In today's world of competitive tennis, athletes do a lot more all-around conditioning than in years past.

Richard Geres writes

Players like Kim Clijsters, Lleyton Hewitt, and Rafael Nadal epitomize fitness. Martina Navratilova is legendary for how hard she worked on her fitness. Lindsay Davenport, Andre Agassi, and Martina Hingis each made a resurgence after working on their fitness in the second half of their respective careers.

So, what exercises are ideal for tennis players? To be fit enough to play competitive tennis at any level requires a mixture of aerobic conditioning and strength-training:

Aerobic conditioning

and agility training

Even at the club level, some tennis matches can last 3 hours (or more). Thus, it is imperative that tennis players do lots of aerobic conditioning.

Generally, the best form of aerobic conditioning for tennis involves running. Both tempo runs and intermediate-distance running should be included in the weekly routine. Running distances of 10km or half-marathons is not necessary. Develop your cardiovascular capacity by running distances of 2-3km at a relatively brisk pace. Mix in some 400 m sprints runs at near-maximal effort.

However, tennis requires more than simple straight line running. An excellent running drill for tennis is the modified shuttle run: Run from the fence to the service line, then back to the fence, then up to the net, then back to the fence. This up-and-back cycle can be repeated over and over uninterrupted. To add variety, hold your racquet while doing this drill. Another variation is to face towards the net while running both up and back (ie., this involves alternating between forward and backward running).

Agility and mobility drills are also important. One way to do this is to start by standing in the center of the court, where the service line meets the center line. From this point, run to one of the 4 corners of the court, then, back to the center, then to a different corner of the court, then back to the center, and so on. At each corner, touch your fingers to the ground. This will get you used to bending low for volleys and ground strokes.

You should do this 4-corners drill while always facing towards the net during your trek to each corner. This will mimic what you need to do when moving forward at an angle to cut off a volley, and will emphasize proper positioning when retreating to the back court. Doing this 4-corners drill while always facing forward requires you to run at angles, both forwards and backwards. This drill will also enhance your ability to change direction, something that occurs constantly in a tennis match. Once you have developed your fitness, have your partner hit a ball to each corner and see if you can return it. This will force you to get in proper hitting position when you reach each corner.

The killer drill

• First, make sure your hitting partner is good at feeding balls and start with a shopping cart full. Your partner will be feeding balls, but not trying to return them.

• Begin at the baseline. Your partner should start by feeding 2 balls to your backcourt, setting you up to hit 2 ground strokes. You should drive these balls deep, to opposite corners. Approach the net after hitting the 2nd ground stroke, but only if both of your shots landed in. If either goes long or into the net, keep hitting ground strokes until you hit 2 in a row that stay in.

• Next, your partner should feed you 2 balls that you can volley, one from each side. After you hit the 2nd volley, touch your racquet to the net and begin retreating to nail an overhead.

• Your partner should hit a lob towards the center of the court. Take this out of the air with a firm overhead.

• Move in again and have your partner hit a ball that you can volley away for a winner.

• Now, run back to the baseline and start the whole series over.

This drill goes on continuously until you run out of balls, or, are completely exhausted. It's a tough drill, but it simulates match play.

Resistance training

Even though a tennis racquet isn't heavy, weight training is now considered a core element of a serious tennis program. When Andre Agassi wanted to take his game to a new level, he hired strength coach Gil Reyes to be his personal trainer and installed a complete gym in his house. He began weight-training and eventually regained the world's number 1 ranking in 1999.

• Dumbbell exercises: Dumbbell exercises are ideal for tennis players. Exercising the shoulders with dumbbell presses and raises will improve the muscles used for serving and hitting overheads. Curls, bench press and flye exercises will improve the forehand and backhand volley.

• Cable-pulls are a great way to improve arm, back and shoulder strength for hitting ground strokes. These exercises allow for a wide range of motion which recruits a variety of muscles used in the tennis stroke.

• Core training: A really important part of resistance training for tennis is core training. The serve and the overhead smash require a lot of strength from the abdominals and the obliques. Crunches on the floor or using a stability ball and leg raises are ideal for this. And don't forget to incorporate twisting movements to involve those important obliques as well.

• Plyometrics: Once a good base of leg strength and cardiopulmonary conditioning has been achieved, add some plyometric exercises. Plyometric jumping exercises will help you jump up and back to nail that overhead smash.

If you find jumping exercises like this boring, consider playing some 2-man sand volleyball. You'll get a fantastic workout and not even realize that you are doing those very same plyometric jumps!