12. Crossfit

When we think of CrossFit, probably the gym comes to our mind along with a lot of tools. At home and without these tools, CrossFit is a little more challenging, but not impossible. Let me give you an example of a good core workout:
Complete 5 rounds of:
- Ten sit-ups
 - Five push-ups
 - 45-second plank
 - Ten push-ups
 - 60-second plank
 - Fifteen sit-ups
 - Rest 60 seconds between rounds
 
