Thick bar training is nothing new, it has been around for decades in one form or another.
It has become very popular recently due to products such as “Fat Gripz” that make it easier to utilise.
Before, you either needed a specially designed thicker bar, or you used towels to artificially thicken the bar – but this could affect your grip on the bar because towels can be slippery.
Fat Gripz just attach onto the bar and can be taken off again afterwards.
There is some debate as to whether thick bar training is worth it or not, people who agree with it point to this 1992 study by Grant, Habes, & Steward .
This study found that the thicker the bar, the more neuromuscular strength is required to perform the exercise. This will cause your forearms to grow much stronger, and therefore when you change over to regular grip exercises, you’ll be able to lift more weights.
Those arguing against thicker bars point to the 2008 study by Fioranelli & Lee  who found that the narrower bar actually produced greater forearm strength than the thicker bar.
But as this Poliquin Group article points out, the study used the barbell bench press, which is not the ideal exercise for thick bars as it involves pressing. Same goes for shoulder presses, as the extra thickness can lead to safety issues.
As you will discover, thick bar training does not suit every exercise.
A lot of people use it for the bench press, but it really isn’t ideal for it. From a safety aspect, and from a technical aspect.
Thick bar training would also be pointless for most lower body exercises, as you just don’t require a strong grip to barbell squat or to lunge. Deadlifting could potentially work, but rack pulls would probably be a better choice.
Exercises that Benefit from Thick Bar Training
The most commonly performed thick bar exercise is the barbell bicep curl, this exercise works for a number of reasons.
It is perfectly safe – you’re not going to lose your grip and drop the bar on your head like you could in a shoulder or bench press!
It’s a pulling movement of sorts, so it suits the thicker bar. The bicep curl is already designed to work the forearms to some extent, and you can really concentrate on the eccentric part of the lift (which seems to work really well for thick bar training).
You can also use Fat Gripz on dumbbells and perform a dumbbell bicep curl, or even a Hammer Curl, which would increase forearm and grip strength even more.
Another exercise that seems well suited to thick bar training would be the underhand barbell bent over row. Again, it is a pulling exercise so there are no safety issues to concern yourself with, it also is supposed to target the biceps and forearms (though the main muscles to work would be the upper back muscles).
You can also include the overhand barbell bent over row in this, or even the single arm dumbbell row.
As we mentioned earlier the rack pull is a great exercise for thick bar training. It has a shortened range of motion compared to the barbell deadlift, and it is specifically designed to not only increase the amount of weight lifted, but to improve grip strength.
The final exercise that we will look at (though there are of course many more that might suit thick bar training) is the barbell/dumbbell shrug. This exercise is simple to perform, involves a short range of motion, and is a pulling movement.
It is also a great grip strengthening exercise, though it is primarily designed to strengthen the trapezius muscles.
When not to use Thick Bar Training
One thing should be made clear, always using a thick bar is not going to get you amazing results.
While thicker bars can increase the neuromuscular strength of the forearms, you need to reduce the weight, and therefore you will not be recruiting as many muscle fibres in the muscles you are supposed to be targeting.
A thick bar bicep curl will help improve your grip strength, but won’t hit your biceps quite as hard as a regular barbell bicep curl.
So maybe use the thicker bar for a couple exercises a week, rather than for every exercise.
Do this for a 6-8 week period and then perform the exercises without the thicker bar.
Measure your results too, so that you can make your own mind up as to whether thick bar training works for you or not.
 Grant, K., Habes, D., Steward, L. 1992. An analysis of handle designs for reducing manual effort: The influence of grip diameter. International Journal of Industrial Ergonomics 10(3): 199-206
 Fioranelli, D., Lee, C. 2008. The influence of bar diameter on neuromuscular strength and activation: inferences from an isometric unilateral bench press. Journal of Strength & Conditioning Research 22(3): 661-6