When it's time to choose a liquid chug after a long, tough workout, there's a slew of options out there. Water? Gatorade, POWERade, or All Sport? Endurox R4? Physiologist Joel Stager, director of the Human Performance laboratory at Indiana University, has even one more potential workout recovery drink to add to the list: chocolate milk. His latest study, published in this month's International Journal of Sport Nutrition and Exercise Metabolism, names this kids' favorite an optimal post-exercise recovery aid.