Don't Burn Your Bridges!

The supine bridge is a popular exercise. Whether you’ve been to physical therapy before or participated in personal training, chances are you’ve had some exposure to this exercise. The bridge is a great way to target most of the postural extension group together as one unit.

If you’re reading this article, your brain may think similarly to mine. Details matter. Especially in the world of exercise prescription, getting the correct exercise to the right person requires due diligence. This article describes how small changes to a single exercise can completely alter which muscles are being activated and to what degree. This is one of several reasons why I refrain from offering universal exercise recommendations without having evaluated someone.

With a basic bridge, activation of the quads, hamstrings, glutes, and spine extensors all work together, one full-body movement to achieve a simple, stable form. The list of secondary contributing muscles is high as well. Because of the orientation to gravity, resistance increases as the hips rise, which is the opposite of other similar exercises performed in standing.

No matter your athletic ability or stage in life, some form of the bridge has a place in your workout routine. I’ve used variations of this exercise in the clinic with young and old, athletic and nonathletic, runners, even a nationally-ranked power-lifter. For best results, know what your goal is and how the variations differ from one another. Not all bridges are created equal. Exercise should serve a purpose.

Standard Bridge: Low Back and Hip Extensors

Let’s start here. A standard bridge starts with knees bent slightly more than 90 degrees and feet/knees about 6-inches apart. If you raise your hips high enough, you can form a straight line from knee to shoulder that intersects the hip. This brings the hip joint angle to zero degrees, a neutral angle achieved in standing.

Supine Bridge

The standard bridge has good activation of both the large powerful spine erectors, as well as the deep spine stabilizers. It also has good potential to active these groups with relatively little change in spine curvature. This means you are training the lumbar spine in stabilization rather than movement.

Foot position will alter muscle activation at the hips to some degree. Largely, the hamstrings and glute max are contributing about equally to extend the hip to neutral. The quads will fire as well, mostly as stabilizers of the knee joints, without loading intensity high enough to elicit a significant strengthening response.

Hamstrings Bridge

From a standard bridge position, as the feet get further from the butt, the hamstrings become more heavily activated. This results in relatively less glute max activation in proportion. Because the lever arm has increased, the lumbar spine activation also increases. As the feet move farther out, you eventually end up completely flat with no where to go, so it’s common for them to also be elevated.

The hamstrings are a biarticular muscle, which means they cross 2 joints: the hip joint and knee joint. This means this muscle has the capacity to move both. In this exercise, the knees are largely static, hamstrings moving mostly the hip angle. The knee angle should not changes more than a few degrees. Arms can assist with balance or effort as needed.

Hamstrings bridge

The hamstrings bridge is similar to the Romanian dead lift mechanically speaking. Because the body is oriented to gravity differently, the loading gets more difficult at the top of the lift, which is opposite the dead lift which gets easier as you stand taller. With that in mind, this bridge has better potential to target those last 30 degrees of hip extension strength that the dead lift can.

Of note: these are also a great go-to exercise for insertional hamstring tendinopathy, as you are able to achieve high levels of tensile loading of the hamstrings tendons, without the rotational compression at the ischial tuberosity. This makes it a better option than a seated hamstring curl, when the tissue is easily irritated, at early in recovery.

Glute Max Bridge

Electromyography (EMG) studies have shown that glute max is most activated during hip extension from 70-90 degrees of hip flexion angle, which is more akin to sitting in a kitchen chair (and rising 4-6 inches) than the bridge position. Other studies show that by flexing the knee maximally while bridging, thus making the hamstrings mechanically insufficient, glute max activation increases to a meaningful degree.

As above but opposite, this creates a shorter level, which means that lumbar spine activation is lower, as confirmed in EMG studies. This is why this variation can be useful in persons trying to strengthen their gluteal hip extension while avoiding aggravation of lumbar spine pain.

As aesthetic glute max development is truly “all the rage” right now in pop fitness culture, variations of this exercise are popular. The one that comes to mind involves supporting the shoulders and trunk on a workout bench, while bringing the hips down to the floor. This exercise is typically referred to as a hip thrust. I think it’s apropos for this post.

This variation allows for a greater hip angle at the lowest point and less intrinsic resistance at the top from tightness in the quads. The spine curvature is more dynamic than the one I described previously, which could theoretically promote more hyperlordosis or back arching in a back squat/overhead squat activity.

This variation allows for easier addition of weight by loading at the hip joints. This is simply more limited in the floor version.

Clam shell Bridge with band

This bridge combines a clam shell movement with hip extension. Both of these things can be achieved by glute max largely, but by different physiological regions of the muscle. Functionally this is a great movement development tool in teaching athletes to extend the hip or “push-off” from a neutral to externally rotated position. This is a necessity for athletes with excessive dynamic knee valgus and associated pain.

Running propulsion is a complex subject. Similar with data from squat studies, powerful hip extension is the result of heavy force production from glute max, which extends and abducts the limb, and adductor magnus which extends and adducts the limb.

Band Bridge Up.jpg

There is notable contribution from quads and hamstrings as well, but if adductor magnus and glute max are not balanced out, the long term result can include increased scissoring, crossover gait, and dynamic knee valgus. This movement pattern plays a roll in at least a half dozens of the most common running related pain issues in my patients.

Single Leg Bridge Varieties

Any of the above described bridges can be gently transitioned to a single leg variety as the simplest next step of progression. It’s important to not compromise range of motion when doing so. I’ll address two varieties specifically, considerations, and rationale as to why it may make since for you.

The standard bridge variation transitions well to a single leg variety, with the only major change moving the weight bearing leg more toward the mid-line a couple inches. This a natural loading response whether in single leg stance standing still or mid-sprint: the foot shifts to a centered position to some degree.

Single Leg Bridge with Straight Leg Raise

As the pelvis rises, there is now double the load in hip extension on hamstrings and glutes, but profoundly more loading in the hip rotational stabilizers. These muscles were significantly less active in the double leg version. This is a great exercise for developing internal rotation strength in the glute medius and glute minimus in a closed-chain fashion.

The opposite leg position is variable, but should be placed in a position that doesn’t overload the system. Bringing the leg directly over the pelvis will be the easiest position. Maintaining the limb in neutral (as pictured above) will create additional rotational loading in the hip, so control and form must come first before moving to this version.

SIngle Leg Bridge

The hamstrings bridge is also another great variation to progress to a single leg variety. This is at the top of my list for runners who need to develop hip extension strength. Hip extension in running is always performed in single leg stance, hence strengthening interventions should eventually be performed at this level. Watching it be performed will also reveal other significant weaknesses that couple be contributing.

SIngle Leg Hamstrings Bridge .jpg

Final Thoughts

Good form and control are the best predictors of a successful exercise. These must come first. Always start with easy-moderate effort until the movement is learned well, especially before you transition to heavy loading. Some of these variations may be too difficult at first. If you need help, see a qualified human movement expert for help in determining updates in your fitness program.

Until next time, don’t stop moving!

-Allan

*Special thanks to my youngest son Gavin, who served as my chief photographer for this post.

*Special thanks to my youngest son Gavin, who served as my chief photographer for this post.