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.
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