Though it’s been pretty well established that bicep curls are an effective isolation exercise, there is still some debate as to how this classic bodybuilding movement is meant to be performed.
The execution of a bilateral bicep curl with either an EZ-curl bar or standard straight barbell can alter certain characteristics of the exercise, making one variation more suitable than the other depending on the goals of the lifter.
To put it short, the EZ bar bicep curl is considered to be easier on the wrist joint but generally lighter than the straight barbell bicep curl - other factors like muscular activation, range of motion and movement pattern remain relatively the same.
The main and most obvious difference between an EZ-curl bar and a standard straight barbell is in the shape of the bar itself.
Straight barbells are shaped in such a way that the exerciser’s wrist is somewhat bent towards the side when performing a supinated exercise like the bicep curl. This is not so much the case with an EZ-curl bar, where the “S” shaped bends of the barbell allow the wrist to maintain a more secure and advantageous position during such exercises.
Apart from the actual shape of the barbells themselves, the weight of the standard olympic straight barbell is considerably heavier than the majority of EZ-curl barbell brands, as a standard straight barbell will weigh 45 pounds or 20 kilograms while unloaded. This weight may be difficult to curl for novice exercisers.
Due to the greater length of a straight barbell and the fact that it allows the lifter’s muscles to contribute a greater amount of force to the movement, many individuals will notice that their capacity to load on weight is greater with a straight barbell than an EZ barbell.
Due to the positioning of the wrist and elbows when curling with a straight barbell, the biceps brachii muscle is recruited to a greater degree than with an EZ bar - albeit by a rather small margin.
This is a consequence of the fact that curling with the wrists bent inwards will engage both primary biomechanics of the biceps brachii, resulting in greater potentiation as the demand is increased.
For lifters that work out in public gyms, the presence of an EZ bar may not exactly be guaranteed.
However, there is no doubt that a standard straight barbell will be present, as it is the quintessential free weight training item. In the event that your gym does not have an EZ bar available, substituting with a straight barbell should be perfectly adequate.
EZ barbell curls are arguably one of the safest ways to go about performing bicep curls, as they place the wrist and forearms at a far more neutral and advantageous positioning than other types of equipment.
This equates to significantly reduced incidence of pain or other symptoms of injury that are normally associated with barbell-based curl exercises.
In particular, EZ barbell curls are especially useful for individuals with a history of wrist instability or otherwise poor mobility in the joints of their hands and wrists.
Due to the more advantageous forearm position of EZ barbell curls, a marked increase in dynamic brachioradialis and brachialis recruitment can take place - two muscle groups that are notoriously difficult to directly target with isolation exercises.
Inducing hypertrophy of these muscles can result in a more “3-D” look to the lifter’s upper arm, as well as improved forearm stability and reinforcement of the elbow extension biomechanic.
As was touched upon briefly earlier in this article, the main difference between the EZ bar curl and the straight barbell curl lies in the positioning of the lifter’s wrist.
A straight barbell curl will involve performing the movement with the wrist firmly held in a supinated position, regardless of their relation to the elbow and forearm. For individuals with poor wrist mobility, this can be uncomfortable and potentially injurious.
Conversely, EZ bar curls allow for a more neutral wrist position, creating a more natural movement and reducing stress on the joint.
However, this change in wrist position will also alter the recruitment of the biceps brachii, as maintaining a supinated wrist will cause the biceps to be engaged to a greater degree as would be in-line with their natural biomechanics.
In terms of relative injury risk, EZ bar curls are well-established to be superior to straight bar curls across the board.
Whether it be due to less tension placed on the wrists, easier adherence to proper form due to the shorter size of an EZ barbell or simply a lesser loading capacity, EZ bar curls are far less likely to result in injury than straight bar curls.
This is not to say that straight bar curls will result in injury however, as performing them with correct form and proper mobility drills will greatly reduce the risk of any acute damage taking place.
While concerns over maximal loading capacity are more of an issue for advanced level lifters, it is nonetheless an important point of distinction between bicep curls using an EZ bar or straight barbell.
Because of the fact that the EZ bar curl is shorter, lighter when unloaded and places the forearms at a more natural angle, a marked difference can be found in terms of maximal load potential between the two types of curls.
Generally, straight barbell curls will allow for more plates to be loaded onto the barbell, alongside the fact that more force output will be possible from the lifter as their biceps are recruited to a greater extent.
Though we do not recommend attempting very heavy bicep curl repetitions, more experienced lifters who have already reached such a level of strength may wish to make the switch from EZ bar curls to straight barbell curls so as to maintain resistance-driven progressive overload.
To summarize the rather few actual differences between an EZ bar curl and a straight bar curl, it can be said that the former exercise is more appropriate for less experienced lifters, or those with a history of injury in the arms.
Otherwise, the straight barbell bicep curl may be more appropriate for exercisers of a more advanced level - so long as they are confident in their form and are relatively flexible in the wrists and elbows.
In truth however, both of these exercises are likely to yield the same results over the long term, and deciding between the two is more a matter of comfort than actual effectiveness as biceps exercises.
1. Marcolin G, Panizzolo FA, Petrone N, Moro T, Grigoletto D, Piccolo D, Paoli A. Differences in electromyographic activity of biceps brachii and brachioradialis while performing three variants of curl. PeerJ. 2018 Jul 13;6:e5165. doi: 10.7717/peerj.5165. PMID: 30013836; PMCID: PMC6047503.
2. Oliveira, L.F.; Matta, T.T.; Alves, D.S.; Garcia, M.A.; Vieira, T.M. Effect of the shoulder position on the biceps brachii emg in different dumbbell curls. J. Sports Sci. Med. 2009, 8, 24–29.