. For My "Cardio" I have recently started doing, what I call my "Work Capacity and conditioning (aka GPP) Training Circuit Matrix". The general idea I got from the IntoCombat folks who train Boxers, MMA, etc.
Basically it is Circuits of 4 exercises/stations done for a set time done as quickly as possible maintaining good form and making it through each period without needing rest. I use 5 Circuits (Lower Body, Upper Body, Core/Rotational, Speed/Agility, and Sport Specific). Each can be done 2 or 3 times/rounds. Any exercise can be used as long it fits the frame work.
Medicine balls, light dumbbells, bodyweight, Old School Calisthenics, jump ropes, Light weight Complexes, agility ladders, hurdles, stability balls, plyometric boxes, etc. all work fine. Currently I do each station for 20 seconds on/ 10 seconds off with 1 minute rest between rounds and 2 minutes between circuits. The matrix is completely scalable, by changing exercise selection, number of rounds, length of exercise, length of rest, etc.
I do this twice a week on Tues and Thurs and use two different sets of exercises/matrixes. This is primarily for cardio, so I choose exercises that can be done fairly quickly. Secondary benefits of the circuits include anaerobic endurance, dynamic power, speed, coordination, etc. I weight train on Mon, Wed, Fri and I seem to be able to recover just fine.
The Sport Specific circuit is just heavy bag work I do for fun, if you compete in some sport Im sure there are some aerobic exercises/ drills for that sport that you could use.
I know my description may sound confusing so I have included a link to my log for this. The log is in Excel format. The third worksheet is a blank.
I also have included a partial picture of it below (hopefully)