In a double-blind, 1995 study, seven healthy young male athletes exercised to exhaustion on a cycle ergometer after ingesting either the salts of aspartic acid or a placebo. The time to exhaustion was significantly increased following aspartate ingestion, 87.6 ± 4.3 min vs. 75.7 ± 11.9 min in the placebo condition (p<.025). The researchers concluded by suggesting that K and Mg aspartic acid salts were useful as an ergogenic aid under the conditions found in this experiment.
References:
Melvin H. Williams. (1995) Nutritional ergogenics in athletics. Journal of Sports Sciences 13:sup1, pages S63-S74. https://www.tandfonline.com/doi/abs/10.1080/02701367.1988.10605509