Couple notes on what I have been doing lately:
The Tabata Method I use during GPP is taken from Dan John
Check this article out if you got time....
The sledgehammer work is done with an EZ curl bar with weight on one end! I don't own a sledgehammer and I am too cheap to buy one, so I had to improvise.
Why do I do it? Because I hate normal cardio, and I was trying to find activities to get my heartrate up inside during the winter. When nicer weather returns, I plan on doing sled pulls (with a tire, rope and weight....again, improvised, kind of like this but no where near as nice.... http://patrickhdonnelly.blogspot.com...tire-sled.html
) and farmer's walks as well.
Finally, I have been doing Chin-ups 3 times daily to "Grease the Groove" (much thanks to MaverickBU for mentioning this article in another thread)
I started with 3x5 (my max is 14 with BW) because it is about synaptic facilitation and the sets are not supposed to be hard. I do 1 in the morning, afternoon and evening. I add one rep each week and I am currently doing 3x7.