Tennis requires anaerobic power, aerobic conditioning, strength, and agility. T e game may be played casu- ally or with great intensity and duration; thus, training and nutrient requirements vary tremendously. One (singles) or two (doubles) players are on each side. Male professional singles players must win three of fi ve sets and singles matches typically last 2 to 4 hours. Females play the best of three sets. Most singles players hit from the baseline, and long rallies require excellent fi tness. Most tournaments span 1 week, but major tournaments last 2 weeks. Most points in tennis take less than 10 seconds, but there are only 25 seconds of rest between points and 90 seconds between games, so endurance is needed for long matches. Tennis requires about 300 to 500 bursts of energy over the course of a match, so maintaining energy levels and hy- dration are critical for success. Recreational players play at a variety of intensities, and some do not have signifi cantly increased demands for energy or nutrients. Learn more about the sport at the US Tennis As- sociation website (www.usta.com).