Research Review: Differences in Hip Muscle Activation with Variations of a Resisted Sidestepping Exercise
By Jinny McGivern PT, DPT, Certified Yoga Instructor
Edited by Brent Brookbush DPT, PT, MS, PES, CES, CSCS, ACSM H/FS
Original Citation: Berry, J. W., Lee, T. S., Foley, H. D., & Lewis, C. L. (2015). Resisted Side Stepping: The Effect of Posture on Hip Abductor Muscle Activation. Journal of Orthopaedic & Sports Physical Therapy, 45(9), 675-682. ABSTRACT
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Why is this relevant?:
The hip abductors, as a group, are typically implicated as "weak/under-active" in individuals with a wide variety of core and lower extremity pathologies. While there are multiple muscles that contribute to hip abduction, the authors of this study, Berry et al. (2015), assert that hip abduction "weakness" may be interpreted as impairment in the strength of the Gluteus Medius (GMed) . They highlight that the compensatory movement pattern of excessive hip adduction and internal rotation (leading to medial knee tracking) during weight acceptance in stance, is consistent with weakness of the posterior portion of the GMed . They also point out that the Tensor Fascia Lata (TFL) may attempt to compensate for impairments in GMed strength, but that it may also reinforce this maladaptive movement pattern because of the TFL's contribution to internal rotation of the hip. This research provides key information about a commonly performed exercise, resisted side-stepping, and how it can be performed to optimize activation of the hip muscles to create more efficient lower extremity mechanics. No previous studies have compared the activation of GMed versus TFL when the exercise is performed in the squat position and straight leg position.
Study Summary
| Study Design | Descriptive study |
| Level of Evidence | VI - Evidence from a single descriptive study |
| Subject Demographics | Convenience sample of 24 individuals was recruited.
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| Outcome Measures | Each subject's hip abduction Max Voluntary Isometric contraction (MVIC) was determined via EMG recordings during a standard manual muscle test for hip abduction prior to sidestepping activity. This allowed for normalization of EMG data collected during sidestepping exercise. During the performance of 8 sidesteps in each direction (band around ankles), the following outcome measures were collected for both the stance and moving limbs, during two different conditions (squat (self-selected depth) and upright standing):
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| Results | EMG Data
Kinematic Data
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| Conclusions | The resisted side-stepping exercise most effectively activates the GMed and GMax of the stance limb. Performance of this activity in the squat position allows for greater gluteal muscle activity with less TFL activity when compared with the upright position. |
| Conclusions of the Researchers | During a resisted sidestepping activity, the hip abductors of the stance limb are more active than the abductors of the moving limb. Performing sidestepping in a squat posture increases the activity of the GMax & GMed and reduces the activity of the TFL when compared to sidestepping with an upright standing posture. Hip abduction excursion is greatest on the stance limb as compared to the moving limb. |
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Review & Commentary:
There were many strong components to the methodology of this research study. Their outcome measures included both kinematic analysis and observation of EMG activity of muscles commonly targeted with this exercise. This resulted in a visually observable relationship between joint angle and muscle activity that could be used for cuing during implementation of this exercise. There was appropriate skin preparation for the surface EMG data collection. The kinematic analysis incorporated 10 video cameras to provide multiple views for analysis. The authors standardized the step length for each sidestep, and randomized the order in which the squat versus upright conditions were tested. The authors report that they selected a resistance band strength appropriate to each subject to minimize fatigue across conditions. They stated that most participants performed the activity with a light band, whereas a few used a moderate strength band.
While this research had many strengths, there are also limitations. It would have been beneficial if the authors better defined "healthy" and provided information on the general level of activity of their subjects. This would have allowed the reader to better understand the characteristics of the sample, especially with regard to a sedentary versus active lifestyles. The individuals observed were all young and healthy; therefore, these results may not be generalizable to older or injured populations. The MVIC data was collected using standard manual muscle testing procedures, which despite have pre-established protocols and reliability, also include inherent subjectivity. It may have been helpful to use dynamometry to collect information about the force generated by each subject's abductors. This would have allowed them to compare the force generated to the muscle activity observed. The sidestepping exercise was performed with the resistance band around the subject's ankles. This is a long lever and may have resulted in compensations at the knee joint (via tibial external and internal rotation - a functional valgus). Future research should assess the differences in muscle activation, comparing the band around the ankles, to the band just above the knees. Finally, it would have been interesting if the authors had reported on any dynamic knee valgus moments noted during the kinematic analysis, and when during the exercise these moments occurred. Because strengthening of the GMed is often performed to correct this maladaptive movement pattern, it would be useful to note when the knee is most vulnerable to this compemsatory motion.
