Here is another core secret of mine i am showing.It is another thing i relentlessy work on.I upgraded to this from the ab wheel and found this much more challenging and an awsome core strengthener.I do warn you that this is not for those who have weak core as it puts extreme strain on your back and shoulders and can cause serious injury if not done correctly.As you are suspended of the ground while on a pulley system which requires maximum effort to stabilize and use your whole core.Looks easy right?? I still havent seen anyone in the gym who is able to do this!!If you think you have a strong core come and try one of my core workouts and see if you can outlast me,and IF you can i will give you 3 MONTHS FREE TRAINING!!! This is just an example though and i usually do 3min rounds with 15 or 30 sec intervals and changing to different exercises on each change. I am still yet to master a full crucifix…but I WILL!