), so shoring them up is key.

The former is a dynamic abs exercise.

When doing mountain climbers, concentrate on keeping your core tight and your back flat.

fitness challenge week 4

Katie Thompson

This strength session below is for Day 9.

Dont forget to check out the full month of workoutshere, or go to the workout calendarhere.

Workout Instructions:

Do each move below for your selected period of time and rest.

squat pulse

At the end of all the moves, rest for 60 seconds.

That’s one circuit.

Do the entire circuit three to five times.

mountain climber

Bonus: Quick Finish

Do each move for 30 seconds each, back-to-back, no rest.

Repeat for two minutes.

Squat Pulse

Stand with your feet hip-width apart and core engaged.

lateral lunge

take a stab at stay low and not stand up entirely for the full amount of time.

This is the starting position.

Keeping your core tight, draw your right knee to your chest.

russian twist with dumbbell

Return to the starting position and immediately draw your left knee to your chest.

Return your left leg to the starting position.

That’s one rep.

Continue to alternate.

russian twist with dumbbell

The quicker you move your legs, the more of a cardio challenge this will become.

double-check to keep your core engaged and back flat throughout.

If you have to slow down to maintain form, that’s fine.

mountain climber

Once your selected time interval is over, switch to the other side and repeat.

Lateral Lunge (right side)

Stand with your feet together and your hands on your hips.

This is the starting position.

Take a big step (about two feet) out to the right.

Pause for a second and then push off your right leg to return to the starting position.

That’s one rep; repeat.

Lateral Lunge (left side)

Take a big step (about two feet) out to the left.

Keeping your abs engaged, twist your torso from right to left.

Optional:Hold one dumbbell in both hands as shown.

BONUS: Quick Finish

Bonus Move 1: Russian Twist

Bonus Move 2: Mountain Climber