A common deadlift cue is to ‘wedge’ your hips to the bar. I’ve heard a theory stemming from this cue that bringing the hips closer to the bar will reduce the amount of force experienced at the hips, supposedly making the lift more efficient. To put simply – Bringing hips closer to the bar = less force at hips = less force required to lift a barbell from point A to Point B.
Sounds cool, but it doesn’t make sense.
Work = Force X Distance
70kg X 9.81 (gravity) = 687 Newtons (Force)
687 Newtons X 0.725metres = 498 Joules (Work)
So, we can say 498 joules of energy from my body was required to move a 70kg weight by 72.5cm. I probably used more energy than this to move the barbell as energy conservation is not 100% efficient; A lot will be lost as heat. Regardless, 498 joules of energy is still transferred from my body to the barbell to move the barbell.
In the wedge technique and the static hip start, the distance the barbell travelled was the same in both deadlift styles. As such, would have used approx. the same amount of energy to displace the barbell. Efficiency differs between deadlift styles when comparing a sumo to conventional deadlift. Escamilla et al. (2000) found on average vertical barbell displacement was 35.3cm ± 5.7 in the sumo stance versus 44.4cm ± 5.7 in the conventional. This resulted in 25-30% less mechanical work when doing the sumo. As such, the sumo is a more efficient deadlift.
2. Like the above point, as the distance the barbell travelled did not change, the sum total of forces experienced at the body to lift the barbell off the floor would not have changed. The weight of the 70kg barbell is 687 Newtons. Meaning, I would have to generate a total of 688 newtons of force from my body to lift the barbell off the floor. The hips are not just generating force; we also must consider all the other muscles and joints contributing force to perform a deadlift.
These are arbitrary numbers and are being used just for clarity. Let’s say not bringing the hips close to the barbell requires 50% of force from the hip extensors and 50% of force from the leg extensors to lift the barbell off the floor. Wedging the hips closer to the barbell might reduce force contribution from the hip extensors to 40%. However, the leg extensors are now contributing 60% of the force to overcome the force of the barbell. So if bringing the hips closer to the bar reduces the amount of force experienced at the hips, there would have to be an increase in force from other muscles to make up that 688 newtons we need to lift the barbell off the floor.
As the demands from one muscle group go down, the other go up. As mentioned, the weight of the barbell has not changed. We still require the same total amount of force to lift the barbell off the floor. Force requirements would reduce if less work were being done (e.g. the distance the barbell travels decreases). But this is not the case, as explained earlier.
So does wedging make the deadlift more efficient? No. It probably just shifts focus on different muscles slightly. We would have to use 3-D video analysis to calculate joint moments and EMG to calculate muscle activation to know how much of a difference there is in muscle force contribution between wedging and non-wedging styles to see if there is even a significant difference between the two (no one actually knows if wedging does indeed reduce hip extensor demands as it has never been directly measured from my understanding).
If there is a difference, I would predict that the wedging style would reduce force demands placed on the hip extensors but increases the demands placed on the knee extensors. It’s like wedging is the ‘high bar’ version of the deadlift, and having the hips further away is like the ‘low bar’ version of the deadlift.
Does this mean we should not wedge? No. It is still a fine technique, and people should use it if they like it. But does wedging make the deadlift more efficient? No.