One move, six variations. Additionally, you don't want to work your abs every day. It's a mistake I would see all the time in the gym, but you wouldn't train your back or chest everyday, so treat your abs the same way. You have to give the muscles time to rest and rebuild so three times a week is more than sufficient to work your abs.
Keep this in mind when planking:
Start in a traditional plank position, hips tucked under strong, wrists directly under elbows directly under shoulders. Don't let your butt lift up or your tummy sag down. Then you'll switch to ...
Your forearms and elbows, before returning to your start position. I generally do about 15 switches, up and down counting as one. Hold for about 5 seconds before each switch.
Rest for about 30-45 seconds, then switch to a side plank. You can also do this move on your hand as opposed to forearm to make the move more difficult. Same alignment as far as having your elbow lined up under your shoulder, pressing strong into the ground and being sure to keep your hip lifted, not sagging towards the ground. You can add a leg lift on your top leg to up the ante. Keep that foot flexed and lift straight up and lower slowly and repeat 12 times. Once you've held this pose for about 30 seconds to one minute, switch to your other side.
This time, you're going to flip over and take that tummy to the ceiling. Keep your hands under elbows under shoulders, butt and hips tucked in tight and legs straight and tight. To increase the difficulty, you can add a leg lift here as well, toes pointed, lifting towards the ceiling, returning to start position and repeating about 12 times before switching to the other leg.
Side Plank Reaches:
Same position as the traditional side plank, this time, you're adding in that arm raise, then reach under your waist and back to the top. Repeat this move 10-12 times before switching to the other side and doing the same thing.
Plank with Knee Drops:
You'll being with this move by assuming a traditional plank position, then slow and controlled, lower your knees to tap the ground before returning to the start position. Repeat 15 times.
Plank with a Row:
For this move, you'll need your dumbbells. Assume a plank position, but with you hands around your dumbbells. You're going to alternate lifting your dumbbell up, driving your elbow to the ceiling and keeping your arm tight by your side. Return to start position, and repeat on the other side. 12-16 reps here depending on the weight you're using.
Cycle through each of these moves three times in circuit format. In other words, do one full set of each of these moves, then move to the next and so on. Once you get to the end, start back with the first move and go through each one again. What I love about planks is that they are core focused, but an all encompassing, total-body move. Y'all enjoy! Hope you have a great weekend :)
*All image sources are from Google Image search