Your core, which is loosely defined as your body minus arms and legs, consists mainly of the spine and hips. It’s the basis of movement, and keeping it healthy and supported is so important.

We have two major abdominal muscles that work as a team, like Batman and Robin, to protect our core from harm: the transverse abdominus (which stabilizes the spine) and rectus abdominus, think six pack, (which moves the spine). The transverse provides the foundation while the rectus actually does the moving during physical activity. The stronger the foundation, the more efficient and successful the movements.

Most of us tend to have a strong rectus abdominus but weak transverse abdominus, mainly because we neglect to train it. When the transverse is weak, we lack core support, thus placing stress on the spine, often leading to lower back pain and injury. You’ve probably seen the guy or gal doing squats or pushups with an excessively arched lower back.

My philosophy on core training consists of training our support muscles first. This will lead to more productive, pain-free workouts. Due to its deep positioning within the core, the transverse responds only to isometric (tension without muscle contraction) exercises, that last 20-30 seconds. You’ve probably heard of plank or bridge. These exercises are key, as “crunches” don’t have the same effect.

Below are a few of my favorite core exercises that will strengthen both muscle layers. Some of these are very challenging, so let your body progress properly and safely.

Transverse abdominus:

Floor plank (beginner) – Start out face down on elbows and feet, both shoulder width apart. Keep your back flat, chin tucked and buttocks squeezed. Hold this stance as long as possible without compromising form.

Feet on ball plank (intermediate) – Start out in a pushup stance with hands on floor and feet on top of a stability ball. Maintain the same posture as the floor plank. Hold this stance as long as possible without compromising form.

Stability ball and medicine ball combo plank (advanced) – Maintain the same posture as the last exercise. Place your hands on top of an 8-10 pound medicine ball. If you can hold this plank longer than 40 second consider yourself a rock star!

Rectus abdominus:

Floor crunch (beginner) – Lay flat on your back with feet flat and knees bent. Place your hands behind you head. Keep your belly button pushed into your spine. Lift your head, neck and shoulders off the floor to a 45 degree angle (just a few inches from the floor). Hold for a one-count at the top of your crunch. Repeat without compromising form.

Jack knives (intermediate) – Lay on your back with your arms above your head. Lift arms and legs simultaneously from the floor, allowing them to touch above the body’s waist line. Repeat without compromising form.

Toe to bar touches with pull-up (advanced) – Hang from a pullup bar. Perform one pullup to start then return to the hanging position. Rotate your torso up toward the bar until feet tap. If you can complete more than five reps, give yourself a huge pat on the back.

Try this weekly challenge: 50 crunches, 400 meter run on treadmill and 60 seconds of ‘feet on ball’ plank. Complete three sets, circuit fashion.