Sworkit. This is a FREE app on your iOs device, android device or computer. I have been checking this app and I am very impressed for older children through adults.
Basically you choose what type of a work out you are looking for - strength training, yoga and stretching. You choose your workout length and the area of the body you would like to exercise. Then it is all set to go. The timer starts and you being the exercise for the time allotted. If you are not sure how to perform the exercise just click on the video icon and you can view a video of the exercise.
This is a wonderful to add to your collection of apps that promote physical activity.
What a simple quick brain break for the classroom as well.
If you have a child using it, they can email you their results of how many minutes they worked out.
Want to read more? Check out 10 Apps that Get You Moving.