Your gender, age, weight and type of activity are all needed to calculate the number of calories burned. Also note that different exercises burn different amounts of calories. However, sitting on an exercise ball burns 4.1 more calories per hour than sitting on an office chair. You would need to use different muscles to balance on the ball. However, one of the links below is to a calorie calculator. I typed in your weight and 30 minutes of exercise for an aerobic activity, which an exercise ball is. It calculated 175.5 calories. You could double this number for a one hour workout.
Calories burned during exercise differs for children. A lot of the online calculators are intended to measure adult calorie expenditure.
You say that you are 12 years old and 130lbs. Your height is also an important measurement here, as this determines more closely your bmi (body mass index). Also, how many calories you are burning during exercise very much depends on how aerobic the activity is. If you are out of breath for the whole of the 30 minutes this indicates you are burning a high level of calories for you. The 30 minutes to an hour is evidently a recommended time to spend exercising on the ball, but you might find you need to build up to that, or need to make the exercise less intense at times during the workout (interval training). I would say that if you exercise too hard in an individual session, you might be put off regular exercise as you won't look forward to it as much, dread it even. Exercise should be fun as it will likely be more beneficial that way. You could listen to music while you are exercising?
This is an online calculator I found that caters for age from 13, and you can put in height, weight and gender, as well as activity. I did a calculation on this, based on a guess of your height being 5ft 2 and choosing 'gym workout' as the activity. This gave 166 calories, which is similar to what trophyhunter1 said above.
The best way to monitor how many calories you are burning from exercise, on top of normal daily activity, is to count the calories in your diet and monitor your weight. If you are still growing in height (which you might well be, being only 12 years old) this makes weight change more difficult to check. Certainly, you shouldn't make any big changes to your diet or do extreme levels of exercise without talking to your family doctor.
There are a number of factors which determine the number of calories spent. These include the age, weight, type of activity, gender, etc. There can be a number of activities one can do with an exercise ball.
With an exercise ball, the number of calories burnt are about 2.8 per minute. So a 130 pounds person while working out for 30 minutes will burn 83 calories and for 60 minutes duration, will burn 166 calories.
In comparison, sitting on a chair will burn about 112 calories per hour for a 135 pound person.
Please note that there are a number of exercise balls and a number of activities (for example, strength training, crunching, stretches, balances, etc.) that one can do with an exercise ball.
hope this helps.
im 12 years old and i weight 130
It depends on your weight, age, and what sort of ball are we talking about! ^_*
so do i burn 175.5 calories jumping on an exersise ball for an hour?