The glute bridge and hip thrust are exercises that are often used in an effort to strengthen the gluteus for squats. They are also used in the rehabilitation world for “inactive” glutes.
The aim of this article is to break the functional mechanics of the bridge in relation to squats, and explain how it is possible to train the bridge, and yet you cannot engage the gluteus during squats.
(From now on, I will use the “bridge” to cover the use of both the glute bridge and the hip thrust).
How muscles work
Before we analyze squat and bridge, we need to start with principles that allow us to understand how muscles function in an isolated exercise such as a bridge in relation to the complex squat movement.
“The bridge has high EMG activity; therefore it should teach our glutes to work when we perform a more functional, complex squat. So why doesn’t it happen? ”
Much of the science of exercise is about strengthening muscles in an isolated way. This isolated method is based on concentric muscle contraction that shortens and creates movement. In the case of a bridge, the gluteus contracts concentrically to produce a hip extension.
In the article, the so-called The science of hip and gluteus suppression, Bret Contreras discussed the science of maximal gluteus activation, including a study of the optimal amount of hip and knee flexion required for the largest EMG readings. The purpose of this article is not to question its methods, as they are accurate for the function and purpose for which they are used – maximum gluteal contraction for maximum hypertrophic gains. Instead, this article will show how the bridge is not correct for improving gluteus function in our squat goal.
The glute bridge was reportedly further developed using knee straps for pushing (hip abduction) and toe rotation (external rotation). The theory is that performing all three concentric actions of the gluteus muscles simultaneously (extension, abduction, external rotation) will ensure maximum EMG activity of the gluteus.
“Conscious muscle contractions come from isolated movements, but during functional (multi-joint) movement it is impossible to tell every muscle to work.”
A high EMG reading is considered of great importance in terms of how good exercise is in recruiting muscle. The bridge has high EMG activity; therefore it should teach our glutes to work when we perform a more functional, complex squat.
So why doesn’t that happen?
How the body works
In the bridge, you don’t learn to squat gluteus, you just stretch your hip. The bridge works in a supine position face up, with the nervous system as good as sleeping. Associate this with prolonged rest in bed, where muscles atrophy and people become weaker because we have lost the fight against gravity, which stimulates constant activation of low-level muscles.
When we lie down, we no longer fight gravity. This means that the nervous system throughout the body is activated little or not at all. So when the hips are raised, the only neurological drive goes to the gluteus, hence the high EMG reading for the bridge.
When we stand under a load ready to squat, the amount of pressure experienced by the entire nervous system is greater than the pressure of the bridge. As we begin to descend and the hips move toward the floor, neurological activity goes to every muscle in the body. As we squat, all the muscles inside the hips contract and lengthen at different times, learning how to work as a team to overcome both gravity and the load that travels with momentum.
This is one of the key factors why the gluteus bridge does not seem switch to squat. The body works as one complete system, with a large neurological conversation taking place between the muscles to accomplish the task. When we perform the gluteus bridge, the gluteus learns to work in isolation, and there is little conversation with neighboring muscular friends. Consequently, when we get up and perform a squat, the glutes no longer know when to contract compared to other muscles that work during complex squats.
“When we build the gluteus bridge, the gluteus learns to work in isolation, and there is little conversation with neighboring muscular friends.”
The nervous system works subconsciously to control all human movements. Conscious muscle contractions come from isolated movements, but during functional (multi-joint) movement it is impossible to tell every muscle to work. You cannot select a sequence of muscle start patterns because more than one muscle is working. It is impossible to consciously control the complexity of that sequence. Even if you could control the order, you would be so distracted from the task at hand that you would probably fail anyway.
How mechanics work
Muscle sequence is not the only contrasting factor, the mechanics are also different. In the bridge, the gluteus starts from the point of no activity and then shortens. The gluteus has stored energy, but there is no cycle of stretching and shortening as in squats.
During the lower squat phase, the gluteus moves through hip flexion, adduction (begins in a relatively abducted position, but continues to move inward as you squat), and internal rotation. This is the natural mechanics of squatting.
The joint mechanics of the knee is flexion and internal rotation, so the internally rotating femur occurs in the eccentric squat phase. Keep in mind, I’m not saying knees kiss. If the knee crosses over the foot, then it is the internal rotation of the hip.
The downward phase creates an extension of the gluteus in all three planes of movement (hip flexion in the sagittal plane, hip adduction in the frontal plane, and internal rotation in the transverse plane). This process of lengthening creates an elastic load that allows the gluteus to expand explosively and concentrically, abducting and external rotation of the hip, allowing us to stand.
“[L]The simulated range of motion means that the gluteus is not learning what to do in the hole at the bottom of the squat, and that is when we really need the gluteus to help us. ”
The above joint movements are not replicated during the bridge, as there is no shortening of the stretch due to the limited range of motion within which the bridge is performed. One effect of the bridge is gluteus tightness, which means that the gluteus can contract only in a shortened range of motion and not in a large range of motion such as squats. This limited range of motion means that the gluteus is not learning what to do in the hole at the bottom of the squat, and that is when we really need the gluteus to help us.
Enter the Lunge
To truly help activate the gluteus, the exercise closest to squatting is a step forward. Hip joint movements are almost identical – hip flexion, internal rotation and adduction when lowering the movement, allowing the gluteus to work through its cycle of stretching and shortening. However, there is little difference between squats and jumps. In the stride we have the force of reaction of the ground as the foot strikes the floor, so the mechanics are not completely identical because the squat has a load pattern from top to bottom.
But in the breakthrough, the gluteus learns how to work with all the other hip muscles in a coordinated and synchronized sequence of movements. The angles of the joints are similar to those in the squat (on the front leg) and, importantly, the ankle, knee and spine also learn how to move the hips through that movement. In the bridge, only the hip is moved and stretched, with the ankle and spine in a completely different position and under a different stress than in the squat, so the correct pattern of movement and muscle sequence is not learned.
“In the bridge, only the hip moves and stretches, and the ankle and spine are in a completely different position and under a different stress than in the squat.”
The stride also allows each leg to work independently and become strong on its own. I have not yet evaluated a squat that is 100% balanced. We all have a leg that is stronger and that we prefer when squatting. We must try to balance the system.
So go ahead and jump out! But thirty steps is not enough to create the desired changes in the recruitment of the motor pattern. The second part of this article will deal with the programming required for significant changes in your motor patterns.
You will also find these articles interesting:
1. Contreras, B. “The science of hip and gluteus suppression. ” Glute Guy. Last modified April 6, 2013
2. Worrell TW., Et al. “Influence of joint position on electromyography and moment generation during maximal voluntary isometric contractions of knee tendon and gluteus maximus muscle. ” J Orthop Sports Phys Ther. 2001. December; 31 (12): 730-40.
Photo 1 courtesyShutterstock.
Photographs 2, 3 and 4 courtesyCrossFit Empirical.