Pushup Plank With Alternating Knees
This exercise will improve core stability.
Go into the top of a pushup. Brace your abs and squeeze your butt to form a straight line from the top of your head to your ankles. Without moving your body, bring one knee into your chest. Do not round your back. Return the leg to the starting position and switch sides. Alternate for 60 seconds and repeat for three sets.