Recently as I've been getting better, and playing a higher level, and more physical tennis I've noticed that I have had trouble staying in a point for the time needed. This is becoming more and more of problem for me as I am not able to last in a tight three set match, or the long important points. So do you guys have any recommendations for workouts that will help my endurance. For the past 2 weeks or so I've been running about 3.5 miles in about 40 mintues with the treadmill on a slight incline every 3 days. So should I just keep doing this or do you guys have any better suggestions. Thanks.