Hip Abduction Increased Glute Max Activation in Bridging Exercise

• • • Age: 21.6 ± 1.6 years (Age, Standard Deviation)
    • Gender: 10 M, 10 F
    • Height (cm) - 169.3 ± 7.7
    • Weight (kg) - 62.4 ± 10.6
    • BMI (kg/m²) - 21.5 ± 3.2
    • Characteristics:
      • Protocol
        • Surface electromyography on gluteus maximus and erector spinae
          • Data collected from dominant kicking leg
          • Erector spinae - electrode placed 2 cm away from the spine at the level of the iliac crest
          • Gluteus maximus - electrode placed at half the distance from the greater trochanter to the second sacral vertebrae at an oblique angle

        • Pelvic Tilt Angle Surface Markers
          • One marker placed on the anterior superior iliac spine and one on the posterior superior iliac spine of the dominant kicking leg
          • Bridging exercise was recorded at 1.2 meters from the participant and transferred to a software program to determine pelvic tilt angle
            • Pelvic tilt angle - defined as the angle between the line connecting the anterior superior iliac spine and the posterior superior iliac spine and the vertical line from the anterior superior iliac spine

        • Maximum Voluntary Isometric Contraction (MVIC)
          • Performed on gluteus maximus and erector spinae to normalize muscle activation data as a percentage of MVIC according to Kendall et al. (2) testing positions

        • Bridging Exercise
          • Prior to data collection, each participant practiced the bridging exercise for 5 minutes
          • Participant positioned on his/her back with knees bent to 90° with feet at hip width's apart and arms crossed over the chest
          • Hip abduction angle defined by angle of the mid-line of the patella and the anterior superior iliac spine
          • Two plastic poles positioned lateral to both legs to prevent compensatory motion
          • Wooden target bar positioned to ensure equal height of pelvic lifting for each trial
            • Target was set as the height of the thigh when the shoulders, hips, and knees were aligned in a straight line during bridging

          • Participants instructed to lift pelvis off the table at a self-selected speed, touch the wooden target, and hold the position for 5 seconds while maintaining slight contact with the poles on the lateral aspect of the knee
            • Data discarded when compensation was observed (excessive contact with poles)
            • Middle 3 seconds were recorded for data

          • Each participant performed 3 bridges per abduction position with a 30-second inter-trial period and 2-minute break in-between each condition
          • Order of bridging positions was randomized by computer-based randomization program to minimize internal validity concerns

        • Statistical Analysis
          • One-way ANOVA performed to compare muscle activity with anterior pelvic tilt angle with each of the three abduction angles
          • Intra-rater reliability conducted on EMG amplitudes of gluteus maximus and erector spinae and anterior pelvic tilt angle

• Inclusion Criteria: N/A
• Exclusion Criteria:
  • A history of lumbar, sacroiliac, or lower limb injury within the past year
  • Past or present neurological, musculoskeletal, and/or cardiopulmonary disease
  • Hip flexor shortness (by the Thomas Test)
  • Adductor muscle shortness (by Adduction Contracture Test)
  • Lumbar or hip pain when performing bridging exercise

• • • Gluteus Maximus and Erector Spinae Activity and anterior pelvic tilt angle in 0°, 15°, and 30° of hip abduction
    • Gluteus Maximus/Erector Spinae EMG Ratio at 0°, 15°, and 30° of hip abduction.

¹ = Electromyography

² = Mean ± standard deviation

³ = p < 0.05

ConclusionsGluteus maximus activity in the bridge increases as hip abduction angle increases from 0° to 30° while erector spinae activity and anterior pelvic tilt angle show the reverse patternConclusions of the ResearchersPerforming the bridge exercise in increasing amounts of abduction can minimize compensatory erector spinae firing and facilitate gluteus maximus recruitment and better pelvic tilt angle

Caption: Illustration of the Posterior Oblique Subsystem with Muscles Labeled

Posterior Oblique Subsystem

Review & Commentary:

The current study exhibited strength in its simple methodology. The authors sought to determine whether or not increases in hip abduction in the bridge exercise would increase gluteus maximus activation and reduce activity of overactive synergists, as was shown in a previous study (1). The sample population was 20 healthy individuals without history of any musculoskeletal pathology. The surface electromyography implemented in the protocol was standardized and placed on musculature that is superficial (which is ideal for this type of instrumentation), minimizing the chance of cross-talk from other neighboring muscles. Individuals in this study performed 3 repetitions of bridges in 3 different (randomly assigned) degrees of hip abduction with equipment in place to minimize compensatory movements (wooden blocks to ensure adequate range of motion and plastic poles to reduce excessive knee movement). Participants held hip extended position for 5 seconds while data was collected, further the position was assessed by two different practitioners to improve reliability.

While the study's strength lie in its simplicity, there are some limitations that must be addressed before integration into practice. First, the authors did not measure both sides of the body, even though the bridging exercise is bilateral in nature. This could lead to biased results as the study only measured dominant side (as indicated by which leg the individual reported kicking a soccer ball with). Second, no measurement of the abdominal musculature was taken. This is an important limitation as bracing the abdominal muscles is commonly prescribed prior to elevation of the pelvis. Last, the current study was conducted on healthy participants so it is unknown whether or not the current trends would be present in pathological populations.

Why is this study important?

