Variety
A few reasons: 1) Variety---you should always shake up your routine to encourage continuous progress. Having these tapes as part of your collection will provide you with more of a selection when rotating your routines. 2) New exercises----there are new exercises(as well as the classics)to stimulate and recruit new muscle fibers. 3)Focus---Each tape focuses on specific muscle groups through the use of varied rep's, angles, and weight. Volume 1 targets every muscle in the legs with great variety. Volume two targets every muscle of the back, biceps and abdominals with great variety. Volume 3 targets every muscle of the chest, tricep, and shoulder with great variety.