Using an Unstable Bench Press Barbell

Your typical barbell doesn't bend much, even when loaded down with plates. There’s a new type made to be more flexible. It provides an unstable load you have to work harder to control. A study published in the Journal of Strength and Conditioning Research put this tool to the test on the bench press.
 
Fifteen men with several years of weight training experience performed 2 sets of 5 reps using a typical barbell loaded with 75% of their one rep max. Then they repeated this mini workout using a flexible barbell with 60% of their one rep max suspended from elastic bands. Movement of the flexible barbell was less predictable than the traditional barbell. To control the unstable load, subjects had to contract their muscles in a more stable pattern, staying tighter throughout the movement.