You do not need to get on the floor to work your core! Working your core will not spot reduce belly fat, but having a strong core should be a high priority in your training. All movements stem from the core, and strength in the core will make you stronger overall. Having a strong core will also reduce your risk of being injured during physical activity. There are many ways you can incorporate core into your routines without getting down on the floor for the traditional sit ups and crunches. The theme of core training is neutral spine stability through all planes of motion.
Single limb exercises: Any time you remove a limb of support such as doing an exercise with a single arm or leg, your core is going to work harder to keep you stabile. All forces traverse the core and the greater the amount of instability of an exercise, the greater the demand placed on the core. Examples: 3 point plank row, single leg RDL, Single arm dumbbell press, etc.
Rotary Stability: Resisting rotation is an extremely effective way to target the oblique abdominal muscles. Resisting rotation is required for any single limbed exercise as rotation is one of the many degrees of freedom in which a joint can move when forces are applied unilaterally. Good form on many exercises requires the control of rotary forces, also known as rotary stability.
Example: Try the Paloff press- Stand with feet hip width apart and completely perpendicular to a function trainer cable machine. Place 2 hands on a single cable handle and pull handle to the midline of your body. From there press the cable straight out and hold directly in the midline of your body as the cable tries to rotate you to one side. Hold for 20-40 seconds and switch sides and repeat.
Leg Lifts: The hip flexors are one of the more complex muscle groups of the core. They are often tight which calls for foam rolling and stretching. That will release them of some tension on the muscle, which instantly strengthens them before you even start exercising. Leg lifts are great for the hip flexors, but many people do not do them correctly. Remember neutral spine stability is the theme of core training. You must keep your back (especially lower back) flat to the floor or pad while performing the lifts. On any leg lift your superficial abs should be super tense. This will prevent any unwanted spinal extension during the lift. If you find that when you do leg lifts your lower back keeps rising up, then try doing one leg at a time or shorten the lever by bending at the knee.
Examples: Alternating leg lift, hanging leg lift
Planks: It seems that every minute there is a new plank variation to try. The plank is one of the safest and easiest ways to strengthen the core. The plank is all about creating a lot of tension on the abdominal and glute muscles to lock the spine and pelvis into place. It also forces you to breathe while bracing your core. Bracing and breathing is an extremely valuable skill in any form of exercise. Planks can be as basic as just holding push up position, and can be progresses into moving, single limbed, and/or unstable planks.
Examples: Single arm plank, Single leg side plank, abdominal roll outs.