The crunch is a vastly overrated ab exercise.

Crunches shorten the rectus abdominis (“six pack”) muscles, and don’t strengthen the entire abdominal region.

A bodybuilder doing partial-range biceps curls might be laughed out of the gym, but it’s perfectly acceptable to do partial-range sit-ups.

Partial-range movements are usually restricted for pre-fatiguing a muscle or to work on a weak spot in a full-range motion exercise by inducing a “functional isometric contraction” at a specific joint angle.

That’s why a quality power rack in a gym always has two sets of pins.

San Diego State University (in a study led by Peter Francis, Ph.D.) rated ab exercises on EMG machines.

From most effective to least effective for the rectus abdominus, the ratings were …

248 – elbow-to-opposite-knee “bicycles”

212 – hanging knee raises

139 – crunches on an exercise ball

129 – vertical leg crunches

127 – torso-track machine exercises

119 – long-arm crunches

109 – reverse crunches

107 – crunches with a heel push

105 – ab roller exercises

100 – bridges with weight on the elbows

100 – traditional crunches

092 – exercise tubing pulls

021 – ab rocker exercises

From most effective to least effective for the abdominal oblique muscles, the ratings were …

310 – hanging knee raises

290 – elbow-to-opposite-knee “bicycles”

240 – reverse crunches

230 – bridges with weight on the elbows

216 – vertical-leg crunches

147 – crunches on an exercise ball

145 – torso-track machine exercises

126 – crunches with a heel push

118 – long-arm crunches

101 – ab roller exercises

100 – traditional crunches

077 – exercise tubing pulls

074 – ab rocker

My belief in “all-or-nothing” muscle contraction was shattered when I saw a belly-dancer place eight quarters on her abdomen and roll any quarter or combination of quarters up and down her midsection on request.

She also used her talented ab muscles to fold dollar bills into halves, quarters, and eighths.

Remember – and if you’re a regular reader of Atom’s Blog, you already know this – the primary cause of central obesity (belly fat) is GASEOUS PRESSURIZATION, mostly due to carbon dioxide.

I’ve been telling people about carbon dioxide’s role in weight gain since the 1970s, and scientists are just starting to get a clue about it this year with headlines like …

“Scientists Discover Link Between Carbon Dioxide and Obesity”

“High CO2 Levels Are Making People Fat, Says New Study”

“Blame the Smog For Your Weight Gain”

“Could Air Pollution Be Making Us Fat?”

“Does Carbonated Water Cause Weight Gain?”

Etc.