Core Gym Exercises

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In the gym, there are many ways you can work your body core for strength, stability and definition. To get the best results, you will need to work in various positions to target all of the core muscles. For example, you can use a stability ball or a BOSU ball or a medicine ball.

Reverse Sit-ups

A basic core exercise in the gym includes reverse sit-ups. Sit on a mat with your knees slightly bent and feet apart. Cross your hands over you chest, lean back and exhale. Return to an upright position on the inhale. Repeat 10 to 15 times. Lighter modifications of this exercise include placing your hand behind your thighs rather than crossing them at the chest or placing your hands on the floor behind you for support. More advanced variation include holding a weight or resistance all and pushing it forward as you curl back.

Stability Ball Crunch

Find a stability ball that is the correct size for you by sitting on the ball and making sure your hips are just slightly higher than your knees when seated. To get into the starting position for a stability ball crunch, start seated and then walk forward with your feet as you lean back into the ball. Stop when your lower back is supported on top of the ball, with your head, neck and shoulders suspended off the back of the ball. Your upper body should be parallel to the floor and not dropping down behind the ball in your start position. Make a fist with both hands and place them under your chin. Using an exhale breath, slowly slide your ribcage toward your hip bones and curl your upper body upward into a crunch position. The ball should not move as you curl up or as you release back to the starting position. Avoid pushing into your legs, and be careful to release your upper body only to the parallel starting position.


A downward or front plank is a basic core exercise that doesn't require any equipment. Place your hands on the floor and walk your feet back until your back and legs are in alignment -- just as if you were going to do military-style push-ups. Keep your shoulders lined up directly over your hands. Hold for five, 10 or 15 seconds. As you build up strength, you can advance to a plank using the BOSU. The BOSU looks like half of a stability ball on one side with a flat black platform on the other side. Most gyms will have a BOSU stored in the same area as the stability balls and mats. Using a BOSU with the rounded side down, grip each side of the black platform, placing your thumbs near the indented handled area. Step your feet back until your body is in a plank position. Your body should be parallel to the floor, with your abdominals pulling in and your knees straight. Look just slightly in front of your hands to maintain alignment, and work at keeping the BOSU steady as you hold your plank for one minute at a time.

Medicine Ball V-Sit

Medicine balls will typically be found in the gym near the mats and stability balls as well. Medicine balls are often stored in a tiered rack with the larger balls on the bottom, and the smaller balls near the top. The larger the medicine ball, the heavier it will be. Choose a lighter ball the first few times you perform this exercise, then choose a heavier one after you are more familiar with the movement. Start seated on a mat, with your legs in front of you and knees slightly bent. Hold the medicine ball near your chest, then lean back from your hips keeping your back straight. Your body should look like a "V", with your shoulder blades pulling back to help keep you tall through the spine. Hold this position for a minute, take a short break, and repeat. For more challenge using the obliques, after you are in the v-sit position, rotate the medicine ball side to side for 15 to 20 repetitions per side.