Now entering our third (and final) week of strength training content on A Challenge to Change, and you should be getting stronger every day!

Remember that our challenge this period involves strength training. We've already covered upper and lower body training, but thus far missed one important aspect of health and fitness: core strength.

The core refers to the muscles that attach to the spine and provide protection (along with the rib cage) to your organs - they are your abdominal muscles! Among other things, the muscles of the core provide stability and strength to hold your body upright with good posture. Core muscles include abdominals, hip flexors and rotators, shoulders and lower and upper back.

Some define core strength as the ability to maintain alignment of the middle of the body during movement, in order to enhance the efficiency of your arms and legs, further from the center of your body.

In other words, it's the ability to maintain strength and balance during movement even when your arms and legs are moving through various athletic motions. A stronger core directly affects your upper and lower halves.

Whether you are a runner, walker, biker, or literally any other athlete or person who exercises, core strength plays a direct role in all of your movements and can promote athleticism and strength in doing so.

More than just improved athleticism, injury prevention is another benefit of core training. For example, joint pain is something that is common to bikers, runners, and many other athletes. Some forms of chronic joint pain are the result of poor alignment of your knee and ankle during a running stride, or a bicycle stroke.

Strengthening the muscles of the hip and buttocks can help maintain this proper alignment and reduce stress on the knee joint by easing the pressure placed on your joints - and that, in turn, allows you to run, bike, and follow other exercise plans with a significantly lesser risk of chronic injury and pain.

Just like upper- and lower-body weight lifting, it's important to do core training exercises several times a week and make it a part of your consistent exercise regimen to develop strength and improve your posture.

While core exercises can come in many areas - Pilates, yoga, strength training and many more - the end result is (hopefully) the same: a stronger core which translates to a stronger overall body that will more efficiently handle various exercises and training patterns!

The video this week provides three core exercises to get you started. Once you've built up a safe and consistent base, the Mayo Clinic provides a good slideshow - with visuals - to help you develop a few more difficult exercises that will promote further muscle growth.

