I will describe how I do overhead supports using a dumbell. First you need a product that is available called POWER HOOKS. Google it. This device lets you hang the dumbell from a barbell . I set the barbell at the appropriate height for me on the top of my power rack, depending on the height of your own rack, you may need to improvise to get it right. This allows me to get under the dumbell in a partial squat position with my arm extended. The movement is just like the barbell version but done one arm at a time with a dumbell. Since the range of motion is so little the way the hook is designed lets you push the dumbell up in ALMOST complete safety as the hook prevents much sideways movement. You still need to be careful as it is still possible to release the dumbell and could cause serious injury. ( you will see what I am talking about when u do this) I use an adjustable olympic dumbell bar. use plates no larger than 25 lb olympic plates. although I have used 35 lb plates on occassion , but this limits the range of motion even more as the plates hit the bar sooner. All the midsection muscles are worked extremely well with this movement. Spinal errectors, abdominals, obliques, along with the lats, traps, mid back muscles, chest, delts, triceps, glutes, quads and hamstrings. Even calves. This is a total body movement that most have never heard of, definitely should be included in a strength training routine!Mix it up a bit, sometimes use the dumbells and sometimes use the barbells.