The 12 days of fitness: A fast workout challenge to keep you healthy this holiday season

Stand tall with your feet hip-distance apart and arms elevated overhead.

Simultaneously pull the right knee up and arms down so they fall at the sides of the leg. Squeeze the abs in a crunch-like motion without hunching. Release and repeat on the opposite side. Continue this sequence for 100 reps (50 per side).

Briskly pump the arms and legs as you land lightly on the balls of your feet. Avoid locking the knees when jumping; rather, keep them soft to reduce impact each time you land.

From a plank position, with the hands aligned beneath the shoulders, spine straight, and head inline with your spine, drive the knees up one at a time for 50 counts (25 reps per side).

Lie on your back with the legs bent and parallel. Extend the arms to the sides with palms facing down for support. Press your lower back into the floor to engage your abdominal muscles and support your spine.

Push through the heels to elevate the hips until they form a straight line with the shoulders and knees. Squeeze your tush for two counts, then lower the hips back down until they are hovering an inch above the ground.

Assume a a plank pose (hands flat on the ground, shoulder-width apart, back and legs straight with toes curled under). Engage the core and tuck elbows close to the ribs.

Slowly lower down toward the ground until your chest is about five inches from the floor. Hold for a count, then push through your palms to lift back up. Remember to breathe evenly, as it’s common to hold your breath during exercises such as this. Inhale through the nose on the downward phase and exhale through the mouth on the way up.

With your feet hip-width apart and weight in your heels, keep the hands balled into fists in front of the shoulders.

Hinge back at the hips and press through the heels to stand and push your fists up toward the ceiling.

Simultaneously, lower the arms and bend down to squat again.

Stand facing a foot or so away from the first step on your stairs, or if you don’t have stairs a platform that’s roughly the same height works well.

Rest the top of your right foot on the step and your hands on your hips. Slowly bend the front knee to lower the body until it forms a 90-degree angle. The front knee is over the ankle. This takes considerable balance, so move slowly to keep proper form.

Push through the front heel to stand. Perform 25 reps, then switch sides.

Plant your entire foot flat on a step or sturdy platform, making sure the heel isn’t hanging off.

Push through your heel to stand and pull your opposite knee up toward the chest without hunching. Repeat 30 times, then switch sides.

Using either a soft surface such as a rug, or for more of a challenge, the first step on your stairs, position your body into a side plank. Align the shoulder over the elbow and form a straight line from the head down through the heels.

Slowly dip your hip down toward the floor without making contact. Hold for a count, then return to the starting stance. Repeat for 25 counts, then repeat on the other side.

From the same step or platform, position the entire right foot flat on its surface. Push through the heel to stand and drive the opposite knee up toward the chest.

Step back down with the left leg and then step the right leg back, lowering into a reverse lunge. The back knee should be directly under the hip. Continue this sequence for 25 reps, then try it on the other side. If it’s easier, you can break this movement up into two separate exercises: a step up and a reverse lunge.

Stand tall with the feet wide and hands balled into fists in front of the chest.

Simultaneously punch out the right arm and pivot on the ball of your right foot. Your gaze should follow the direction of your punch. Quickly pull the arm back in and switch to your left side, pivoting on the ball of your left foot. Repeat alternating punches for 100 counts (50 a side).

Pretend you’re holding a jump rope in your hands and position them so the hand is at elbow height.

From the balls of your feet, keep your knees slightly bent as you jump for 100 counts. Make small arm circles, as if rotating a rope with your arms. To reduce impact on the knees, keep jumps low and your landing soft.