Bring yourself to the ground and enter a forearm plank position with your elbows directly under your shoulders and your legs extended directly behind you. Place a weight an arm's length distance in front of you. This is your start position. Maintaining a braced core and neutral spine, lift your left hand on the floor and reach forward to tap the weight. Return the left hand back to the floor and repeat the same movement with your right hand. Perform this alternating movement for the required number of reps (or time).