Strengthening your core is important for just about everything you do. Most movements, whether they’re fitness activities or just every day life, originate from your core. Your core muscles work to stabilize your body and help produce power for movements of your limbs.
Your core involves all the muscles of your trunk not just your abs and low back like most people think. Doing a few sets of sit ups and bird – dogs is not going to cut it if you truly want to strengthen your core.
Your core is basically everything but your arms and legs. It includes your glutes, hips, abs, low back, upper back and chest. Your upper back and chest are less involved in certain core movements but are still connected to the whole core chain.
Here are some great core exercises that can be done with minimal or no equipment. And not one sit up in the bunch!
Planks (the exercise you love to hate!)

Planks
Side planks (a slightly more challenging variation)

Side Planks
Plank with leg lift (alternate leg lifts for up to 10 reps each)

Plank with leg lift
Seated leg lifts (I’m horribly inflexible so this is a tough one for me because my hamstrings are so tight!)

Seated Leg Lifts
Bridge

Bridge
Back extensions (these can be done on a machine in a gym as well)