A very nice kriya, or yoga set, that works the abdominal muscles. Sleek, simple, effective. It is a fairly rigorous set, though, so unless you are in good shape, do it half time (each exercise exactly half) - 1 minute, instead of two - and make sure to rest a minute between exercises. Also, go at your own pace. It is okay to stop a moment to give those 'unworked' abdominals a rest, and then continue for the remainder of the time.
I find either the timer or the stop watch on my iPhone is a terrific way to time the exercises. That's nowadays - watching the second hand on a clock worked real well when I first began teaching yoga.
Yogi Bhajan's yoga is very structured. It is important to do all of the exercises, and for the time specified (or all for half the time or a third, just be consistent). In all the years I have done Kundalini Yoga, I have never had a 'bad Kundalini' experience, nor have I heard about this happening from any of the other Kundalini Yoga instructors that I know. Yogi Bhajan's kriyas are balanced and will help to energize you without causing the sorts of problems we have all heard about Kundalini rising in those who are unprepared for it.
Abdominal Strengthening Yoga
because I should include this when I post yoga sets
Note: Scans of these yoga kriyas and meditations have been uploaded to an unlisted album in Picasa and cannot be found by public search engines, but only if you have the link (which is available from this blog). I have begun this album so that I can easily access yoga sets and meditations I am working on. Also, all of the yoga sets in this album were given to me when I attended yoga classes and to everyone attending those sessions (or from freely downloadable on-line sources) - they are not scanned from books, which hold copyright.
If you find these sets and meditations intriguing and try them and like them, I urge you to find a Kundalini Yoga class in your area to properly learn how to do them, as well as how to tune in, the Bhandas, or body locks, the different types of breath work, and so very much more.