If you have been doing squats, deadlifts or Olympic lifts for any amount of time, you no doubt appreciate the importance of a strong core. Maintaining a strong core is vitally important to preventing back injury and performing better lifts. One cheap and extremely effective way of building a strong core is through the use an ab wheel. While this piece of equipment may have gone out of fashion of late, anyone that has used it can attest to its ability to work and strengthen your whole abdominal area unlike any other piece of equipment. The cool thing about it is that you can make the exercises progressively harder (if not impossible) by using variations of the basic movement. The ab wheel is also perfect if you are nursing a back injury and are trying to avoid regular crunches. Here are some video links to give you an idea of what is possible. Enjoy!