If your shoulders, upper body and core (and I don't mean the apple kind) could use some attention -- this is the day for you. Our celebrity trainer has two quick and easy exercises. So get moving!

On Day 3 of our week-long series, trainer Kathy Kaehler -- whose celebrity clients include Julia Roberts and Kim Basinger -- demonstrates how to strengthen your shoulders, upper body and core.

For those of you unfamiliar with your core, it's the area around your trunk and pelvis. Strong core muscles make it easier to do most physical activities -- from getting a glass off a top shelf to bending down to tie your little ones' shoes. Weak core muscles leave you susceptible to poor posture, lower back pain and muscle injuries. So ladies get ready, get set, get fit!

Day 1: Kathy shows us how to keep those upper arms from flapping in the breeze (don't pretend you don't know what we mean). Using an inexpensive exercise band, Kathy demonstrates a quick and easy way to tighten and tone your biceps and triceps.

Day 2: Kathy demonstrates how to firm and tighten your glutes, hamstrings, and quads with a simple deck of cards and two minutes of time. If you have any concerns about the junk in your trunk then you won't want to miss this!

To buy Kathy's books, click below: