Along with sparing you from coming in contact with the flop sweat of the bro before you, staying off the floor while working your core can also spare your back. Crunches may be an ab-building staple, but performing them—especially with added weight—can encourage your spine to round, which is terrible for guys with pre-existing back issues.

Instead, try adding resistance to your ab training with standing cable knee raises. Your spine will be in a more secure position, since it stays straight as your knees and core pull the weight up.

HOW TO DO IT

1. Attach an ankle strap to a low pulley on a cable station and wrap it around your ankle. With your opposite hand, support yourself on the station.

2. Drive your knee up past 90°, keeping your torso upright and squeezing your lower core. Hold for one second at the top, then lower back down and repeat.

TIPS

If your hip engages during the lift, compress your rib cage as you drive your knee up to activate your abs. If you still don’t feel them contracting, place the opposite hand of your working knee behind your head and bring it to your knee as you drive it up.

SEE ALSO: The 6-Week Power Abs Routine