The kneeling power ball toss is just one way to build upper body strength.
bench press
To build upper body strength the best chest exercise is lifting weights.Dumbells are the easiest way.Start on smaller weights and build up to heavy weights.
Its exercise that involves moving your body to build muscle strength.
Throwing the discus isn't really an exercise. It's an activity. It does require a large amount of upper body strength. You can learn to build upper body strength by visiting http://www.squidoo.com/build-upper-body-muscle.
Karate is good practice for all of the body. It helps build strength and stamina.
The best way to body build is through strength training. This involves lifting weights at the gym and by utilizing the available workout equipment.
It helps the body to build strength in the core of the body which is the abs (bellow your chest). Add dumbells to your hands to increase the intensity of the workout.
It will build you upper body strength and it will test on how long you can go until you get tired. It is good for strength building and endurance training.
Softball is a power sport. It is important to build core strength, leg power and strengthen your upper body. You need strength to bat, throw and run
Try some aerobics at home. Doing everyday exercise, along with walking and jogging will improve your body skills. Push ups and or pull ups can also build body strength.
I believe the weight lifting is an excellent way for your body to build strength, but a good weight routine should be joined with a good balance diet and a stamina building exercise like cardio or Pilates.