We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
Plyometric calisthenics entail more-or-less explosive, usually full-body, movements. Other examples might be jumping burpees, donkey kicks, jumping lunges, high-box step-ups, high wall-balls, and squat jumps.
As I become fitter, my ability to do box jumps is improving. I am now able to do a good series of 18" box jumps. The young athletes I see get much higher. Although these are muscle- and agility-training exercises, they are also HIIT cardio. 15 box jumps gets my heart pounding through my chest. (My gyms use soft boxes, to avoid bleeding shins. Crossfit uses hard boxes, of course.)