Running with a rock does nothing more than trash your knees. Throw that bad boy in a ruck and have at it, but jog don't run, use the rocking chair heel to toe method.
It doesn't do you a bit of good to tear your body down when you are trying to build it up. Here's a hint "Stairmaster". (1) hour on the stairmaster at a medium continuous pace works wonders for endurance, leg strength and your core! There's hard and there's stupid. Train smart!
