Our quest to explain every weird thing at the gym has now landed on Fat Gripz, the heavy rubber handles, often blue, that you can wrap around barbells and dumbbells. Their main job is to make the bar harder to hold onto, which can be a good thing.
(Fat Gripz is one popular brand, but it’s often used as a name for the whole category of object. There are multiple sizes of Fat Gripz, plus other brands, like Alpha grips.)
They give your gripping muscles an extra challenge
It’s harder to grip something wide than something narrow. If you’re lifting a normal sized barbell or dumbbell, your fingers and thumb wrap around it. But if you’re lifting something bigger, you need to squeeze with your hand just to be able to hold on. That requires your hand and forearm muscles to work harder.
Some bodybuilders like fat gripz for this reason, because they simply want bigger and stronger forearms. There are also barbells and dumbbells that are made with larger handles (like the axle bars often used in strongman competitions) but they can be harder to find.
They can help you train for thick bar lifts
There are challenges and competitions where you might need to lift something with a thick handle. I once had a meet where I knew I’d need to deadlift a 2″ wide bar. I didn’t have one, so I carried blue Fat Gripz in my gym bag, and trained with them on the regular barbells at my gym.
There are also competitions that exist specifically to test grip strength, and if you’re training for those, Fat Gripz can be one of the tools you use. If you’d like to try this informally, r/griptraining is holding an online challenge right now to see who can pick up the heaviest dumbbell with a fat handle.