Assistant editor Caitlin Carlson is training for a triathlon in just thirty days! Here's the strength-training workout she uses to make sure her hips and core are race-ready. For more details about her 30-day training period, check out Tri in Thirty!

Perform each move for 30 to 90 seconds (when you’re focused on banging out a certain number of reps, your form may suffer—but a time-focused workout allows you to do as many good reps as you can in the allotted time). Then rest for 30 to 60 seconds between moves, and after you’ve completed all the moves, rest for up to two minutes. If you have time, repeat the entire circuit.

1. Glute Bridge March

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Lie on your back with your knees bent and your feet flat on the floor. Rest your arms on the floor, palms up, at shoulder level. Raise your hips so your body forms a straight line from your shoulders to your knees. Brace your abs and lift your right knee toward your chest. Hold for 2 counts, then lower your right foot. Repeat with the other leg.


2. Superman

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Lie across a stability ball, feet hip-width apart and resting against a wall or other sturdy object. Your arms should be extended past your head, with your palms facing each other. Squeeze your glutes and lift your chest off the ball to straighten your back while reaching your arms overhead. Pause, then slowly reverse the motion to return to start.


3. Lateral Band

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Tie a resistance band in a small loop. Step inside the band, placing it around your ankles or just below your knees, then clasp your hands in front of your chest for balance and sink into a squat, your chest and eyes up. Step one leg out to the side in the squat position to create tension in the band, then bring the other leg in so your feet are together again. Step sideways 10 times in one direction, then step 10 times in the opposite direction.


4. Mason Twists

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Stand and hold a medicine ball or dumbbell with arms extended straight out in front of you and a natural bend in your elbows. Rotate from side to side and use your core (your abs and hips) to control your movement.


5. Side Planks

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Lie on your right side with your legs straight. Prop yourself up with your right forearm so your body forms a diagonal line. Rest your left hand on your hip. Brace your abs and hold. Be sure your hips and knees stay off the floor.


6. V-ups

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Lie face-up on the floor with your legs and arms straight. Hold your arms straight above the top of your head. In one movement, simultaneously lift your torso and legs as if you're trying to touch your toes. Lower your body back to the starting position. (If this is too difficult, you can bend your knees and pull them toward your chest instead).


7. Clamshell

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Lie on your left side on the floor, with your hips and knees bent 45 degrees. Your right leg should be on top of your left leg, your heels together. Keeping your feet in contact with each other, raise your right knee as high as you can without moving your pelvis. Pause, then return to the starting position. Don't allow your left leg to move off the floor.


8. Hip Hikes

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Stand on a step at least four inches high with one foot hanging off the side, hips squared forward and shoulders level. Keeping your standing leg straight, raise your free hip directly upward and then drop the leg back to the starting position. Do as many as you can do in 30-90 seconds, then switch legs.