No points scored if you've guessed we're talking about 5 (with a good bit of 4 thrown in as it's pretty essential to your function.)
A lot of the time when people talk about the 'core' or core exercises, they mean abs and mostly crunches. When I talk about the core, I mean everything from your ribs to pelvis. If you've heard me talk about the pelvic floor and how it doesn't really work to focus on it as a muscle in isolation, then you'll not be hugely surprised if I say there's not much point in just focussing on your abs.
Contexts to explore: What are you aiming to do? What goes on around the transverse abdominus?
Breathing is an instrinsic part of your core. Although you might initally, be thinking - 'nah, that's my ribs' let me carry on... You might have tried 'belly breathing' in yoga class or as part of a relaxation, or maybe you've had the unfortunate experience of combining a nasty cough with a sore back? If so, you will know that your breathing affects more than just your upper body. When you breathe, each breath alters the amount of pressure in your abdomen (or 'core').
There was a big buzz about core strength a while back. And yes, it is important to have some strength in your abdominals, but more important to have a reflexive core - that means that your muscles work well through your body. It's a more holistic approach where you'd consider how stong your back is (as it's also part of the trunk of your body) and the relationship with breathing above and how your 'core' functions in movements below. i.e. you may be doing sit ups or crunches intending to strngthen your core, but in fact be adding pressure that does nothing to help problems down below. Can you see where I'm heading with this?
Another important area to be able to move freely and respond well to movements above and below is your pelvis. Breathing well, moving well and looking at alignment with your 'core' and how you sit, stand and walk can all benefit your pelvic health. The pelvic basin regulates forces from above and below and is vital for digestive health, sexual function, conception, birth and comfort in movement.
legs bums tums
It's good, but it's not right. All in one sentence, but not necessarily joined up.
Looking at body parts in isolation doesn't always lead to optimal health. But how you sit and how you use your legs when you walk are all parts of this bigger core picture. Do you work your glutes on a daily basis? I don't mean by doing a daily workout here, I'm wondering if they are involved in how you push off when you walk, or how often you use them to get up from sitting?
what are you trying to do?
The other factor here, is what you're aiming to do. Some people look at core srtength as a catch all for everything from easing back pain to postnatal recovery, via getting wedding-ready. As we've already seen, your core relates to so many vital functions in your amazing body. My starting point is always to come to the foundations of how you move through everyday life, rather than just how you fit a particular pair of jeans. What might the root of your back or pelvic pain be, rather than going straight to crucnches to add strength.