FM 21-20 Circuit Training

Circuit training is an effective and efficient way to improve physical fitness. That's why the U.S. Army uses this mix of cardiovascular and strength training to train soldiers. The U.S. Army Field Manual addresses circuit training in FM 21-20.

The Basics

Circuit training involves performing a routine that brings you from workout station to workout station. There can be up to 20 stations, under Army guidelines. However, utilizing eight to 12 stations is more common. Training routines can be designed to emphasize strength building or muscular and cardiovascular endurance.

The Benefits

A circuit designed to build strength would include a number of weightlifting stations and would require soldiers to complete a certain number of repetitions. For example, a soldier would do eight to 12 repetitions of the leg press, leg raise, leg extension, leg curl, heel raise, bench press, seated row, military press, lat pulldown, shrug, triceps extension, biceps curl and incline sit-up. A soldier would do one or two rotations of this circuit, according to the "U.S. Army Fitness Training Handbook." A circuit designed to build muscle and cardio endurance would have soldiers perform tasks at stations for set amounts of time, such as 30 seconds to one minute, with the stations set farther apart to require more running. Soldiers do exercises such as ski jumps, running in place, mule kicks and push-ups.

The Science

Circuit training is more effective than endurance training alone for building fitness, according to A. Paoli, lead author for a 2010 study published in the "Journal of Sports Medicine and Physical Fitness." Also, high-intensity circuit training is significantly more effective than low-intensity training when it comes to improving body composition and strength, Paoli notes. High-intensity training in general calls for little or no rest between stations and involves working at your maximum potential, or pushing to failure.

How You Can Use It

If you want to utilize a 20-minute circuit training routine to mix cardio and muscular endurance, Military.com recommends one that you perform without rest between stations. This routine consists of one minute on each of the following exercises: bench press, squats and pull-ups. Then jog or bike for three minutes. Next is one minute doing military presses, one minute of lunges on each leg and a minute of biceps curls followed by another three minutes of cardio. Do triceps extensions, leg extensions and leg curls each for a minute, then sit-ups and crunches for two minutes each. Follow your workout with a stretch, and warm up before you begin. This workout is recommended by former Navy SEAL Stew Smith, who is certified as a strength and conditioning specialist by the National Strength and Conditioning Association.