Fitness Ab Move: Jackknife Crunch
by Ted Bonham, TPI Certified Level 1 Instructor & Director of Fitness for Precision Instruction

The CoreA simple abdominal exercise for beginning and advanced fitness.Most want the “six pack” abdominal look, however most cannot achieve this because of age, body type, or various other reasons. A realistic approach and thought process should be, “How can I strengthen my core with what I already have?”

One of my favorite abdominal exercises is the “Jackknife Crunch”. This particular crunch is for the beginner and the advanced fitness person.

The most efficient way to perform this exercise to lie flat on a mat, legs pointed ninety degrees up toward the sky. A key part of this exercise is to have your lower back flat against the mat. I prefer this position rather than having an arch in the lower back. With the back flat against the mat, we are working just the abdominals and not stressing the lower back region. Place both hands together and reach up touching the toes as shown in the video. Remember to breathe, exhaling as you reach toward the toes; inhale returning to the start position. I like three sets of 15 repetitions for the beginner. For the advanced, 25 repetitions with weight, again for three sets. Start with low weight, five to eight pounds. Work towards weights of ten to fifteen pounds. Take a ten second break in between reps.

The core is an integral part of the golf and tennis movements supporting the athletic motion. A strong core not only supports the lower back, but provides power in the motion. Upper and lower body separation created by the twisting motion in the golf swing and tennis action is key to stability and power. This again, is supported by the core. Try this exercise and get started on more power in your sport. You never know, you may just get those “six pack” abs in the process.

Get your fitness evaluation today! Contact Ted Bonham at or you can schedule a fitness session by calling Precision Golf School at 336-510-4653.

Ted Bonham, IFPA,CTPI-1
Director of Fitness
Precision Golf School