Been living in Nashville for 4 weeks, training at my brother-in-laws gym www.templefitnessnashville.com
They have 2 tractor tires in the back lot.
One small, the other big.
We usually flip them, or drag them sled style, but sometimes when I want to do some HIIT cardio, I go out back, and gram the axe-handle sludge hammer and beat the living shit out of the big tire.
Takes all I've got.
I usually 15 minutes on the treadmil with a heart rate of 130 or so, then go out back ande nail out 10 reps left, 10 reps right - then rest for 30 seconds.
Once I get to 100 per side, I go back in side for 10 minutes coold down on the treadmill again, keeping around 130 hbpm...
Doog Dog I am tired by the end of that..