At events and workshops the question always comes up as to whether a traditional barbell is not sufficient. There are numerous posts on social media under “Chaotic Training” and other keywords where the classic barbell is loaded with rubber bands and weight. But: does that really work?! NO! Anyone who takes the Earthquake Bar into their hands will immediately notice the huge difference!
These excerpts from studies provide information on a scientific basis!
Image: Motion of a Traditional Barbell with Stable Load(left) and of the Earthquake Bar with Unstable Load (right) (Stephanie J Ostrowski, Lara A Carlson, Michael A Lawrence, 2017)
Azar (2016) compared the Earthquake Bar (EQB) to a traditional weight-loaded barbell (SU)* kettlebells on elastic bands. He found that the EQB had significantly more muscle activation during the bench press and overhead press . In addition, the EQB was able to Under the same load intensity, the shoulder stabilizers are activated more strongly than the conventional dumbbell (SU) . In addition, the EQB shows a significantly higher mean value of EMG amplitudes in all muscle groups during both exercises (Azar, 2016).
The result of this study is that the EQB produced a significantly better interaction of muscle contraction than a conventional barbell . An ideal co-contraction index has an EMG amplitude ratio of 1.0, agonist to antagonist (Baratta, R., Solomonow, M., Zhou, H., Letson, D., Chuinard, R., & D'Ambrosia, R ., 1988) (Emily, G., 2015) (Kellis, E., Arabatzi, F. & Papadopoulos, C., 2003). Azar emphasized that the EQB maintained tension in the body throughout the lift by providing unpredictable forces.
Therefore, the EMG amplitude for agonist muscles decreases while that for the antagonist muscles increases . This leads to a much more ideal co-contraction ratio compared to a traditional barbell (Azar, 2016).
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Martin et al. (2020) designed an experiment that used a within-subject comparison between three different conditions:
1) Standard barbell and plate weights [SS],
2) Standard barbell with kettlebells suspended from the bar with 1/2 inch bands [SU],and
3) the Earthquake Bar with kettlebells suspended with 1/2 inch bands [EQ].
Although the major muscles showed no difference in activation, activities in other muscle groups such as shoulder and trunk stabilizers were increased in the EQ condition . Furthermore, the SU state only increases the activation of the latissimus dorsi and erector spinae compared to the SS state. Furthermore, the EQ condition showed a strong increase in front-to-back CoP excursion. Even compared to the SU condition, the EQ condition still had the best effect on shoulder and trunk stabilizer muscle activity. Finally, from the measured CoP excursion, we could see that the EQ condition presented a greater challenge to the athletes' overall stability. The main finding of the study is that the EQ condition increased scapular stabilizer activity, CoP* excursion, and reported RPE values the most compared to the SS and SU conditions (Martin R. Williams Jr. 1, Dustin S. Hendricks, Michael J. Dannen, Andrea M Arnold, Michael A Lawrence, 2020).
Another physical feature of the EQBar is its thick handle.
This thicker handle allows more energy to be transferred through the muscles and reduces stress on bones and joints .
Additionally, the flexible nature of the EQBar allows the bar to flex during lifting, reducing the shear force caused by the movements (see Shear Force on a Barbell illustration). This design also helps reduce the risk of injury.
Reasons for the differences:
We can attribute the increase in muscle activation to the body's constant need to stabilize the load (Emily, G., 2015) (Kellis, E., Arabatzi, F. & Papadopoulos, C., 2003). A traditional barbell applies load along a linear trajectory, even when loaded with weights on elastic bands. However, the EQBar has a completely different characteristic. It has more degrees of freedom, making it more difficult to stabilize them and predict the direction of movement (see figure) (Behm, DG, Leonard, AM, Young, WB, Bonsey, AC, & MacKinnon, SN, 2005) (Dunnick, DD, Brown, LE, Coburn, JW, Lynn, SK, & Barillas, SR, 2015) (Kellis, E., Arabatzi, F., & Papadopoulos, C., 2003) (McBride, JM, Larkin, TR, Dayne, AM , Haines, TL & Kirby, TJ , 2010) (Nairn, BC, Sutherland, CA, & Drake, JDM, 2015).
Louie Simmons didn’t call it “chaotic training” for nothing.
*Legend:
SU=Stable Unstable condition.
CoP = Center of Pressure