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Tuesday, June 6, 2023

Core Muscle Activity During Exercise in Quadruped Position

Brent Brookbush

Brent Brookbush


Research Review: Electromyographic Activity of Trunk and Hip Muscles During Stabilization Exercises in Four-point Kneeling in Healthy Volunteers

By Erik Korzen DC, NASM-CES, Acupuncturist

Edited by Brent Brookbush DPT, PT, COMT, MS, PES, CES, CSCS, ACSM H/FS

Original Citation: Stevens, V.K., Vleeming, A., Bouche, KG., Mahieu, N.N., Vanderstraeten, G.G., Danneels, L.A. Electromyograhpic activity of trunk and hip muscles during stabilization exercises in four-point kneeling in healthy volunteers. European Spine Journal, 2007. 16: 711-718. Full Article

Why is this relevant?: Core stabilization exercises are routinely utilized in clinical and athletic settings to aid in optimizing motion, force production and potentially reducing the risk of injury. The four-point kneeling position, also known as as the "quadruped position," is a starting position for many trunk stabilization exercises. This position lowers the center of mass, increases the base of support, while using the abdominal viscera to resist the drawing-in maneuver. In this study, the researchers monitored muscle activity via electromyography (EMG) during 3 exercises done in quadruped position. The results of this study imply trunk and extremity muscles work in synergy, specifically the highest muscle activity was noted in the ipsilateral multifidus lumborum and gluteus maximus muscles during all 3 exercise variations. This study adds to a significant body of research on trunk and extremity muscle activity during stabilization exercises (2-9).

Four-point kneeling (Quadruped) position as pictured above is the starting position used in this study.

Study Summary

Study DesignExperimental Study
Level of EvidenceLevel of Evidence IIB: Evidence from quasi-experimental study
Subject Demographics30 human subjects
  • 15 males, 15 females
  • Average age 19.6 years
  • Average height 176.6cm
  • Average weight 66.9kg
  • all participants had no experience with stabilization exercises
  • Exclusion Criteria: Subjects were excluded if they reported any past or current low back pain, current neurologic deficits, and/or pain or disability of the upper or lower limbs.
Outcome MeasuresMethods:
  • Subjects positioned in four-point kneeling position
  • Surface EMG sensors placed on the following muscles:

  • MVIC (maximum voluntary isometric contraction) was determined prior to testing to establish baseline measurements for EMG
  • 3 experimental exercises performed in random sequence from the four-point (quadruped) kneeling position, the 3 exercises are:
    • Exercise 1: quadruped position with single leg lift to horizontal
    • Exercise 2: quadruped position with single leg lift in addition to contralateral arm lift to horizontal
    • Exercise 3: quadruped position with single leg lift in addition to contralateral arm lift to horizontal while stabilizing leg has 30° of hip flexion

  • Dynamic portion of the exercises all lasted approximately 2 seconds while the static positions were held for 5 seconds
  • 3 trials performed for every exercise and at least 15 second pause between trials
  • Starting positions for all exercises were determined via sagittal plane by use of 2 lines connecting lumbar spinous processes (L1-3 and L3-5)
  • Relative EMG levels were calculated and categorized:

High activity >20% MVIC

Moderate activity  10-20% MVIC

 Low activity <10% MVIC


"Ipsilateral" and "contralateral" relative to hip motion.

Muscles demonstrating HIGH relative activity during specified exercises:

Muscles demonstrating MODERATE relative activity during specified exercises:

Muscles demonstrating LOW relative activity during specified exercises:


The contraction of the ipsilateral gluteus maximus and lumbar mutlifidus muscles were shown to have HIGH (>20% MVIC) relative muscle activity during ALL exercise in four-point kneeling.  There is also a HIGH (>20% MVIC) relative activity level of the contralateral internal oblique and ipsilateral external oblique during exercises 1 and 2.

Recruitment patterns of the ipsilateral lumbar portion of iliocostalis lumborum together with the contralateral thoracic portion of iliocostalis lumborum are recognized, indicating a cooperation between spine muscles.

