Adding an extra rep to your max bench press is exciting. Adding more reps to your max number of sit-ups? Not so much. After you've achieved a certain level of fitness, that's just boring and unproductive.

So how can you make your core training more challenging? Try these. They'll not only make your abs look better, they'll also teach you to develop full-body tension that translates over to your big lifts.

Plank Plate Shuffle

  • Grab three 2.5 or 5-pound plates. Stack them on top of each other.
  • With your opposite hand, bring the plates over one at a time to the opposite side of your body.
  • Work on not moving your hips at all.

TRX Body Saw

  • Set up the TRX so that when your legs are "in" you're parallel to the ground.
  • Push your legs back as far as you can without going into low-back extension.

Sandbag Pull-Through

  • This can be done in the push-up position or the bear crawl position.
  • Pull the sandbag to the other side of your body without rotating your hips.
  • Put a weight on your back to make this even more challenging.

Plank Push-Pull

  • In the plank position, instruct your partner to provide resistance as you push out, then again provide resist as you row in.
  • No partner? You can use a cable station.

Wall Plank

  • Find a spot on the wall where you can put your feet up.
  • Make sure your body is parallel to the ground and hold the plank position.

Deadbug with Plate

  • Grab a 25-pound plate and assume the deadbug position.
  • Flex at your shoulders so the weight goes over your head. The further back the harder this will be.
  • Make sure your low back stays in contact with the ground the entire time.
  • Bring one leg out and hold.
  • Try putting both legs out or strapping on leg weights to make this more challenging.

Earthquake Bar Offset Isohold

  • Attach a kettlebell to one side of the bar. Be careful that it doesn't tip.
  • Unrack the weight and resist side bending.
  • This can be done with a regular bar as well.

Related:  Nasty Ab Training

Related:  11 Ab Exercises You'll Love to Hate