Well, it depends on who you ask; however, everyone agrees that at least four muscles compose the inner core musculature. They are:
- the diaphragm (you use it for breathing, without it you'd be dead)
- multifidi (small muscles that run between your vertebrae, more developed on your low back)
- transversus abdominus (corset-like muscle that keeps your abdominal contents in place)
- the pelvic floor (you use them to stop the flow of urine, defecation and they are responsible for the pleasurable orgasmic contraction during sex)
- For a flatter, nicer-looking abdomen. Even without losing weight, you'd look trimmer. (ok, I said it. Let's move on because this is not about vanity... or is it?
- Better posture and balance
- Protection from potential back injury when done properly
- Maintenance of correct intra-abdominal pressure which play a role in the development of varicose veins and digestive dysfunction
- Better reaction time while shifting body weight in unstable terrain to increase sports performance
- More efficient transmission of force from the upper body to the lower body
- To bring your core strenght to at least baseline after abdominal surgery, back pain/injury and childbirth to avoid further injury to the area.
- After any lower extremity injury to avoid protective patterns of movement to become permanent so that you do not develop early degenerational changes
- To efficiently transfer the force produced by your lower extremities (legs) to your upper extremities (arms) and vice versa.
Stretch tight muscles: the erector spinae (responsible for bringing your torso to a straight position when bending and keeping your back straight during the day) and hip flexors are the ones to target. They shut off your core when exercising if they are tight. Your body adapts, but with these muscles taking the brunt of the work that should be performed by your core, you are an injury waiting to happen.
Balance work in any position: standing, sitting, on your side, using a BOSU or a physioball. Add instability to your routine. Do curls while standing on one leg, do leg abductions while doing a side plank, do resistance exercises while using the BOSU or physioball, add a pilates class to your schedule. Have a personal trainer look at your form while adding these variations to your routines. I have seen many people trying to add these in their routine only to strengthen a lot of compensatory problems that can lead to injury.
Rotational exercises using cable machines or medicine balls: a lot of sports require you to create torque using torso rotation: golf, tennis... even running or walking involve a bit of rotational movements. High and low woodchoppers and torso twists, lunges with a twist performed with a medicine ball are example of these. To a lesser extent, oblique crunches can actually help when performed correctly.
Kegel exercises: they specifically target your pelvic floor. Once you can do a set of 10 contractions held for 10 seconds with correct form. Also try adding pelvic floor contractions while you do your core and abdominal work at the gym or at home.
Breathing exercises: the diaphragm might be a muscle used for breathing, but it is the first muscle to fire when you move your extremities. Your transversus abdominus functions in forced expiration. Try Yoga, breathing centered meditation, pilates to strengthen these two muscles. Remember that when you take a breath your stomach protrudes; when you breathe out, your stomach goes in. If you don't breath that way, you will need to change your breathing patterns. There are specific exercises to help out with paradoxical breathing, but they are beyond the scope of this entry.
So, get to work! Ask your a personal trainer about the correct way to integrate these type of exercises into your routine.