Bridging is one of those movements that shows up in multiple systems, with multiple variations, for differing reasons. There is the post rehabilitation bridge, designed specifically to work hip extension, the yoga bridge, which emphasizes opening up the front of the body, and the Pilates bridge, which focuses on vertebral segmentation. There is the Cook hip lift, the handstand to bridge in yoga, and the interesting CST bridge involving arm reaches and rotation, which I have only been exposed to once and in no way have mastered. All of these movements share the basic premise of hip extension and, when done incorrectly, can lead to either compression of the lumbar vertebrae or hamstring cramping/discomfort due to moving from the wrong place. Today, I am focusing on the latter, although I would argue that learning how to activate the gluteal musculature not only takes pressure off the hamstrings, but also allows the lumbar region to stay stable during hip extension.
The two main muscles involved in hip extension are the gluteus maximus (GM) and the hamstrings muscle group, specifically the long head of the biceps femoris (BF) and the semimembranosis (SM) (Ono, Higashihara, and Fukubayashi, 2011). In an ideal world, the gluteus maximus would be the prime mover, or main muscle used, and the BF and SM would be synergists, or muscles that help the gluteus maximus do its job. Unfortunately, what happens often in a culture where we spend a lot of time sitting and is these muscles become, in the words of the wise Sarah Young, "lazy." As a result, the BF and the SM pick up the slack, and take over as the prime mover. Why is this bad? Unlike the gluteus maximus, the BF and the SM aren't designed to generate large amounts of force. In a case study of a 42 year old triathlete complaining of hamstring cramping, EMG analysis showed excessive hamstring activation during hip extension and GM weakness (Wagner, Behnia, Ancheta, Shen, Farrokhi, and Powers, 2010). A hip strengthening program focusing on GM activation got rid of the cramping and increased GM strength. I would argue that an even greater issue with the hamstrings becoming the prime mover is an increased risk of hamstring avulsion. If the BF and SM are responsible for generating force repeatedly throughout the day, during standing up from a chair, running, and walking up stairs, eventually the wear and tear on the muscle will take its toll. Research needs to be done in this area to support this hypothesis, but I know I can think of three people off the top of my head who have either strained their hamstrings or experienced a rupture.
What does this have to do with bridging? It is important when learning how to bridge and teaching bridging to make sure the hip extension is initiated with the gluteus maximus. For the sake of this blog, I am going to focus on a post-rehabilitation bridge with the ultimate goal being something like the Cook hip lift or some other version of the single leg bridge, although both yoga and Pilates have their own tricks for ensuring proper activation patterns. I find having the person perform the exercise barefoot helps with GM activation. There has been surprisingly little (or no) research done on the effects of barefoot training versus shod training on GM activation, so this is purely anecdotal. The feedback from the floor and the focus on big toe activation seems to help the person find the right area. Another part of neuromuscular retraining which I find useful is visualization. Livesay and Samaras (1998) reported a significant increase in forearm EMG activity in subjects who were asked to visualize squeezing a ball with their dominant forearm. I have individuals focus on planting the foot firmly and evenly into the ground, using the big toe, pinkie toe, and heel to evenly distribute the weight. Then, I have the person imagine the GM, or butt, is doing the work to lift the hips on the ground. I have the person think about this while taking 3-5 deep, diaphragmatic breaths, maintaining that sense of grounding with the feet. After breathing and visualizing, I ask the person to lift up, extending (not squeezing) at the hips. I am looking for a straight line between the knees, hips, and shoulders. I make sure there is no compression at the cervical spine and that the lumbar spine stays in a neutral position, not arching. The person holds for a count of 5 and lowers down, repeating 10-15 times. Once the person has mastered this, it is time to progress to alternating bridges, which involves moving the feet all of the way together, placing the hands on the hip bones to make sure they stay even, and picking up one foot, and then the other. There should be no hip rotation and, if the foot and GM are integrated properly, there should be no cramping in the hamstring. The final progression is the single leg bridge, which can be done by starting in the same position and lifting the right leg off of the ground, the Michael Boyle version, which involves putting a tennis ball between in the hip flexor crevice of the right hip flexor and holding it there, or the Gray Cook way, which involves placing the hands around the shin of the right leg while lifting up. Everything else remains the same, and it is extremely important to maintain good contact with the ground with the left foot, focusing on extension of the left hip.
And, for the final question, why do we work on bridging? Hypothetically, if we can master hip extension in a supine position, it should make it easier to transfer the concept of hip extension while standing during movements such as squatting, walking, running, and stepping. These movements should be initiated with the GM and assisted by the BF and the SM, not the other way around. Remember: maintaining proper movement patterns allows you to move better and hopefully move more.
Yours in health and wellness,
Ono, T., Higashihara, A., & Fukubayashi, T., (2011). Hamstring functions during hip-extension exercise assessed with electromyography and magnetic resonance imaging. Research in Sports Medicine, 19(1), pp. 42-52.
Wagner, T., Behnia, N., Ancheta, W.K., Shen, R., Farrokhi, S., & Powers, C.M., (2010). Strengthening and neuromuscular reeducation of the gluteus maximus in a triathlete with exercise-associated cramping of the hamstrings. Journal of Orthopedic and Sports Physical Therapy, 40(2), pp. 112-119.
Livesay, J.R., & Samaras, M.R., (1998). Covert neuromuscular activity of the dominant forearm during visualization of a motor task. Perceptual Motor Skills, 86(2), pp. 371-374.