The plank, according to many experts, is by far one of the best exercises for strengthening the core. A staple exercise of yoga sun salutations and Pilates-based classes, the plank has been around for a long time and it’s not going away anytime soon.Planks, in a way, are the new sit-ups. Traditional sit-ups strengthen your abdominal muscles, but you won’t get very far without a strong base. Your midsection needs to also be strong to stabilize your body, as stabilization enables you to tap into strength and power in other parts of the body. Planks recruit so much more of the body to perform the movement, and with so many different variations not only do the muscles of the core get a workout, but this staple move also strengthens your hips, shoulders and arms in the process.For those of you who have mastered the four basic planks—front plank, side plank, reverse plank and high plank—instead of trying to beat the current world record of holding a plank for 3 hours, 7 minutes and 15 seconds, try these four variations to squash boredom and add some serious new challenge to this tried-and-true move.Forearm “Pass the Plate” PlankInstead of the traditional forearm plank, try adding upper-body movement and load:Using 5-10 lb barbell plates or 3-10 lb dumbbells, plhealthsite three to five weights to the right side of your body. Position yourself in a forearm front plank. Reach with your right hand, grab a weight and transfer it to the other side. Continue to transfer all the weights before releasing the plank. Rest for two seconds, lift back up into the forearm plank and transfer the weights from left to right. Perform a total of three sets (one set is right-to-left, then left-to-right). StabilityFor added stability, drop to the knees or stay on the toes and widen the stance. To challenge stability, stay up on the toes and keep the legs close together. Rolling Side Forearm PlankInstead of the traditional side plank, try adding travel:Begin in a side plank to the right, with the right leg and arm lifted. Hold this position for three seconds. Roll onto your back and move into side plank to the left with your left leg and left arm lifted. Reverse and move back into side plank to the right and hold this position for three seconds. Perform a total of eight side planks on the right and eight on the left. StabilityFor added stability, roll to side plank and then lift the leg and arm. To challenge stability, perform side plank with both legs straight. Reverse Table Top Dumbbell Arm ReachesInstead of the traditional reverse plank, try adding upper-body movement and load:Position the body into a reverse plank, keeping the knees bent and feet flat on the floor as you hold 5-10 lb dumbbells. Alternate lifting the dumbbells to the ceiling. Perform two sets of 10 repetitions, alternating sides. StabilityFor added stability, perform this exercise without the dumbbells. To challenge stability, perform this exercise with straight legs. Full Plank With Ankle TouchesInstead of the traditional full high plank, try adding leg movements:Position the body in a high push-up position. Lead with the inner thigh and touch the left hand to the right ankle. Switch sides, touching the right hand to the left ankle. Complete a total of eight repetitions on each side. StabilityFor added stability, keep both hands on the ground and move just the legs. To challenge stability, gradually pick up the phealthsite of the leg movements. For more ideas on how to upgrade your planks, check out healthsite Master Trainer Jonathan Ross’ favorite plank exercise variations.