The contralateral external oblique and bilateral latissimus dorsi show moderate (10-20% MVIC) relative activity levels during ALL exercises.  In addition, this study showed that extension of the upper extremity does not seem to influence latissimus dorsi activity.

In exercise 3,  the additional 30° of hip flexion position that seems to decrease abdominal muscle activity.

Conclusions of the Researchers

In a group of healthy subjects performing four-point kneeling exercises, it would appear that the investigated muscles work together harmoniously.

Based on relative muscle activity, no single muscle appears to enhance spine stability more than others.  The current study clearly utilizes the common spine-stabilizing position of four-point kneeling; therefore, the information may not be extrapolated to erect posture.

A point worth noting is that many of the muscle investigated in this study are invest in the thoracolumbar fascia, which is positioned to transfer force/tension from the trunk to the extremities.

This study clearly demonstrates that no single muscle is responsible for spine stabilization during four-point kneeling exercise, in a healthy population.  This study provides data regarding "normal" recruitment patterns in healthy subjects for comparison to symptomatic/impaired populations in future studies.

Illustration of the Posterior Oblique Subsystem with Muscles Labeled
Caption: Illustration of the Posterior Oblique Subsystem with Muscles Labeled

Posterior Oblique Subsystem


This study adds to a significant body of research on trunk and extremity muscle activity during stabilization exercises (2-9), and had many strong features. The authors developed a research methodology that analyzed and compared the activity of several muscles during 3 commonly used variations of a popular exercise. This allowed for a better understanding of how muscles are recruited in synergy; demonstrating that no single muscle was responsible for "core stabilization" during exercise performed in quadruped. Further, the progressions of the quadruped used in the study are commonly used in rehab, fitness and performance settings, adding to the practicality/relevance of this research. Separating muscle recruitment into high, moderate and low EMG activity groups, aided in the interpretation of data. For example, high muscle activity was observed for the ipsilateral (side of moving hip) lumbar mult ifidus and gluteus maximus during all 3 exercises tested, implying a strong synergistic relationship. Further, the contralateral internal oblique and ipsilateral external oblique showed relatively high levels of activity during exercises 1 and 2, along with moderate activity of both latissimus dorsi and the contralateral external oblique . Again, the inclusion of so many muscles, and the separation into groups based on activity, implies a strong tendency toward synergistic recruitment, and a potential relationship between stabilization of the spine and muscles investing in the thoracolumbar fascia . It is also evident that both local and global muscles function to stabilize the spine in this exercise, which may imply a need to re-examine this categorization. Last, the participants in this study were a homogenous, healthy group of individuals without a history of low back pain or extremity issues. The data collected during this study may serve as a baseline for comparison to participants with low back pain or extremity issues.

This study had a few weakness. EMG timing data was not provided. Some studies have shown that the timing of muscle recruitment may be as related to dysfunction as the relative amount of activity (2, 4, 10). Surface EMG was used, which may result in less accurate muscle activity data due to cross-talk and altered surface impedance, although significant effort was placed in using methods that have shown high validity. Further, the use of surface EMG did not allow for analysis of deep muscles, such as the transverse abdominis , rotatores or quadratus lumborum - to fully understand the recruitment of muscle synergies, all muscles should be accounted for. Although the homogeneous group of participants may create a good baseline for comparison in future studies, it does create issues when attempting to apply this information to a rehab population. Additionally, future research should incorporate more movements from the four-point kneeling position and relate findings to a more functional or erect position; perhaps, alterations in muscle activity during functional tasks after performing several sets of quadruped exercise.

Why is this study important?

This study ads in-vivo data to support several anatomic studies that suggest a complex integrated network of myofascial structures (11). Knowledge of the distinct actions of individual muscles is essential for analysis of the human movement system; however, understanding that muscles are recruited as part of myofascial synergies is likely more accurate relative to function. Based on this study, stabilization of the spine during most variations of the quadruped exercise requires high activity form the ipsilateral (side of moving hip) lumbar mult ifidus and gluteus maximus, the contralateral internal oblique and ipsilateral external oblique , along with moderate activity of both latissimus dorsi and the contralateral external oblique .

