Dumbbell Curl Exercises
The utilization of the dumbbell exercises provides a plethora of anterior upper arm movement
variations. The use of dumbbells provides additional emphasis upon the biceps brachii and brachialis
due to the concept of isolation of the muscles associated with dumbbell training.
In addition, the built-in balance factor associated with barbell training is no longer available and, as such, the requirement of
balancing the weights produces specific taxation upon the muscles which further encourages muscle
growth and development.
The dumbbell movements can be executed with a supinated, pronated, as well as a combination pronation/supination movement application to produce various effects in
an effort to promote the development of the region anterior upper ann. As well, the dumbbell exercises
can be performed with a simultaneous or alternate application which once again allows for a variation
in muscle accentuation.
Considerations for Alternate versus Simultaneous Applications
The recommended approach to take with dumbbell training is to utilize an alternate application versus a simultaneous approach in an effort to provide for maximal isolation (and ultimate stimulation),
of the involved muscles.
If dumbbells are to be employed, it would make sense to apply them in a different manner than that which is employed with the application of the barbell movements.
This would suggest that different movement applications be employed in order to reap the desired benefits associated with dumbbell training.
Simultaneous applications would reduce the proposed benefit of providing for additional isolation upon the muscles.
The question that could be asked is; why use dumbbells if the movement is identical to that which is performed with barbell training?
Another point that could be made for the benefits of employing an alternate dumbbell application is that more weight can be utilized with the
the alternate approach thus providing for increased motor-unit recruitment.
Different Grips and Movement Planes Possible
It should be noted however that different angles-of application can be employed, and different grips can be used to produce a variation of accentuation upon the involved muscles during simultaneous
applications.
An example of these two variations can be found with the seated dumbbell curl performed with an outward grip with the dumbbells brought up to the sides of the body or at a 45°
angle (as opposed to being brought up in front of the body) and a simultaneous application.
Inside-to-outside-movement Application
The use of the dumbbells allows for a variation from the standard up-and-down vertical plane movement application to a unique (oblique), angle-of-application that has the weights contracted
from an inside-to-outside (concentric phase) and an outside-to-inside (eccentric phase) movement application.
It is imperative to raise the pinkie to a position that is higher than that of parallel
with the thumb in order to ensure maximal stimulation of the biceps brachii. The wrist should
also, be held in the hyperextended position in an effort to maximize the accentuation of the biceps
and to alleviate the emphasis of the movement upon the forearms.
Alternate Standing Dumbbell Curl
The utilization of the alternate dumbbell curl exercise allows for the implementation of
an isolation component in a power movement application.
The alternate dumbbell curl movement can be performed with either a seated or standing posture. The standing posture is recommended
as the utilization of hip and knee flexion can alleviate the pressure experienced in the lower lumbar region.
As well, the utilization of hip and knee- flexion allows for a more advantageous
posture for the movement which will provide accentuation into the region of the
anterior upper arms.
The pressure normally felt in the shoulders during the seated application
will be significantly reduced with the standing version of the movement.
The active supination or corkscrew”) the approach is recommended in order
to provide a variation in accentuation that is unavailable with both the barbell and the fixed wrist
dumbbell applications.
Concept of Active Supination (The “Corkscrew” Effect)
There is a strong suggestion put forth that the action of turning (actively supinating) the
dumbbells during the execution of the movement.
In this approach, the dumbbells are placed in the semi-pronated position at the sides of the body and then gradually supinated as they are raised during the concentric contraction phase of the
movement.
During the eccentric phase, the process is reversed with the dumbbells turned back out
(pronated), as they are lowered to the starting position. The actions of supination and pronation take place at about the halfway point in the movement.
It should be realized that contraction of the biceps brachii does not only take place during the action of elbow-joint flexion but also
during the action of supination of the forearm (at the elbow joint).
The action of supination provides an additional torque force upon the biceps brachii offering strong stimulation of both the long and
short heads.
