The “Plank” is a popular core strengthening exercise that is used in many rehab programs. If you ever have done rehab at Carone Chiropractic you have definitely seen this before. For those who have not, the plank is performed either on your hands (like a push-up) or on your forearms with your legs extended straight out. Your abdominal and glute muscles are contracted keeping your body in a straight line. Hold times vary depending upon strength of the person. This exercise is considered by most experts to be one of the top exercises for core strengthening and preventing of injuries such as lower back pain. But the exercise does not stop there.
Leg Up: While holding a plank, lift one foot off the ground hold it parallel with the rest of the body for 5 seconds. Lower and repeat with the other foot. Alternate for as long as you 
can hold the plank, squeezing the glutes and abdominals.
Mountain Climbers: Assume a plank position with hands in a push-up position. Maintaining a tight core, move your right foot towards your right hand in one smooth motion. Then return the right foot back to the starting position while moving the left foot to the left hand. 
Repeat as many reps as possible with out losing tightness in the core
Jumping Jacks: While in a plank position with hands in a push-up position or on forearms while holding the core tight, slide both legs apart in a quick smooth motion. Then move both legs back to the starting position. Repeat as many time as possible without losing form 