Crunch Progression:

By Brent Brookbush MS, PES, CES, CSCS, ACSM H/FS

Function: The crunch is an excellent exercise for increasing dynamic strength of the spinal flexors, and increasing hip stability and control. Although many variations of the crunch include hip flexion, these variations should be avoided due to the increase in psoas activity. All progressions described below are done while maintaining an isometric contraction of the glute max to reciprocally inhibit psoas activity. When this exercise is performed well, it can be an excellent way to strengthen the anterior oblique subsystem, and increase core performance.

Kinesiology:

Trunk Flexion – (The Crunch)

• Agonists – Rectus Abdominis
• Synergists – External Obliques, Internal Obliques, Psoas
• Antagonists – Erector Spinae (Iliocostalis, Longissimus, Spinalis), Latissimus Dorsi
• Neutralizers – External Obliques and Internal Obliques when bilaterally contracted neutralize rotation.
• Stabilizers – Quadratus Lumborum & Intrinsic Stabilization Subsystem (Transverse Abdominis, Diaphragm, Pelvic Floor (levator ani, coccygeus), Multifidus, Rotatores, Interspinales, Intertransversarii)

Trunk Flexion and Rotation – (Oblique Crunch)

• Agonists – Rectus Abdominis, External Oblique, Contralateral Internal oblique
• Synergists – Psoas, Ipsilateral Latissimus Dorsi, Multifidi, Rotatores (Including the Multifidi and Rotatores muscles as movers of the spine is debatable. There relative size, length, and proximity to the axis of rotation gives these muscle poor leverage for gross movement. However, this position is advantageous for proprioception and segmental stabilization)
• Antagonists - Opposing external and Internal oblique, Erector Spinae (Iliocostalis, Longissimus, Spinalis)
• Neutralizers - Quadratus Lumborum neutralizes lateral flexion force created by obliques
• Stabilizers – Intrinsic Stabilization Subsystem (Transverse Abdominis, Diaphragm, Pelvic Floor (levator ani, coccygeus), Multifidus, Rotatores, Interspinales, Intertransversarii)

Subsystem Stressed:

• Intrinsic Stabilization Sub-system - Transverse Abdominis, Diaphragm, Pelvic Floor (levator ani, coccygeus), Multifidus, Rotatores, Interspinales, Intertransversarii
• Anterior Oblique Sub-subsystem – External Obliques, Abdominal Fascia, Contralateral Anterior Adductors (Pectineus, Brevis and Adductor Longus)

Crunch (and oblique crunch) Progressions

1. Floor crunch with hands on knees
2. Floor crunch with hands across chest
3. Floor crunch with fingertips behind ears
4. Floor crunch with arms extended behind head
5. Floor crunch with rotation (oblique crunch) with hands on knees
6. Floor crunch with rotation (oblique crunch) with hands across chest
7. Floor crunch with rotation (oblique crunch) with fingertips behind ears
8. Resisted Floor crunch with and without rotation
9. Bosu crunch with hands on knees
10. Bosu crunch with hands across chest
11. Bosu crunch with fingertips behind ears
12. Bosu crunch with arms extended behind head
13. Bosu crunch with rotation (oblique crunch) with hands on knees
14. Bosu crunch with rotation (oblique crunch) with hands across chest
15. Bosu crunch with rotation (oblique crunch) with fingertips behind ears
16. Resisted Bosu crunch with and without rotation
17. Ball crunch with hands on knees
18. Ball crunch with hands across chest
19. Ball crunch with fingertips behind ears
20. Ball crunch with arms extended behind head
21. Ball crunch with rotation (oblique crunch) with hands on knees
22. Ball crunch with rotation (oblique crunch) with hands across chest
23. Ball crunch with rotation (oblique crunch) with fingertips behind ears
24. Resisted ball crunch with and without rotation

Ball Crunch and Progressions

Notes on Form:

The differences in muscle activity between a crunch and crunch with rotation does not vary enough to consider them separate exercises in a routine. Both exercises require deep intrinsic sub-system stabilization and dynamic strength from the rectus abdominis and obliques.

The largest challenge faced during dynamic core activity is finding exercise that does not continue to feed compensation patterns, especially those that may reinforce psoas dominance. Crunches can be great dynamic strength exercise for the core, but may contribute to psoas hyperactivity if special attention is not paid to form. 3 cues can greatly increase the effectiveness of your crunch type exercises, and decrease psoas activity.

First, do not hook the feet. Studies show hooking the feet or holding the feet down increases hip flexor activity.

Second - Glute engagement: Keeping the glutes contracted reciprocally inhibits the psoas. Squeeze your cheeks like your holding a dollar bill, pressing your feet through the floor.

Third, ensure TVA engagement is maintained through the entirety of the set. The most common misstep is the belly distending on the way up. Restart the movement pattern and subtly remind the participant to maintain the drawing-in maneuver through the full range of motion.

© 2011 Brent Brookbush

Questions, comments, and criticisms are welcomed and encouraged – Brent@b2cfitness.com