# Abdominal The seated crunch machine — loaded spinal flexion with the lower back supported. - **Category:** Main circuit - **Type:** Machine-based trunk flexion - **Targets:** Rectus abdominis, deep core - **Prescription:** 4 × 10 ## Setup Sit with the pads resting against your chest and your feet flat on the platform. Grip the handles lightly and set the seat so your hips stay tucked into the base of the back pad. ## Execution 1. Contract your abs to curl your ribs down toward your pelvis, driving the chest pad forward. 2. Pause at the bottom of the crunch, feeling the abs fully shortened. 3. Return under control until the torso is tall again — don't let the weight yank you back up. ## Cues - Curl the spine, don't just hinge at the hips — think "shorten the front". - Keep your lower back in contact with the pad throughout. - Let the abs move the weight; the arms only steady the handles. ## Common Mistakes - Pulling with the arms or shoulders instead of the abs. - Hinging from the hips with a flat, rigid spine. - Rushing the return and bouncing out of the top. ## Progression Add weight once all four sets of ten are a controlled curl; slow the lowering phase to three seconds for extra time under tension.