Get Fit in 90 Days: Week 7 (The Plan)

"Each day you will finish with a new exercise to strengthen your lower back (and overall core)." says Sara Haley, of Sara Haley Fitness and the creator of our 90-day workout plan. Use this week to really focus on your muscles and how you execute each move.

Monday: Cardio Session

If you are on your own, take this outside or jump on a stationary bike. Take 5 minutes to warm up. Just like last week, you will be spending less time in your “comfortable” zone and more time in your "uncomfortable" zone. For 3 minutes find a pace you find challenging but manageable. Then for 30 seconds push to a place where you think you might run out of breath. Whether outside or inside, this will require you to change to a higher gear and push! Lighten your gear for 30 seconds and catch your breath. At the end of this 30 seconds you want to feel ready to go again. Repeat the 3 minutes of "uncomfortable," then take it to 60 seconds anaerobic work, followed by the 30 seconds of recovery. You are going to do this 2 more times increasing your anaerobic work to 90 seconds and then 120. Cool down for 3-5 minutes. This entire workout should take you just under 30 minutes.

• Lower Back Exercise #1: Opposition Reach: On chest with arms and legs stretched out long. Reach right arm and left leg off floor at the same time. Hold for a count of two. Repeat with left arm and right leg. Keep head in line with body and core engaged the entire time. Continue alternating for a set of ten.

Tuesday: Lower Body Circuit 1

After performing a 3 minute cardio warm up of jumping jacks, jogging in place or jumping rope (3 minutes of one or 1 minute of each), you will pick one to repeat between each lower body exercise (or you can alternate) for 60 seconds, followed by 60 seconds of rest, before starting the next lower body exercise. Make sure to finish with your lower back exercise.

• Lower Body Exercise 1: With chest lifted, squat with feet together. Step out with right foot and squat with feet shoulder distance apart. Bring right foot back in and squat with feet together. Repeat left. Continue alternating for a set of ten and then pick up your pace for a set of ten. Targets glutes, quads and hamstrings.

• Lower Body Exercise 2: Step out into a side lunge with right leg. Make sure to keep left leg straight. Push off right leg to return to feet together. Repeat 12 times on the right and then on the left. Targets glutes, outer and inner thighs.

• Lower Body Exercise 3: Stand on right leg with left foot tapped behind you. Hinge forward at the waist with right knee soft. Squeeze the gluts to slowly come up. If you feel balanced lift up left leg as you lower down. Repeat for a set of ten before switching sides. Targets glutes and hamstrings.

• Lower Body Exercise 4: Plie squat with hips rotated out. Push off and bring right knee up to hold. Repeat on left. Continue alternating for a set of 20. Targets inner thighs.

• Lower Back Exercise #2: Double Reaches: On chest with arms behind back and legs stretched out long. Lift upper body up. Hold for a count of two. Repeat for a set of 8. Then, reach both legs up off floor. Hold for a count of two. Repeat for a set of 8.

Wednesday: Cardio Circuit

You'll need a stop watch or a clock that you can easily see during your workout. Head outside or jump on a treadmill and warm up for 5 minutes with a nice walk or jog. Today, we'll be spending less time in your "comfortable" zone and more time in your "uncomfortable" zone. Whether you are walking, jogging, or running you need to pay attention to how it feels in your heart and lungs. These are the muscles we are trying to make stronger.

• 0:00 - 5:00, warm up with a walk.

• 5:00 - 8:00, find a pace you find challenging but manageable.

• 8:00 - 8:30, push to a place where you think you might lose your breath. You should feel like you couldn't possibly do or give any more. (This is referred to as working anaerobically or without oxygen.)

• 8:30 - 9:00, recover

• 9:00 - 12:00, jog

• 12:00 - 13:00, run or sprint

• 13:00 - 13:30, recover

• 13:30 - 16:30, jog

• 16:30 - 18:00, run or sprint

• 18:00 - 18:30, recover

• 18:30 - 21:30, jog

• 21:30 - 23:30, run or sprint

• 23:30 - 28:30, cool down

• Lower Back Exercise #3: Full Reaches: On chest with arms behind back and legs stretched out long. Reach both arms and legs up at the same time. Hold for a count of two. Repeat for a set of 8.

Thursday: Cardio Session

Repeat Monday's Cardio Workout followed by Upper Body Circuit 1 without the cardio intervals. Remember to finish with Lower Back Exercise #4.

• Lower Back Exercise #4: Swimming Reaches: On chest with arms and legs stretched out long. Reach both arms and legs up at the same time. Flutter arms and legs for a count of six. Lower down and repeat for a set of 6.

Friday: Fitness Class

Take a pilates class, it's the best lower back and core strengthening program out there!

Sara Haley (sarafitness.com) is a Fitness DVD Personality, Master Trainer and Creative Consultant for Reebok.