Dumbells or Barbells: which is most effective?

[ILiftBig]

I thoght I would pass this research study on done at the university of Michigan MVS 330 web page. The whole study can be read at their web site. I would put the link but I guess I am not allowed.


DISCUSSION
Many of the angles in both the barbell bench press and the dumbbell bench press proved to be quite similar; however, there were certain observed variances that helped to account for the increased difficulty of the dumbbell bench press. The primary difference occurred in the initial angles at the elbow joint in which the starting angle for the dumbbell bench press was less than the initial angle in the barbell bench press. The difference in the initial elbow angle resulted in different segment angles at the forearm which lead to the different locations of the centers of mass. Other variances were seen in the initial angles at the shoulder and upper arm segment angles that were more perpendicular at the onset of motion for the dumbbell bench press. Also, both the elbow and shoulder joints went through greater ranges of motion during the dumbbell bench press, which helped to add to the increased difficulty that was experienced while performing this exercise.

The differences described above helped to provide strong evidence as to the causes of the dumbbell bench press being more difficult than the barbell bench press. From a mechanical standpoint, the most significant areas focused on the elbow joint, for the actions about its axis provided the basis for the variances observed at the other joints and segments. In the dumbbell bench press, the initial elbow angle was approximately 9 degrees less (161 degrees) than the initial angle for the barbell bench press (170 degrees). Combined with a smaller initial shoulder angle and an upper arm segment angle that was smaller in relation to a perpendicular plane, these elements caused the forearm, and thus the weight, to be held more vertical in the dumbbell bench press. The significance of this was that the horizontal component of force, which resulted from a greater forearm segment angle, was decreased when the weight was held closer to the perpendicular plane running through the elbow joint. This limited the amount of torque about the shoulder and thus reduced the component of force that the horizontal adductors needed to generate to stabilize the shoulder. Because the dumbbells were not connected as the barbell was, the horizontal force could not be canceled by equal an opposite components created by each arm. Therefore, each dumbbell needed to be held in close proximity to the perpendicular vertical plane in order to limit the amount of torque producing horizontal abduction about the shoulder. The adjustment in the forearm segment angle was best seen in the center of mass graph, in which the center of mass for the dumbbell bench press was located medial in relation to the barbell bench press as a result of the forearms being more perpendicular during the dumbbell bench press. Through reducing the amount of torque during the dumbbell press, the mechanical advantage for the pectoralis muscles were decreased and the exercise relied more on the efforts of the triceps, which happen to be a smaller, and weaker muscle group than the pectoralis muscles. This, in turn, contributed to the dumbbell bench press being more difficult to perform than the barbell bench press because the weaker muscle group (triceps) had to contribute to the movement of the dumbbells more so than they had to for the barbell bench press. Another factor that contributed to the dumbbell bench press being harder to perform than the barbell bench press was the presence of torque about the shoulder joint. Although adjustment was made to limit torque at the shoulder when performing the dumbbell bench press, a magnitude of torque still existed. In order to stabilize that force, wasted recruitment of the shoulder adductors was needed to prevent horizontal abduction. The presence of this torque was best seen in the excess horizontal motion that occurred in the dumbbell bench press. Conversely, horizontal motion of the barbell was minimal when compared to the dumbbells as the horizontal adductors did not have to stabilize excess torque. Instead, these muscles were better able to contribute a greater amount of force to lower and raise the barbell. Finally, the range of motion at the elbow and shoulder joints were greater during the dumbbell press than during the barbell bench press. This was most likely the result of the bar limiting further flexion and horizontal abduction at the elbow and shoulders, respectively. The greater range of motion introduced the pectoralis muscles to an adverse mechanical position during peak horizontal abduction, which limited their ability to overcome a greater force during the barbell bench press. In conclusion, three elements factored into the increased difficulty of the dumbbell bench press. They included: torque caused by the decreased stability of the dumbbells versus the barbell required wasted shoulder adductor muscle force in order to stabilize the weights, compensation for the lack of stability resulted in decreased mechanical advantage of the pectoralis muscles, and a greater range of motion in the dumbbell bench press reduced the force production throughout portions of the exercise.

Several limitations that existed in the experiment could have been improved upon to increase the validity of the conclusions. First, the positions at which the arm segments and the corresponding shoulder angles produce maximal mechanical advantage of the pectoralis muscle could have been acquired. In the experiment only generalizations fromed from personal experience were implied. The exact positions could help to determine what proportion muscle mechanics contributed to the ease with which the barbell bench press was completed compared to the dumbbell bench press. The exact torque values created by the dumbbell could have also been calculated in order to provide a more accurate view of the magnitude of force that must be generated by the horizontal adductors to compensate for the torque in the dumbbell bench press. Finally, it also would be necessary to test more subjects to determine the consistency with which the conditions found existed.

