Strength Training - Step Ups Jumps and All That Stuff

I've got a pair of very rusty very old dumbbells which yeah bit the way to keep falling off but you know I try and do stuff with that. The older you get the more quickly you lose the stuff you're not using is this because at one point someone tells you like if you're just running slowly or medium the whole time you're just watering a third of your garden. You have to have a system around now that I quite often do that - think well I've got to do a bit of fast stuff so they're running it from here to there, I'll run  that sort of thing. It's kind of fun as well isn't it? If you