outcomes of this new study, then?

I can understand if you're still not very excited. So, let's take a look at the study design and outcomes, before deciding whether aspartate is a supplement that's missing from pre-workout stack or whether you're rightly skeptical and aspartate isn't worth trying.

The authors of the study under review (Farney 2018), scientists from the Texas A&M and the Louisiana State University, recruited 12 trained participants (minimum 6 months of combined cardio + weight training  exp.; age: 21.9 +/- 1.5 years; height: 1.77 m; and body mass: 82.4 kg).
One of the initially twelve subjects had to be removed from data analysis because of gastrointestinal tract complications (missed the SuppVersity tips to stomach sodium bicarbonate ;-), the others completed all exercise and testing sessions successfully.

Figure 2: Change (%) in relative force development and peak force (calculated as the rel. change in the given treatment minus the relative change in placebo) in std. tests conducted pre- to post-CrossFit-esque HIT protocol (large) | Relative difference (vs. placebo) in time it took to perform the HIT-workout (small inset | calculated based on Farney 2018).

Based on the data from the pre- and post- isometric thigh pull tests as well as the timed, individualized HIT workout (three rounds of barbell thrusters, squat jumps, lunge jumps, and forward jumps), I've calculated the relative pre- vs. post-test changes and plotted them expressed relative to the placebo group in Figure 2. This form of presentation may not be the most common one, but it illustrates the individual treatment effect better than the absolute rel. changes (pre-to-post, not relative to placebo) which were...

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  for the rate of force development, a 10% plus! in the ASP + NaHCO3 group and reductions of -4% in the NaHCO3 as well as the placebo group and a surprising -7% in the ASP group and...
• for the peak force, a complete amelioration of the (expected) performance decline in the ASP + NaHCO3 trial and reductions of -3% in the NaHCO3 and -5% in the ASP as well as the placebo trial.

References:

• Ahlboro, Björn, Lars‐Göran Ekelund, and Carl‐Gustaf Nilsson. "Effect of Potassium‐Magnesium‐Aspartate on the Capacity for Prolonged Exercise in Man." Acta Physiologica Scandinavica 74.1‐2 (1968): 238-245.
• Bucci, Luke R. Nutrients as ergogenic aids for sports and exercise. Vol. 2. Crc Press, 1993.
• Mutch, B. J. C., and E. W. Banister. "Ammonia metabolism in exercise and fatigue: a review." Medicine and science in sports and exercise 15.1 (1983): 41-50.
• Farney, Tyler M., et al. "The Effect of Aspartate and Sodium Bicarbonate Supplementation on Muscle Contractile Properties Among Trained Men." Journal of strength and conditioning research (2018).
• Laborit, H., et al. "Effect of the ionic composition of the extracellular medium and compared effect of aspartic acid, aspartate of potassium and glucose on the swimming test of white rats." Comptes rendus des seances de la Societe de Biologie et de ses Filiales 151.7 (1957): 1383-1386.
• Maughan, Ronald J., et al. "IOC consensus statement: dietary supplements and the high-performance athlete." International journal of sport nutrition and exercise metabolism 28.2 (2018): 104-125.
• Mutch, B. J. C., and E. W. Banister. "Ammonia metabolism in exercise and fatigue: a review." Medicine and science in sports and exercise 15.1 (1983): 41-50.
• Trudeau, François. "Aspartate as an ergogenic supplement." Sports Medicine 38.1 (2008): 9-16.
• Wesson, Matthew, et al. "Effects of oral administration of aspartic acid salts on the endurance capacity of trained athletes." Research Quarterly for Exercise and Sport 59.3 (1988): 234-239.
• Wilkinson, Daniel J., Nicholas J. Smeeton, and Peter W. Watt. "Ammonia metabolism, the brain, and fatigue; revisiting the link." Progress in Neurobiology 91.3 (2010): 200-219.