It is suggested that optimum bicep development cannot possibly occur without the benefit of the actions of supination
being applied to them. Many of the world’s most experienced weight-resistance athletes advocate the notion that all the curling
actions in the world will not produce the beneficial effects realized as a result of applying supination during the movement.
The concept of applying the supination action during the movement application differs from that of assuming the supinated
position of the hands before (and throughout), the entire movement application in both the concentric and eccentric phases of the
movement.
With the hands positioned in the supinated position, there is the activation of the biceps brachii short and long heads throughout the movement which allows for the supinated position
of the hands to be maintained over a longer duration.
Of particular significance is the argument presented by those opposed to the “corkscrew” approach is that the biceps (particularly the biceps
short head), is not activated during the final half of the eccentric contraction because the forearm is pronated downward. The action
of pronation removes the emphasis experienced in the biceps and activates the brachialis and brachioradialis muscles.
The counter-argument for the benefit of active supination (“corkscrew”) is that the pre-set supinated position of the hands
does not provide for the opportunity to provide for a torque force to be applied during the raising of the weight.
The opportunity to apply a “corkscrew” effect is said to provide more than adequate compensation for the loss of supination experienced as a result of
pronating the hands during the final half of the eccentric contraction phase of the exercise. It would be a good idea to include one
movement that involves the active supination (“corkscrew”) action during the movement.
Easy Experiment
An interesting manner in which to establish the importance of supination is to place one arm in the half-curl position with the
hand in the semi-pronated position. No weight is required. Slowly turn (supinate) the pinkie upward until it is parallel with the thumb.
“Corkscrew” Curl
You will experience a definite pinching or squeezing sensation as a result of the torque provided upon the biceps.
It is not difficult to determine that with a weight added in resistance to the supination movement increased torque will be placed upon the biceps brachii.
Negative Ramifications of Imbalanced Loading
It has been suggested that placing added resistance to the outside portion of the dumbbell will
facilitate the supination (“corkscrew”) action.
The usage of the term “facilitate” would provide the clue that such approach does not provide for the action of “active” supination but would instead
invoke a “passive” supinated position of the wrists.
By “facilitating” the supination the tension (contraction), is removed, and instead, an extraneous force is used to rotate the hand to the upward position.
This eradicates the premise of supination. As well, it is not always possible to add plates to the outside of the dumbbells as modem equipment design provides for a flat (flush) construction of the
bar and plates.
Older equipment designs would have a protrusion of the bar beyond the plates presumably to allow for additional plates to be added in correlation with the strength increases of the
trainees. Modem facilities offer a full range of dumbbell increments and “fixed” weights are usually provided.
Hands Positioned Just Below Center Point
A much more effective approach that could provide for increased supination would be to slide the hand down the bar of the dumbbell slightly so that the hand is placed just below the center position
of the bar.
This will allow for active supination and the involvement of muscle contraction. You will want to be careful not to bring the hands too far down to the near side end of the dumbbell or
the result will be similar to using added weights (plates) on the outside of the dumbbell: passive supination.
Conversely, You would not want to place the hands too far toward the outer portion of the dumbbell or the supination movement would be too difficult to achieve with the result being that
only partial supination would occur and the benefits related to the supination action would not be fully realized.
Summary of Correct Exercise Execution
Assume the correct preparatory posture by utilizing hip and knee-flexion in effort to provide the
desired flat, rigid posture of the back. The head should be held erect with the chin in a slightly
raised position.
Grasp a pair of dumbbells in a semi-pronated grip and hold them in the fully-extended arm position
at the sides of the body.
Initiate the concentric contraction by raising a dumbbell upward by virtue of elbow flexion.
As the weight is brought to a position in front of the thighs begin supinating the wrists upward
while focusing fully on directing strong neural-impulsing into the biceps brachii (not the forearms).
You will want to resist the urge to drop down with the shoulder in effort to apply leverage
to the lift. You will also want to avoid the tendency to lean back during the lift in effort to
apply momentum into the movement.