8 Trainer-Recommended Isometric Ab Exercises to Light Up and Completely Exhaust Your Core

The challenge of this tough static hold is to keep your lower back pressed against the ground the whole time, said Eric and Ryan Johnson, NSCA-certified trainers from Homage Fitness.

• Begin on your back with your legs straight and your arms extended overhead.
• Actively press your lower back into the floor and draw your belly button into your spine.
• Inhale to slowly lift your shoulders, arms, and legs off the floor. Keep your hands and heels as low to the ground as possible, while still pressing your lower back into the floor. Maintain tight abs and glutes. It's OK to bend your knees if straight legs are too challenging.
• Hold like this for five to 30 seconds to complete one rep.