To chisel your abs and strengthen your core, add some dumbbells to your core workout. Adding some weight forces the fibers in ab muscles to activate more fully, making each rep more effective. This V-sit variation is a stability exercise, where you train your torso to remain still as your arms move away from your center. It's a must-do move and great for endurance athletes.

Related: Standing Ab Exercises With Weights [1]

Start with a set of five-pound dumbbells and work toward using eight-pounders.

• Begin sitting with your heels planted about two feet from your butt, holding the weights at chest level with a slight bend in your elbows. Keeping your spine straight, lean back a few inches, pulling your abs toward your spine. Do not let your lower back round.
• Keeping the left arm still and torso stable, exhale as you open your right arm to the side, making sure the weight doesn't go beyond your shoulder. Looking forward, you should be able to see your right hand in your peripheral vision.
• Inhale as you bring your right arm back to center to complete one rep. Complete 10 reps with the right arm, using every exhale to deepen your abdominal connection by actively pulling your navel to your spine.
• Ten reps on each side completes a set, and we recommend doing at least two sets.

Related: Best Ab Exercises Using Weights [2]