This is from the latest NSCA online issue. I was wondering what you guys think. I ma not familiar with some of the equipment, practices etc coming from a regional University in Australia. Perhaps this is a reversal of the old saying “It works in theory but not in prctice” ? 
Adding Chains and Elastic Bands to Weights Does not Increase Effectiveness of Squat Exercises (12/10/02)
Researchers from Marquette University have determined that using chains and elastic bands is no more beneficial than traditional barbell training for the squat exercise. Theoretically, augmenting either chains or bands to the barbell will increase the loading during the ascent phase. In sum, the load increases as the mechanical advantage increases. But no research has evaluated the purported advantages of these training claims. The purpose of this study was to assess motor unit activation, rate of force development, and peak force development of these variations of the squat.
Researchers examined EMG data for the quadriceps and hamstring muscle groups, as well as mean and peak vertical ground reaction forces, for three conditions of the back squat. The squat conditions were 1) barbell and plates, 2) the barbell with plates and weighted chains, and 3) the barbell with elastic bands. The band and chain conditions were adjusted to equal the barbell condition. Eleven Division I athletes familiar with the squat techniques participated in the study.
After statistical analysis there were no differences found between any of the groups in ground reaction forces or EMG activity. This lack of difference throws doubt on the usefulness of performing squats combining barbell and weight plates with chain and elastic resistance.
Ebben W, Jensen R. (2002). Electromyographic and Kinetic Analysis of Traditional, Chain, and Elastic Band Squats. Journal of Strength and Conditioning Research, 16(4): 547 - 550.