ISOMETRICS- This is really the most important single thing you can do, even if you don't have time to do any of the above exercises, and it really can be done anywhere, at any time! This really is so incredibly simple, your going to love it!
Its based on the same principal as the Kegels, only now you'll be concentrating on different parts of your body.
Just like the Kegels, which is the flexing of your PC Muscle, now your be flexing all your other muscles.
Just pick a part of your body to concentrate with-i.e...... your angles and calf's, your thighs, ass, stomach, chest, or even tighten your facial muscles.
Flex the desired part of your body and hold the flex for 20 seconds, making sure your breathing is steady and easy. Now relax and repeat the process at least 3 times, adding more repetitions as you progress.
You can also do an entire body flex, which covers all the parts.