01 November 2020

The Abdominal Crunch - Working Towards a Flat, Chiseled Stomach



By Dr. Jim Bell

Before I get into the abdominal crunch, it is important for you to know that you can do crunches for 16 hours/day; 7 days/week and you will not have a "six pack" or win an ab contest until you get the fat off your waist line. Reducing your percentage of body fat requires a disciplined approach to a simple formula. If you burn more calories than you consume you will lose fat. You burn calories through physical activity and you consume calories through eating and drinking. The typical person greatly over estimates the amount of calories they expend and greatly underestimates the amount of calories they consume.

The crunch is the most effective abdominal exercise with the lowest amount of risk. Performed correctly you can negate virtually all risk of injury. The following describes the most safe and effective way to perform crunches.

To get in position: from standing position squat down; place your hands on the floor in front of your knees and walk your hands forward until you are on "all fours" (hands and knees resting on floor or mat, back parallel to the ground).


Bend your arms, lowering your shoulders to the floor and roll onto your back.


Feet should be flat on the floor, shoulder width apart with the knees bent.


Fingers should be interlaced behind the head for support. Do not pull forward on the head while contracting the abdominals. Excessive pulling of the hands on the head can cause damage to the cervical & thoracic discs, ligaments and muscles. The hands form a platform to rest the head. If you are deconditioned, your neck muscles will fatigue faster than your abdominals.


Contract the abdominals to "curl" the head and shoulders off the floor. Pretend a string is attached to your nose pulling your face upward toward the ceiling. This technique will prevent the chin from coming to your chest. (If all else fails, put a tennis ball under your chin to protect the neck).


Keep the lower back on the floor and pull the stomach inward while contracting. This will activate the transverse abdominus. Always exhale during the concentric contraction and use a 2 second timing if you are a beginner (gradually extend contraction time to 4, 6, 8, and 10 seconds; advanced trainers may want to try 10 second concentric; 10 second isometric contraction at full flexion and 10 second eccentric). Inhale during the eccentric contraction and use a 4 second timing if you are a beginner (gradually extend contraction time to 6, 8 and 10 seconds).


Variations of the crunch include:


  • Twisting Crunch: with a twisting motion toward the outside knee
  • Legs Elevated Crunch: bent-knee or straight-legged with legs pointing toward the ceiling.
  • Legs Elevated Straddle: legs straight in straddle position
  • Crunches on a Stability Ball


In all the exercises described above never have the feet held down since this causes a flexor synergy that will decrease the contraction of the abdominals and increase the recruitment of the hip flexors. Allowing the back to leave the ground as in the old-fashioned "sit-up" will have a similar effect and is not recommended.


When you complete the desired number of sets (recommend beginners start with 1 set of 15 repetitions gradually increasing number of sets; remember Frequency, Intensity, Time and Type from your PFT Course), it's time to return to a standing position. The safest way to accomplish this is reverse the process you began with: roll over to one side until you are back on your hands and knees. Walk your hands back toward your feet until you return to squat position and stand up.


Yoga and Pilates include many exercises that strengthen the core and trim the waistline. If you are a personal trianer looking to expand your expertise to include yoga and pilates, check out our specialized fitness certifications: Yoga Instructor
and Pilates Instructor

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