eFitnessConnection.com - Blog

Do you want a harder core?  Then try a much harder exercise.  Canadian researchers have determined that your abs work nearly as hard when you do a plank on a Swiss ball instead of on the floor.  To perform a plank, get into a pushup position, but place your forearms on the floor or Swiss ball, then contract your abs and hold.  One advise:  unless you can hold a plank for 30 seconds, you should not attempt the Swiss-ball version.  That’s because trying the advance exercise before you’re ready could strain your back.  Pass the test?  Do three to five 10-second ball planks, resting on your knees for 2 beats between sets.