USTA Chicago manages Adult League—the country's largest adult competitive tennis league—for teams at all levels throughout the district. And we have many other playing opportunities too. Try Cardio Tennis! Cardio Tennis is a high-energy fitness activity that combines the best features of tennis with cardiovascular exercise, delivering the ultimate, full body, calorie-burning aerobic and anaerobic workout. Check out our Flex League provider, Gladiator Tennis, to participate in singles and doubles leagues on your own schedule. Healthy beats. Healthy bodies. Healthy vibes!