Plyometrics?

A few weeks ago, my friends at SBRC sent around an email to see if there was any interest in a once a week core and plyometrics class in Brooklyn Bridge Park.  A few years ago I made a twice a week core class part of my routine and it made a huge difference in my mechanics.  I stopped when tri training substituted swimming for situps.   Mostly that's been a good thing, but I have been wondering if some of my recent issues could be remedied with core work.  So, I expressed interest.  I did this without doing any research into the meaning of the other word in the class title -- "plyometrics."  It sounded like pliable, so I assumed it meant stretching.  Stretching is good too. Oops! I was wrong.   Plyometrics is another word for  "jump training."  It involves jumping onto things, jumping off of things, jumping up and down, sprinting, skipping, running with high knees, doing grapevine steps, lunging, and jumping some more.  OOOOPPPPPPHHHH!!  It was a beautiful morning, and I didn't get hurt, so we'll see over the next few days whether this is a good addition to the workout.  I did a few miles afterwards, and it seemed to to have smoothed out my form a bit.  I think it is good for opening up the hips and getting the glutes to fire.  I certainly looked silly enough doing it.  :-)  Do any of you have experience with this?? did it help?