You don't have to sign up for boot camp to train like the U.S. military. Abdominal workout routines developed by the U.S. Army can help soldiers and civilians alike develop a powerful core.
Benefits of a Strong Core
The core is the foundation for powerful movements and physically demanding activities required by entry into the military. Having a strong core can help reduce injuries from activities such as weightlifting and climbing, as well as high-intensity activities like sprinting or football.
Additionally, a strong core is a good indicator of overall fitness; these exercises develop strength in the muscle groups in your arms and legs, not just in your lower abdomen.
4 for the Core
The U.S. Military provides their Pocket Physical Training Guide to new recruits. This extensive document provides detailed instructions for a workout that covers all aspects of physical fitness, including an abdominal workout designed to give you a strong core.
This workout, titled "4 for the Core," includes four advanced exercises that specifically target your abs, lower back, and pelvis. These exercises are designed specifically to limit strain on your back by using static positions that tighten and flex your abdominals.
Try completing these exercises in a cycle, with about 30 seconds or eight repetitions given to each exercise, for an intense workout routine that pushes your core to the limit.
1. The Bent-Leg Raise
The first exercise in "4 for the Core" is the Bent-Leg Raise. For this exercise, lie on your back in a sit-up position, with your hands flat on the floor. Next, tense your abdominals, and raise your feet and legs off the floor until your bent legs form a 90-degree angle, with your calves parallel to the floor.
The U.S. Army recommends imagining you're pulling your navel toward your spine, as if preparing for a blow to the stomach. Once you've raised your bent legs as far as they'll go, return to the starting position and repeat for one minute. The Bent-Leg Raise is a good replacement for the sit-up, as it puts less stress on your spine.
2. The Side Bridge
The next exercise is the Side Bridge. Start by lying on your side, with your upper body propped up on your elbow, forearm and fist. Next, cross your legs, placing your bottom leg over your top leg with your feet together.
Lift your hips and legs off the ground, supporting yourself with just your arm and feet, and hold the position for one full minute, or as long as possible. Switch sides after one minute.
3. The Back Bridge
For the Back Bridge, lie on your back as you did for the Bent-Leg Raise, with your palms laid flat on the floor and your arms at a 45-degree angle from your body. Next, contract your abdominals and raise your hips off the ground until your torso and thighs form a straight line.
Then, straighten one leg without allowing your body to sag or rotate. Hold for five seconds, and switch legs. Repeat for one minute, or as long as possible. This workout engages the lower abdomen, and engages several muscles to maintain balance as you raise and lower your hips.
4. The Quadraplex
The final exercise in "4 for the Core" is the Quadraplex. Start on your hands and knees, with your back parallel to the floor. Next, perform the same abdominal contraction you used in the Bent-Leg Raise and the Back Bridge, and straighten your left leg and right arm, keeping your back straight and level.
Hold this position for five seconds, and then switch to the right leg and left arm. Repeat for one minute, taking extra care to keep your body still while alternating your arms and legs. Switching back and forth requires coordination and core strength, making this one of the most challenging exercises in 4 for the Core.
If you're having trouble completing any of these exercises, start with a simple front plank and slowly build up your strength over several weeks until you can begin incorporating the more advanced exercises comfortably.