If I've said it once I've said it a million times: "Time Under Tension (TUT) makes you STRONG". Of course saying something a million times doesn't necessarily mean that anyone is actually paying attention to what you are saying. Sometimes an "object lesson" is much more effective... and a lot more fun to watch.
Take for example the "Drunken Push Up (DPU)". Sounds like something you would do after a night of drinking Captain Morgan and Coke? Possibly - but not in this case! Imagine doing a Push Up where you start going down maximally loading the right arm (shifting as much weight as possible onto the right hand), shifting sides in the bottom (loaded) position from right to left, and then coming up on the maximally loaded left arm. For the next rep go down on the left side and come up on the right side. NOTE: stay TIGHT at the bottom and just barely hover over the ground as you switch sides. Sound easy? Great! Drop and give me TEN... nice and slow. Once you crawl up off of the floor you can finish reading this post... that's okay - we'll wait for you to finish! :)
What does the "Drunken Push Up" have to do with TUT? Everything! Most people do Push Ups as a spastic ballistic movement with their body neither loose nor tight, but some God-awful thing in between. When you are doing the DPU you have to slowly pull yourself into the bottom position, push yourself across onto the other arm, and then press up and lock out the arms. This is a slow and somewhat agonizing ordeal... and one that will make you respect TUT; maybe not immediately, although I suspect it will, but in about 24 hours when the DOMS set in and you can neither bend or extend your arms.
The long and short is this: TUT is an integral part of any grinding technique be it body weight, kettlebell, bar, sandbag, etc. Respect the grind and get the most out of load because the only person you are cheating is yourself...