HR100C. Omron Heart Rate Monitor. Heart Rate Watch. Sports fitness. Sports conditioning. Sports health. Personal wellness. Tennis fitness. Tennis conditioning. Tennis health. Tennis wellness. Endurance training for tennis requires enough aerobic conditioning to see you through three long sets. To avoid overuse injuries, mix up aerobic activities - running, swimming, stairclimbers, elliptical trainers and such. Knowing your heart rate during the aerobic activity is important because if you are working out too hard, your activity can become counter productive and strain muscles. To achieve an effective workout, no matter what the aerobic activity, you must maintain your heart rate at a proper level for a minimum of 20 minutes. The proper level is generally 65%-85% of your maximum heart rate. ''To be a great tennis player, you need speed and quickness to get to the ball, and the cardiovascular conditioning to go the distance.'' - Tennis Magazine The Omron? Heart Rate Monitor is easy to pr