The bridge is a common exercise used by human movement professionals to facilitate gluteus maximus activity. In the position the bridge is commonly performed (0° of hip abduction, feet positioned hip-to-shoulder width apart), the activity of other muscles can produce compensatory movement patterns. These compensations may include an excessive anterior pelvic tilt, biceps femoris over-activity (1), and increased activity of the erector spinae - reinforcing compensation patterns. The current study may support performing the bridge exercise in 30° of hip abduction to diminish the synergistic activity of erector spinae and reduce the likelihood of adopting an the anterior pelvic tilt. Note further research is needed to determine if hip abducted bridges increase activity of other synergists, including the adductor magnus , piriformis and deep rotators of the hip .

How does it affect practice?

The current study supports performing bridging in 30º of hip abduction to reduce synergistic dominance of the erector spinae and promote better pelvic alignment. Previous investigations into promoting increased gluteus maximus activation looked into prone hip extension at 30° of hip abduction and found as hip abduction increased, reduction in the activity of biceps femoris was observed (1). The authors hypothesized that due to the fiber arrangement of the gluteus maximus (angled from superomedial to inferolateral approximately 32-45°), hip abduction aligns more gluteus maximus fibers with the direction of pull. Increased abduction also seems to decrease the activity of the biceps femoris and erector spinae resulting in a relative increase in gluteus maximus activity.

Gluteus maximus strengthening may be performed at hip abduction angles greater than 0° to facilitate activation. The authors did note however, that above 30° of hip abduction, participants reported discomfort. When incorporating bridging into an exercise regimen, human movement professionals should determine the appropriate amount of hip abduction on a case-by-case basis based on comfort and the movement impairment the client/patient exhibits.

Gluteus maximus activity during the 30° of hip abduction condition reached a %MVIC of 20.34%, so integrating other exercises for gluteus maximus strengthening is also indicated. Exercise modifications to increase the %MVIC of the gluteus maximus during the bridge exercise include addition of external loads and/or use of theraband around the knees.

How does it relate to Brookbush Institute Content?

The gluteus maximus muscle is commonly classified as "long/underactive" in many of the postural dysfunction models proposed by the Brookbush Institute. As such, gluteus maximus activation exercise is commonly indicated. The current study supports the Brookbush Institute's approach to gluteus maximus strengthening by performing activation exercises with varying degrees of hip abduction to decrease activity of overactive synergists (biceps femoris ; and now, erector spinae ). Further, the bridge can be used to integrate the posterior oblique subsystem and strengthen the core to enhance intermuscular coordination during functional tasks and exercise.

The bridging exercise performed in this study had participants cross their arms across their chest, which is the 3rd progression off of the bridge exercise series . The Brookbush Institute provides further instructions to aid in the reduction of overactive synergists by using the following positional adjustments and/or verbal cues when performing the bridge:

• Biceps Femoris Dominance – (“I feel it in my hamstrings”) – As part of the deep longitudinal subsystem the biceps femoris may become overactive in individuals with SI joint dyskinesis and/or a weak glute complex. Correcting this dysfunction should include biceps femoris release and lengthening prior to exercise, a decrease in the angle of the knee to shorten the hamstrings and render them "actively insufficient", and cuing the client to push their hips up with their butt – not push the body backwards or forwards with the quads and/or hamstrings. Note: Dorsiflexion, inversion, and tibia internal rotation may also disengage the biceps femoris but careful attention must be given to recruitment of the adductor complex during this modification.
• Erector Spinae/Lat Dominance – (“I feel it in my lower back”) – Dysfunction of the posterior oblique subsystem often results in gluteus maximus inhibition, latissimus dorsi overactivity, and an anterior pelvic tilt. An APT will quickly lead to adaptive shortening of the erector spinae  and over-acitivity. A simple child’s pose stretch before exercise and cueing rectus abdominis bracing should correct LPHC position and the relative length of gluteus maximus . This should result in an increase in gluteus maximus recruitment and a decrease in low back discomfort.
• Post Fibers of Adductor Magnus dominance – (“I feel it in my inner thighs") – Generally this is accompanied by a posterior pelvic tilt during the exercise, and may also include external rotation and mild abduction of the knees. Release and lengthening of the posterior fibers of the adductor magnus and gluteus medius activation should be done prir to exercise, and careful cuing should focus on a correcting pelvic position and knee alignment.
• Psoas/TFL Dominance – (“I can’t get any higher”) – Generally this results in a reduction in hip extension range of motion, and may be accompanied by external rotation and abduction of the femur. Release and lengthening of the hip flexors should be done prior to exercise."

The following videos are related to gluteus maximus manual muscle testing and strengthening using the bridging exercise and its progressions.

Brookbush Institute Videos

Gluteus Maximus MMT For An Active Population

Gluteus Maximus Isolated Activation

Glute Activation Circuit

Ball Bridge

Static Ball Bridge with Trunk Rotation:

Dynamic Ball Bridge with Trunk Rotation:

Dynamic Ball Bridge with Trunk Rotation from Brent Brookbush.

© 2016 Brent Brookbush

Questions, comments, and criticisms are welcomed and encouraged -

References:

1. Suehiro T, Mizutani M, Ishida H, et al. (2015). Effect of abduction and external rotation of the hip joint on muscle onset time during prone hip extension with knee flexion. J Phys Ther Sci. 27(1): 289-291.
2. Florence Peterson Kendall, Elizabeth Kendall McCreary, Patricia Geise Provance, Mary McIntyre Rodgers, William Anthony Romani, Muscles: Testing and Function with Posture and Pain: Fifth Edition © 2005 Lippincott Williams & Wilkins