Step-by-Step Instructions

1. 1

   Adjust the seat and chest pad so the pivot point of the machine aligns approximately with your navel or lower ribcage.

2. 2

   Secure your feet under the ankle pads and grip the handles or place your arms against the upper pads as the machine design requires.

3. 3

   Initiate the movement by contracting your abdominals to flex the spine, pulling the ribcage toward the pelvis—not by pulling with the arms.

4. 4

   Crunch down until you feel a strong peak contraction in the upper abdominals, exhaling forcefully at the bottom.

5. 5

   Return to the starting position under control, allowing the spine to extend and the abs to stretch without letting the weight stack rest between reps.

6. 6

   Focus on a 2-second concentric and 3-second eccentric tempo for maximum time under tension.

Common Mistakes

• Using the hip flexors to drive the crunch by hinging at the hips rather than flexing the spine, which loads the iliopsoas instead.

• Pulling aggressively with the arms, which recruits the lats and biceps and reduces abdominal involvement.

• Loading too heavy and performing partial reps that barely produce any spinal flexion.

• Holding the breath throughout the set instead of exhaling on the crunch, which limits intra-abdominal pressure and peak contraction.

About This Exercise

The machine crunch isolates the rectus abdominis by providing external resistance to spinal flexion in a seated, stabilized position. Unlike bodyweight crunches where resistance drops off at peak contraction, the cable or cam mechanism maintains tension throughout the full range. This makes it an effective tool for progressive overload of the abdominals, which are often undertrained with bodyweight-only protocols.