A study with 12 participants showed that 1000 mg/day quercetin for 14 days after high exertion led to significantly less muscle soreness and significantly higher performance. (Ilenia Bazzucchi, Federica Patrizio, Roberta Ceci et al.: The Effects of Quercetin Supplementation on Eccentric Exercise-Induced Muscle Damage. In: Nutrients, 2019, 11(1), S. 205; doi:10.3390/nu11010205)
In this study (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4531078/) it was shown that quercetin is able to reduce the number of senescent cells in the body.