by Bret Contreras June 24, 2011
Here’s a study that’s fresh off the press. In fact, it was just posted online around one hour ago. How’s that for fast service on my part? The study compared the straight bar deadlift to the hex bar deadlift.
Many coaches (including myself) have theorized that the trap bar deadlift allows lifters to:
1. Lift more weight
2. Place less loading on the spine, and
3. Get more knee extensor involvement
These findings were all shown to be true in a brand new study by Swinton et al. (2011) titled A Biomechanical Analysis of Straight and Hexagonal Barbell Deadlifts Using Submaximal Loads. Here is the abstract:
Swinton, PA, Stewart, A, Agouris, I, Keogh, JWL, and Lloyd, R. A biomechanical analysis of straight and hexagonal barbell deadlifts using submaximal loads. J Strength Cond Res 25(7): 2000-2009, 2011—The purpose of the investigation was to compare the kinematics and kinetics of the deadlift performed with 2 distinct barbells across a range of submaximal loads. Nineteen male powerlifters performed the deadlift with a conventional straight barbell and a hexagonal barbell that allowed the lifter to stand within its frame. Subjects performed trials at maximum speed with loads of 10, 20, 30, 40, 50, 60, 70, and 80% of their predetermined 1-repetition maximum (1RM). Inverse dynamics and spatial tracking of the external resistance were used to quantify kinematic and kinetic variables. Subjects were able to lift a heavier 1RM load in the hexagonal barbell deadlift (HBD) than the straight barbell deadlift (SBD) (265 ± 41 kg vs. 245 ± 39 kg, p < 0.05). The design of the hexagonal barbell significantly altered the resistance moment at the joints analyzed (p < 0.05), resulting in lower peak moments at the lumbar spine, hip, and ankle (p < 0.05) and an increased peak moment at the knee (p < 0.05). Maximum peak power values of 4,388 ± 713 and 4,872 ± 636 W were obtained for the SBD and HBD, respectively (p < 0.05). Across the submaximal loads, significantly greater peak force, peak velocity and peak power values were produced during the HBD compared to during the SBD (p < 0.05). The results demonstrate that the choice of barbell used to perform the deadlift has a significant effect on a range of kinematic and kinetic variables. The enhanced mechanical stimulus obtained with the hexagonal barbell suggests that in general the HBD is a more effective exercise than the SBD.
It should be mentioned that subjects were allowed to rise up onto their toes at the end of the movement in order to facilitate more acceleration through the exercises. What was very surprising is the amount of peak power that occurred in the submaximal deadlifts. Previous work by Escamilla et al. 2000 showed that elite powerlifters took 4 seconds to complete the concentric portion of the rep, which equated to only .2 m/s of velocity. And since power equals force x velocity, despite the large forces seen in the max deadlift, power output is not very impressive. Here’s an excerpt from the article discussing the peak power output:
In the current investigation, peak power for the SBD and HBD reached 4,388 and 4,872 W, respectively, with individual values as high as 6,049 and 6,145W recorded. Studies quantifying power during Olympic weightlifting exercises have reported maximum peak power values similar to those obtained here. Winchester et al. (33) and Cormie et al. (6) reported maximum peak power values of 4,230 and 4,900 W, respectively, for college athletes performing the power clean.
One issue I have with using traditional strength exercises for the purpose of power production is the fact that the barbell must be decelerated toward the top of the movement. The researchers mentioned this in their article:
Some researchers have asserted that performing traditional resistance exercises with submaximal loads is an ineffective method for developing muscular power (25). This position is based on previous studies reporting extended periods of deceleration and reduced force production to slow the barbell velocity to zero at the end of the movement (8,25)
The researchers go on to say:
The results from this study show that even with very light loads the majority of the exercise duration can be used to accelerate the load (Table 4).
In looking at the table around 60% of the lift was spent accelerating the load with a 10% 1RM load, which climbed up to over 80% for the 80% 1RM loads.
For practical advice, the authors stated:
If the training objective is to target the lumbar area and maximally recruit the erector spinae muscles then it is recommended that the SBD is performed. Because the HBD more evenly distributes the load between the joints of the body, practitioners may find deadlifts performed with the hexagonal barbell to be an effective alternative to the squat and an appropriate exercise to use in the final stages of low back rehabilitation.
In addition, they mentioned that:
This is the first study to demonstrate that the deadlift can be combined with submaximal loads to generate large power outputs. The finding suggests it may be advantageous to include the deadlift in structured periodized models aimed at developing muscular power. The results of the study also demonstrate that the HBD can produce significantly greater peak force, peak velocity, and peak power values than the SBD. Strength and conditioning coaches should be aware of the enhanced mechanical stimulus created with the hexagonal barbell when selecting a deadlift exercise.
1. The hex bar deadlift is clearly the safer lift as it reduces the moment on the lumbar spine.
2. That said, it also reduces the moment on the hip joint (while increasing the moment on the knee and ankle joints).
3. As I mentioned in my Topics of the Week article that I linked above, I still prefer the conventional deadlift because I use the full squat as my knee dominant exercise so I want a deadlift variation that complements the full squat and acts more on the hips.
4. Although the peak power levels are very impressive for the submaximal deadlifts (where you rise up onto the toes), you still spend a large percentage of the time decelerating the load which means reduced muscular tension through end range hip extension (though 87% of the 80% 1RM deadilft was indeed spent accelerating, so only the last 13% of end range hip extension is spent decelerating).
5. For this reason elastic bands could be used to increase tension on the hip extensors toward end range hip extension.
6. For this reason I like the jump squat and hang clean (or even the trap bar jump and possibly the deadlift plus shrug/calf raise) as I don’t believe they’d involve any deceleration at the top of the lift (though I confess that I haven’t located studies that address this issue…but nonetheless studies addressing this likely exist).
Check out this video from Joe DeFranco…scroll to :42 seconds into the video and you can see an example of trap bar jumps.
Whenever I watch a DeFranco video I get all jacked up and want to train!
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