Gen. James Conway, commandant of the Marine Corps, didn't say those exact words when he issued a shape-up-or-ship-out message to all Marines, but he might as well have.

CHARLIE NEUMAN / Union-Tribune Lance Cpl. Mark Ashley carried Lance Cpl. Brendon Law as part of the obstacle course portion of yesterday's combat fitness test at Camp Pendleton.

The nation's top Marine has created a rigorous fitness test to gauge combat readiness and has ordered strict enforcement of body-fat standards that he said have become lax in recent years.

“Tendencies toward increased weight have become a dangerous trend over the last decade in our American society. But Marines are different,” Conway wrote in an Aug. 8 message.

About 100 Camp Pendleton Marines got their first look at the new test during a demonstration yesterday. They repeatedly lifted 30-pound ammunition boxes above their heads, crawled on their bellies through a mock battlefield, lobbed fake grenades and, of course, did push-ups.

“Every single part of my body is hurting. It's a lot harder than I thought,” Lance Cpl. Jesus Corella of Nogales, Ariz., said after finishing the obstacle course portion of the test in less than three minutes.

It took nearly 10 minutes for him to catch his breath.

Starting Oct. 1, the nation's 190,000 active-duty Marines must pass the combat fitness test twice each year. The regular physical fitness test will continue to be given at least twice a year.

Another major change by Conway is his mandate to separate tests that measure physical abilities from requirements for personal appearance. Marines who post excellent scores on physical tests will no longer be allowed to exceed the Corps' body-fat standards by a few pounds.

Male Marines ages 17 to 26 will be allowed a maximum of 18 percent body fat, while the figure for young women is 26 percent. (The percentages are slightly higher for older Marines.) In the past, those with strong results on the physical fitness test were allowed to slightly exceed those standards.

Conway granted one exception: Officers can pass Marines who don't fulfill the body-fat requirement if they believe those troops still look trim in uniform.

Conway said Marines with excess body fat threaten combat efficiency and effectiveness “and, unfortunately, (are) a clear indicator of some commanders' failure to enforce standards.”

Out-of-shape Marines will be warned informally and have 120 days to get lean. If they don't, they will be enrolled in the more formalized Body Composition program.

If Marines fail to make progress, they likely would not be promoted and could be discharged.

That's the way it should be, some former Marines said.

“They know exactly what they're there for. . . . This is not the Vienna Boys' Choir. If they wanted something less or an easier way to do it, they could sign up for something else,” said retired Lt. Col. George Murray of Carlsbad.

Physical fitness is a responsibility that every Marine should take seriously, said retired Brig. Gen. David Brahms of Carlsbad, a lawyer who specializes in representing military defendants. Still, he sees nothing but Marines in tip-top shape wherever he goes.

“The bottom line is that when (Conway) issues this program, he's saying there is a problem in the Marine Corps. Personal pride, striving for excellence – apparently they aren't doing it. That's sad,” Brahms said.

Other veterans said Marines need to be ready for the rigors of combat in Afghanistan and Iraq. Many troops wear form-fitting body armor, Kevlar helmets and other equipment that previous generations didn't lug around.

The combat fitness test consists of three events.

Marines first run 880 yards – two lengths of an Olympic-sized racetrack – while wearing boots and camouflage utilities. Men ages 17 to 26 must complete the run in three minutes, 48 seconds. Women in the same age category are allowed an additional 46 seconds.

Second, they need to lift a 30-pound ammunition box from below their chin to above their head as many times as possible in two minutes. Men must complete 45 reps, while women must do 20.

The final event is an obstacle course reminiscent of any boot camp scene ever put on film: crawling, dragging fellow Marines, running while holding 30-pound cans, lobbing fake grenades and doing push-ups.

All of the participants yesterday exceeded the requirements for each portion of the test. One Marine lifted the ammunition box more than 100 times, and three finished the obstacle course in less than three minutes.

Several said the combat fitness test was far more difficult than the physical fitness test, which consists of pull-ups, crunches and running.

Col. Brian McGuire of the Marine Corps' Training and Education Command in Quantico, Va., which developed the combat fitness test, visited Camp Pendleton yesterday to explain the benchmarks.

He said the goal is to gauge and improve the “short bursts” of energy that Marines need in combat situations.

Without giving specifics, McGuire acknowledged there is a “growing” number of overweight Marines. But he said the latest fitness and appearance requirements are based on Conway's observations instead of a particular study or set of statistics.

After watching yesterday's demonstration, Lance Cpl. Haley Faris of Atlanta said she thinks the combat fitness test will force her and many other Marines to focus more on all-around conditioning.

“It has been kind of a problem seeing overweight Marines lately,” Faris said.

This isn't the first time the Marine Corps has overhauled its physical fitness requirements.

In 2002, after three years of study, it permitted female Marines to be a bit heavier than the previous standard and made the body-fat exception for service members with high test scores.

Two years ago, commanders were authorized to exempt Marines from complying with the body-fat scale until they returned from their combat tours in Iraq.

The Marine Corps continually adjusts its programs and thresholds to maximize the potential of its force, said retired Master Sgt. Vic Ditchkoff, president of the United States Marine Corps Drill Instructors Association.

Ditchkoff, who trained more than his fair share of Marines during his 26-year career, views the combat fitness test and renewed emphasis on body-fat standards as an attempt to “nip it in the bud” before too many Marines get comfortable with an expanded waistline.

In the end, though, he said it's not like Marines are going to turn into couch potatoes.

“I don't think there has ever been a time when our physical fitness program hasn't challenged every Marine,” Ditchkoff said.

Craig Gustafson: (619) 293-1399; craig.gustafson@uniontrib.com