Research Review: Posterior Muscle Chain Activity during Extension Exercises
By Erik Korzen DC, NASM-CES, Certified Acupuncturist
Edited by Brent Brookbush DPT, PT, COMT, MS, PES, CES, CSCS, ACSM H/FS
Original Citation: DeRiddler E., Oosterwijck, J., Vleeming, A., Vanderstraeten, G., Danneels, L. (2013). Posterior muscle chain activity during various extension exercises: an observational study. BMC Musculoskeletal Disorders, 14: 204. Full Article
Why is this relevant?: Understanding the function of myofascial synergies and their contribution to movement and stability of the skeletal system, may have implications for exercise and intervention selection in rehab, fitness and performance settings. The specific muscles and fascial structures that comprise these myofascial synergies, specifically along the posterior chain, is area of continued study and debate. In this study, the activity of the thoracic and lumbar extensors, as well as the gluteal muscles were examined during various exercises. The researchers utilized surface EMG (electromyography) during 4 distinct exercises: dynamic trunk extension, dynamic-static trunk extension, dynamic leg extension and dynamic-static leg extension. The findings of this study imply that motion of either the trunk or lower extremity has more influence on muscle recruitment than the type of contraction performed.
Trunk Extension exercise position
Study Summary
| Study Design | Case Control Study |
| Level of Evidence | VI - Evidence from a single descriptive or qualitative study |
| Subject Demographics | 14 healthy subjects (6 females, 8 males)
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| Outcome Measures | sEMG (surface electromyography) recordings during randomized sequencing of:
Participants performed a repetition maximum for each exercise. The repetition maximum represents the maximum number of repetitions performed before fatigue prohibits completion of an additional repetition. This measure was used to determine the relative intensity of the exercise. This was followed by 2 sessions of standardized repetitions at 60% maximum, with at least 2 days between sessions. Exercise intensity was calculated using the following formula: (Upper/Lower body weight ) x Exercise load ) _________________________________________ Exercise load determined on testing day This calculation determined if participants received assistance (-) or an adjustment (+). The maximal voluntary contraction (MVC) was measured 3 times for 4 seconds with 30 seconds of rest between each trial. All tests were performed in the prone position. The starting position: trunk 45 degrees below horizontal and legs 45 degrees below horizontal for trunk and leg exercises. Dynamic Trunk Extension Legs strapped to a table, a repetition consisted of 2 seconds of raising the trunk from the starting position and 2 seconds of lowering to starting position. Dynamic-Static Trunk Extension with legs strapped to a table. A repetition consisted of 2 seconds of raising the trunk from starting position, a 5 second hold at horizontal and 2 seconds of lower to starting position. Dynamic Leg Extension with the trunk strapped to a table. A repetition consisted of 2 seconds of raising the legs from the starting position and 2 seconds of lowering to starting position. Dynamic-Static Trunk Extension with the trunk strapped to a table. 1 repetition consisted of 2 seconds of raising the legs from starting position, a 5 second hold at horizontal and 2 seconds of lower to starting position. Borg Scale Following each exercise, participants assessed the intensity of the exercise via verbal Borg scale scores.
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| Results |
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| Conclusions | The Latissimus Dorsi and Gluteus Maximus muscles were recruited less during all exercise when compared to paraspinal muscles. There was a higher contribution of the lumbar and thoracic muscles during trunk extension exercises than during leg extension exercise. This study demonstrated lumbar muscle activity was higher during trunk extension than during leg extension. The type of contraction (dynamic or isometric) does not affect posterior muscle chain recruitment patterns. |
| Conclusions of the Researchers | The results demonstrated that recruitment of the posterior muscle chain during extension exercises at 60% 1-RM was influenced by the body part that was extended, but not by the type of contraction (dynamic or dynamic-static). To improve the endurance capacity of the Longissimus thoracis pars thoracic and Iliocostalis lumborum pars thoracis muscles all four types of extension exercises could be used. In clinical practice, therapists can use leg extension to ameliorate lumbar muscle endurance, whereas trunk extension exercises can be used to specifically activate the lumbar muscles and enhance their strength and endurance (70% 1-RM). The Latissimus Dorsi and Gluteus Maximus muscles were activated to a lesser degree during all exercises, which may imply that other exercises should be used to increase the endurance capacity of these muscles. |
Leg Extension exercise position
Review & Commentary:
There were many strong components to the methodology used in this study. The authors obtained 14 healthy, young subjects for this study with a mean age of 24.7 years. The authors utilized commonly performed posterior chain exercises to examine the myo-electric activity of various muscles. The researchers used 60% of the 1 repetition maximum for each subject as well as a randomized order of the 4 exercises to standardize the testing. Additionally, the comparison of dynamic vs dynamic-static muscular contractions allows movement professionals to assess the use of isometric contractions during exercises aimed at posterior chain strength and endurance. Furthermore, the use of the Borg exertion scale added valuable subject feedback for the various exercises performed.
