6. Add Burpees Between Sets
The burpee is, hands down, one of the most hardcore exercises you can do. In one compact exercise, you develop your strength, muscular endurance, and cardiovascular fitness—and it feels like it.
It just so happens that burpees are the perfect bodyweight exercise to do between weight-lifting sets. To go full-on hardcore, do a set of 10-15 burpees during your rest periods.
You’ll probably have to rest for 30-60 seconds afterward, but by supersetting your main lift with burpees, you’ll notice an increase in your overall conditioning levels. You’ll also notice that you’re no longer able to walk, talk, or lift a feather…but it’ll be worth the sacrifice.