 

[lightemup]

dumbells, as long as you do it right. keep your palm of your hand facing your chest on the way up as well as on the way down.

 

[suncloud]

for sheer bulking barbells are better - simply from the amount of weight you can use. for cutting, sculpting, or anything else i'd stick with dumbells.

 

[Marsh11]

Gotta mix it up and do both

 

[holdcenter]

dumbells seem to help me with my shoulder injury.

 

[BodyWizard]

Gotta mix it up and do both

Like the man sez: mix it up - use both (I do)

 

[russy_russ]

I start with barbell, then move to dumbells varying the sets/reps geared towards my goals...

 

[motiv8er]

DBs because of all my injuries...

 

[jamesb2525]

for sheer bulking barbells are better - simply from the amount of weight you can use. for cutting, sculpting, or anything else i'd stick with dumbells.

agreed

 

[Joshua86]

Gotta mix it up and do both

Bingo

Both have their advantages, so you have to figure out how to utilize them to your full advantage.

I think a lot of it depends on your genetics and muscle structure, especially when it comes to how you're training the chest. Some people are gifted enough to only need a handful of chest exercises to get great development, while people like me have to hit the chest from as many different angles possible just to get development (and it still comes slowly). For example, parallel chest dips don't work for me, as my triceps end up taking most of the load, even when I'm really trying to focus on my chest. I eventually figured out that decline presses - both barbell and dumbbell - and decline flyes are the best way for me to stimulate the lower part of my chest. So what I'm getting at is that you have to figure out what works best for you. Trail and error.

 

[brk_nemesis]

what ever works. Barbells work good for me on some while DB's are better on others. Db shoulder presses dont do crap for me, barbells do,....but DB standing rows are god's gift to mankind.

 

[silverSurfer]

I use both - variety is good.

 

[t-bone2]

From the Analysis:

The subject selected to perform the flat barbell bench press and the dumbbell bench press was a twenty-year-old male.
This is only a sample size of one (as was noted at the very end of the discussion on the analysis.) While some information can be deduced regarding the motion analysis, no guarantee that everyone will perfrom their BB vs. DB benching the same as this individual. Also, based on the video, the DBs at lockout are with hands seperated at a distance similar to the BB bench. Many (most?) push the hands together so the DBs touch or almost touch at lockout.


For each trial, the same total weight of 63.6 kilograms was used.
While Suncloud is correct in his assumption, it obviously won't apply to this analysis.


Flexion at the elbow during the barbell bench press occurred for 1.06 seconds (52% of the total time elapsed) and extension at the elbow lasted for 0.99 seconds (48% of the total movement time).

For the dumbbell bench press, flexion and extension at the elbow took 1.48 seconds (54% of the total movement time) and 1.19 seconds (46% of the total movement time) to complete, respectively.
The Time Tension Integral is 30% longer per rep for the DB press.


Joint velocity. (Angular Kinematics) During the barbell bench press peak flexion velocity for the elbow was 144 degrees per second, while peak extension velocity was -279 degrees per second. For the dumbbell bench press, elbow angular velocity had a peak flexion velocity was 236 degrees per second, while peak extension velocity was -283 degrees per second.

Angle-Angle Plot. (Angular Kinematics) In the barbell bench press, the range of motion at the shoulder joint seen at the shoulder (73 degrees) was less than the range of motion observed at the shoulder during the dumbbell bench press (81 degrees).
Greater ROM with DB bench.


Joint Position. (Linear Kinematics) In the barbell bench press, the horizontal displacement of the elbow joint was .13 meters. This maximal displacement occurred during the ascension of the weight. The vertical displacement of the elbow joint was .42 meters. This also occurred during the ascension phase. During the dumbbell bench press, the horizontal displacement was .24 meters, and the vertical displacement was .48 meters. Both maximal displacements occurred during the ascension of the weight

Joint velocity. (Linear Kinematics) For the barbell bench press, the velocity component of the joint mirrored the vertical velocity with only rare moments of horizontal velocity of any significance. The maximum horizontal velocity achieved was 0.81 m/s. This occurred during the ascension of the weight. The minimum velocity was 0 m/s, which occurred as the motion reversed vertical directions as well as at the end of the motion. During the dumbbell bench press, there was more horizontal velocity affecting the total velocity of the joint as compared with the barbell bench press. The horizontal velocity ranged from -.33m /s to .89m/s. This partly accounts for an increased overall maximum velocity from .81m/s in the barbell exercise to 1.34m/s in the dumbbell motion. This maximum velocity occurred while the weight was being raised.