In a previous study conducted by Plamondon et al. (1) , the authors concluded that "no differences were observed between the two different types of extension exercise regarding activity of the erector spinae (ES), the multifidus (LM), and the gluteus maximus (GM)". However, the current study adds the evaluation of thoracic muscles, and found differences between the two criteria. The exclusion criteria of the current study ensured that low back pain, spinal deformities and/or spinal surgeries did not confound findings. This study adds to an established body of research regarding the use of extension exercises to activate various muscles along the posterior chain. This includes the following studies: Back muscle fatigue during intermittent prone back extension exercise , Electromyographic activity of the trunk extensor muscles: Effect of varying hip position and lumbar posture during Roman chair exercise and Electromyographic amplitude and frequency changes in the iliocostalis lumborum and multifidus muscles during a trunk holding test (1-3).
This research also had limitations. The current study had subjects perform 5 repetitions of each exercise which may have been insufficient to activate the gluteus maximus muscle. Previous studies indicate that the gluteus maximus may be activated during later repetitions of a set of trunk extension (1). The placement of the sEMG sensors, although very detailed, proves to be a difficult task due to the overlapping layers of muscles in the posterior chain. The anatomical and functional distinction of the paraspinal muscles is complex, as many studies suggest that these muscles do not function as a singular mass. Therefore, the placement of the sEMG sensors could result in inaccurate data collection. The data obtained from this study is in relation to a group of healthy subjects and would be considered "normal". This is advantageous for human movement professionals as it provides a model of muscle recruitment for normal individuals; however, further research is needed on how pain and dysfunction may alter muscle recruitment. Last, considering the participant positioning and equipment used, minor variations in position and direction of force may have occurred that may have altered recruitment patterns and influenced results.
Why is this study important?
This study provides additional evidence to support the use of extension exercises to activate lumbar extensors. It also indicates that the erector spinae group is activated to a higher degree during trunk extension than they are during leg extension and that the type of contraction is irrelevant for the recruitment of posterior chain muscles. Surprisingly, the latissimus dorsi and gluteus maximus muscles were found to be fairly inactive throughout the 4 extension exercises used in this study. This finding implies that other exercises should be performed if the desired effect is to recruit these two muscles.
How does it affect practice?
While it is important to employ various exercises to recruit muscles of the posterior chain, this study provides evidence of how a specific group of exercises recruits specific muscles of the posterior chain. Based on the findings of this study, extension type exercises may be appropriate for recruiting lumbar extensors , but would be less effective for recruiting the latissimus dorsi , gluteus maximus and the posterior oblique subsystem . Application of this information may include the avoidance of trunk extension exercises, if the goal of intervention is to reduce activity of the erector spinae muscles and increase posterior oblique subsystem recruitment. Further, this study demonstrates that muscle recruitment is related to exercise selection, more than the type of contraction being emphasized during the movement.
How does it relate to Brookbush Institute Content?
The recruitment of muscles in the posterior chain via extension exercises is a modality widely used in rehabilitation, fitness and performance settings. The Overhead Squat Assessment and Manual Muscle Testing may be used for assessment of function and strength of the muscles in this study. Finding from this study may imply that during extension type exercise that the Deep Longitudinal Subsystem (DLS) is dominant, and the Posterior Oblique Subsystem (POS) is not effectively recruited. The joint dysfunction and muscle imbalances described in the predictive models of postural dysfunction - Lower Leg Dysfunction (LLD) and Lumbopelvic Hip Complex Dysfunction (LPHD) describe alterations in activity of the muscles in this study, as well as the relative activity of the POS and DLS . Based on these models and the research that has lead to their development, in conjunction with the findings of this study, back extension type exercises would be contraindicated, and more focus should be given to movement patterns that increase glute activation and posterior oblique subsystem integration.
The videos below demonstrate useful assessment procedures as well as activation and integration techniques for specific muscles.
Gluteus Maximus Manual Muscle Test (MMT) for an Active Population:
Gluteus Maximus Activation:
Quick Glute Activation Circuit:
Glute Reactive Activation:
Posterior Oblique Subsystem Integration:
Glute Complex Kinesiology Taping:
Bibliography:
- Plamondon, A., Trimble, K., Larivière, C. and Desjardins, P. (2004), Back muscle fatigue during intermittent prone back extension exercise. Scandinavian Journal of Medicine & Science in Sports, 14: 221–230. doi: 10.1111/j.1600-0838.2004.00363
- Mayer JM, Verna JL, Manini TM, Mooney V, Graves JE.Electromyographic activity of the trunk extensor muscles: effect of varying hip position and lumbar posture during Roman chair exercise. Arch Phys Med Rehabil. 2002 Nov;83(11):1543-6.
- Ng JK1, Richardson CA, Jull GA. Electromyographic amplitude and frequency changes in the iliocostalis lumborum and multifidus muscles during a trunk holding test. Phys Ther. 1997 Sep;77(9):954-61.
© 2016 Brent Brookbush
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