“Quercetin Increases Brain and Muscle Mitochondrial Biogenesis and Exercise Tolerance.”  Am J Physiol Regul Integr Comp Physiol.2009.  Davis et al., University of South Carolina.  
A pre-clinical study examined the effects of 7-days of quercetin supplementation on markers of mitochondrial biogenesis.  Results indicate that quercetin supplementation enhanced mitochondrial biogenesis - the production of cellular mitochondria - in the muscle and brain. This increase in mitochondria was associated with an increase in both maximal endurance running capacity (VO2max) and active involvement in physical activity with the mice being more willing to exercise.
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“Dietary Antioxidant Supplementation Combined with Quercetin Improves Cycling Time Trial Performance.”  International Journal of Sports Nutrition and Exercise Metabolism, 2006, 16, 405-419. MacRae and Mefferd, Pepperdine University.   
An independent, double-blind, placebo-controlled crossover study on the effect of FRS on cycling performance in eleven elite cyclists showed a 3.1% improvement in time to complete a simulated 30km mountainous time trial when subjects consumed  FRS for a 3 week period.
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“Dietary Flavonoid Quercetin Increases VO2max and Endurance Capacity”  International Journal of Sports Nutrition and Exercise Metabolism. Davis, Carlstedt, Chen, Carmichael, and Murphy, University of South Carolina .   
An independent, randomized, double-blind, placebo-controlled, cross-over study showed that when 12 healthy, active (but not highly trained) men and women consumed 500 mg of quercetin (QU995™) in an enriched drink mix twice daily for 7 days, they experienced a 13.2 percent increase in ride time to fatigue (based on bicycle endurance capacity) and a 3.9 percent increase in VO2max (maximum oxygen consumption) .
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