All the time, clients ask me to help them work on their core. When they say this, they're actually thinking about targeted ab exercises—things like crunches, for instance. But what people often don’t realize is that they can work their core in basically every movement they do—both in and outside of the gym. Your core is both your traditional ab muscles and the complex of deeper muscles in the abdomen, back, and hip. It is what gives the body lift, and keeps us from slumping like a sack of potatoes. Simply keeping your body upright when sitting down or walking around is already working your core. Take that idea to its logical conclusions—i.e., holding yourself upright through patterns of movement is core work—and you will have a template for adding core work to everything you do, without ever having to get rid of your favorite exercises.
Your usual workouts can be modified to become core workouts simply by doing your exercises on one side at a time. By throwing your body slightly out of balance, a unilateral exercise (only one leg or arm working at a time) will force your core to compensate for the instability in your movement. Those adjustments, both large and small, that your core has to make to keep you stable as you lift in a lopsided way will give you unexpectedly significant strength gains. And that, in turn, will let you lift more.
The best thing about unilateral exercises is that they are the exercises you know and love—just executed with one side at a time. You don't need to learn anything special; just do a dumbbell chest press, for instance, with one arm at a time, alternating arms for each repetition (the easier version), or doing an entire set with one arm before moving to the other (harder because it allows no rest between reps on the lifting arm, and gives you more opportunity to become unbalanced). Since this is a familiar exercise, you should be able to be very conscious of the small adjustments you need to make in your body to maintain a centered position. That is the benefit of doing unilateral work in familiar exercises: feeling the difference.
That said, you may find that you master the single-sided exercise. If so, do there is another frontier: do the single sided exercise standing on one leg, or standing on a BOSU, or sitting on a stability ball (depending on the type of exercise). This will add a further destabilizing element, and an additional core challenge.
Here are some examples of unilateral movements:
Dumbbell Chest Press: Lie on your back on a flat bench with a dumbbell in one hand, elbows bent and hands close to your chest, palms toward your feet. Using only one dumbbell, perform a chest press by pushing the weight straight up toward the ceiling. You can use your other arm as a “phantom” arm and complete the movement so it feels a bit more normal. You may want to start with a lighter weight, as it takes a bit of getting used to and you don’t want to fall off the bench. Keep your back flat on the bench—and feel your core help you to push the weight. Your body will feel lopsided, so you need to keep your core activated so that you are in proper alignment. If the movement is easy, try lifting the opposite leg off the ground.
Dumbbell Shoulder Press: Stand with both feet about hip width apart and hold a dumbbell at shoulder level, palms facing inward. Perform a dumbbell press, pushing the dumbbell straight up into the air. It is important on this exercise to keep your core tight, so that you don’t lean to one side. You want to stand up tall as you press the dumbbell up. Again go a bit lighter than you normally would until you are comfortable with the movement. If it is easy, try standing on the opposite leg, or standing on the blue side of a BOSU.
Dumbbell Lateral Raises: Keep feet hip width apart and hold your arms down at your sides, palms in, with a dumbbell in one hand. Again, stand up tall and do a lateral raise, lifting the weighted arm straight out to the side, keeping the elbow straight but not locked. Your body will have a tendency to lean to one side, so you need to keep your abs “on” to keep you upright. If it is easy, try standing on the opposite leg, or standing on the blue side of a BOSU.
Dumbbell Curls: Stand with feet hip width apart, and a dumbbell in one hand. Perform a curl with the weighted arm, keeping the upper arm close to your body and being careful not to lean over the "heave" the weight. If easy, stand on one leg or on the BOSU.
The above are just some examples. You can try unilateral movements with just about any exercise. I definitely recommend trying some out this will help you to get out of your comfort zone, and to strengthen your core in ways that just doing crunches can’t!
About Mike Clausen: Clausen is the founder and co-owner of DIAKADI Body training gym, voted best personal training gym in San Francisco by CitySearch in 2006. He has been actively involved in sports and weightlifting since high school, and continues to use that knowledge when training his clients. Clausen is both A.C.E. and N.A.S.M. certified and has been training clients professionally for six years. He enjoys making his clients stronger, both physically and mentally, giving them the tools to create an efficient body and to do things they thought were not possible.