Weightlifters often play around powerlifting bars while resting between sets. However, that twist has a motive beyond entertainment.
Olympic bars are supposed to rotate, but more importantly, if we're going to perform Olympic-style lifts, it's essential that the bar sleeves rotate.
Reduce twist
Powerlifting bars are supposed to rotate to reduce torque during explosive movements and make it safer for the wrist, forearm, and elbow. In Olympic weightlifting exercises like a snatch, a twist bar is essential to minimize injury and improve comfort.
The sleeves are the part of the bar that they sit on. the discs and are designed to rotate for safety reasons. It has a lot to do with physics, and it's important that they rotate. This is not to say that all bars rotate, as some do not have that functionality.
The dumbbells have swivel sleeves to not only make the lifts easier to do, but also much safer. This is especially true of Olympic lifts, like the snatch and the clean and jerk. The point is, when we move a barbell, especially with major movement transitions like Clean the Jerk, rotating sleeves allow the weights to rotate. This allows some of the inertial force of the plates to disperse, which means less force on the body and less risk of injury.
Essentially, the twist removes some of the force that would be placed on the wrists and elbows, so you don't take the full impact of the lift on those vulnerable joints. Even for lifts that aren't as stressful on the wrist and elbows, twist sleeves help reduce stress and keep the lifter safe.
On top of that, since the sleeves allow the weights to rotate, this prevents the entire bar from rotating in the hands, something we don't want to happen when a specific grip is required.
How to make it spin well?
We may have a bar with swivel sleeves, but it doesn't spin as smoothly as we want. Maybe that bar just doesn't have that good spin in the first place, or maybe it does, but over time the spin has gotten worse and the sleeves have become "stickier."
Since twisting is such an important part of safe weight training, this is something you'd probably be inclined to correct, or at least improve. Fortunately, it is not that difficult to do this. Most of the time, a little lubrication is all we really need.
It's generally best to avoid oil-based lubricants, as oils tend to attract dust in the long run. However, they can be used if you have no other alternative. The white lithium grease and el silicone lubricant Waterproof are usually better options, although there are many alternatives.
All we need is to get the lube between the sleeve and the actual bar, making sure to rotate the sleeve so that the lube coats the entire inside. This does not require us to remove the entire bar sleeve, although we can if we deem it necessary. As long as we lubricate their spinner sleeves from time to time, they should spin pretty well. Of course, it's important to remember that some powerlifting bars have better spin than others due to their construction. No amount of lubrication is going to change that.