How does this affect practice:

This study provides evidence of synergistic recruitment of both global and intrinsic stabilizing muscles during the quadruped exercise. This should be considered when the quadruped is integrated into rehab, fitness and performance training programs. For example, lumbar pathology resulting in lumbar mult ifidus atrophy may benefit from ipsilateral hip extension patterns to enhance recruitment. For more on core muscles synergies, the following reading is recommended: intrinsic stabilization subsystem , posterior oblique subsytem , anterior oblique subsystem, lateral subsystem deep longitudinal subsystem.

How does it relate to Brookbush Institute Content?

The Brookbush Institute predictive models of lumbopelvic-hip complex dysfunction (LPHCD) , lumbosacral dysfunction (SIJD) , upper body dysfunction (UBD) and lower body dysfunction (LLD) may ALL be affected by, or potentially relate to abnormalities in movement and core muscle synergy recruitment. Comprehensive assessment of functional movements would include dynamic posture/movement assessment (Overhead Squat Assessment) , as well as assessment of the hip , sacroiliac joint, shoulder complex, lumbar and thoracic spine. A conceptual framework for integrating the findings of this study into practice may be found in the Brookbush Institute's discussion on core subsystems, specifically the posterior oblique subsystem (POS) and intrinsic stabilization subsystem (ISS) . The videos below are examples of "Quadruped" variations, which may also be found in the article "Transverse Abdominis (Intrinsic Stabilization Subsystem) Activation ":

Transverse Abdominis Activation:

Dynamic Quadruped:

Hardest Quadruped Variation EVER!


  1. Stevens, V.K., Vleeming, A., Bouche, KG., Mahieu, N.N., Vanderstraeten, G.G., Danneels, L.A. Electromyograhpic activity of trunk and hip muscles during stabilization exercises in four-point kneeling in healthy volunteers. European Spine Journal, 2007. 16: 711-718.
  2. Hodges, P., Richardson, C. (1996). Inefficient Muscular Stabilization of the Lumbar Spine Associated With Low Back Pain: A Motor Control Evaluation of Transverse Abdominis. Spine, 21(22), 2640-2650.
  3. Hodges, P. & Richardson C. Feedforward contraction of transversus abdominis is not influenced by the direction of arm movement C. Exp Brain Res (1997) 114: 362. doi:10.1007/PL00005644
  4. Richardson, C., Snijders, C., Hides, J., Damen, L., Pas, M., Storm, J. (2002) The Relation Between the Transversus Abdominis Muscles, Sacroiliac Joint Mechanics, and Low Back Pain. Spine. 27 (4), 399-405 .
  5. Hides, J. A., Richardson, C. A., & Jull, G. A. (1996). Multifidus Muscle Recovery Is Not Automatic After Resolution of Acute, First‐Episode Low Back Pain.Spine, 21(23), 2763-2769.
  6. Hides, J. A., Jull, G. A., & Richardson, C. A. (2001). Long-term effects of specific stabilizing exercises for first-episode low back pain. Spine, 26(11), e243-e248.
  7. Grenier, S., McGill, S. (2007). Quantification of lumbar stability by using 2 different abdominal activation strategies. Archives of Physical Medicine & Rehabilitation. 88, 54-62 .
  8. Sihawong, R., Janwantanakul, P., Jiamjarasrasi, W. (2014) A prospective, cluster-randomized controlled trial of exercise program to prevent low back pain in office workers. European Spine Journal 23:786-793
  9. O’Sullivan PB, Phyty GD, Twomey LT, Allison GT. (1997). Evaluation of specific stabilizing exercise in treatment of chronic low back pain with radiologic diagnosis of spondylolysis or spondylolisthesis. Spine. 22(24): 2959-2967.
  10. Bullock-Saxton, J. E. (1994). Local sensation changes and altered hip muscle function following severe ankle sprain. Physical therapy74(1), 17-28
  11. Willard, F.H., Vleeming, A., Schuenke, M.D., Danneels, L., Schleip, R. The thoracolumbar fascia: anatomy, function and clinical considerations. Journal of Anatomy, 2012. 221, 507-536

© 2016 Brent Brookbush

Questions, comments, and criticisms are welcomed and encouraged -