The authors hypothesize that the reason for the increased TFL activity during the performance of the sidestepping exercise with an upright posture may be related to the TFL's role in balancing the trunk on top of the pelvis. Berry et al. (2015) point out that when upright the TFL helps to counterbalance the hip extension moment created by the gluteals firing. In the squat position, the hip flexion moment is created by gravity, thus reducing the need for TFL activation and allowing increased activity of the gluteals.
It is interesting to note that although variations in the activity of the gluteals and TFL were observed under the two different conditions, the TFL maintained a relatively higher percentage of activation than the gluteals during all variations of this exercise. The differences in activation indicate that when compared to the upright posture, the squat results in relatively reduced TFL activation and increased Gluteal activation, thus narrowing the gap. It is possible that if an individual reports that they are "really feeling" the front of their hip, this may not be the most ideal exercise to start them with. Further, it would be interesting to see the cuing used during the study and whether the subjects were attempting to push from the contralateral leg (ideal), versus reach with the ipsilateral leg. See below for more information about how the Brookbush Institute sequences exercises for the GMed .
Why is this study important?
This study is important because it reveals the specific differences in motor strategies during variations of a commonly performed exercise. This empowers human movement professionals to select the variation of this activity to meet the needs and goals of their specific client.
How does it affect practice?
This research provides support for a specific variation of the resisted side-stepping exercise to allow a more optimal activation ratio of GMax and GMed versus TFL . It highlights that there are many variables that influence which muscles are activated during a given movement or exercise - with alignment and posture being two of them.
It is interesting to note, that of the two limbs the stance limb is the more challenged limb with respect to both hip abduction excursion and muscular activation of the hip abductor group. This reminds us as human movement professionals that it would be advisable to assess hip abduction range of motion prior to prescribing this exercise for strengthening. The increased activity of the TFL throughout all variations also implies that we may need to reconsider the use of this exercise if our patient is not getting optimal results.
How does it relate to Brookbush Institute Content?
This research supports the Brookbush Institute's approach to cueing and sequencing exercises to get efficient training of the GMed to optimize lower extremity mechanics. The videos below detail where in an integrated warm-up sequence that the sidestepping exercise is most likely to be effective. The video sequence begins with static release and stretching techniques to decrease neural drive to the TFL , followed by isolated activation techniques for the GMed to promote increased neural drive ("priming" it for action). The basic side-stepping exercise follows these activities to integrate the GMed into larger human movement patterns. Following the basic variation of this exercise, (which is very similar to the exercise performed in this research) there are several additional videos with options for advanced progressions of sidestepping. The video below titled "Gluteus Medius Progressions (Activation Circuit)" details several strategies for dealing with a "stubborn" TFL .
The Brookbush Institute prefers to instruct individuals to perform this exercise in a slight squat (with a long spine), and focuses on cueing a push from the stance leg as opposed to a lifting forward of the moving leg. This research confirms that the stance leg is the limb with increased activity, therefore this approach to cueing reinforces that motor strategy.
The relationships between the GMed and TFL , and the occurrence of GMed weakness is discussed in two of the predictive models of postural dysfunction, Lower Leg Dysfunction and Lumbo-pelvic Hip Complex Dysfunction, and Sacroiliac Joint Dysfunction . The sidestepping exercise examined in this research is mentioned in interventions for both dysfunctions, for use by any program designed to rehabilitate or improve the performance of the core and lower extremity.
Tensor Fascia Lata (TFL) SA Static Release
Kneeling Hip Flexor SA Static Stretch
Gluteus Medius Progressions (Activation Circuit)
Side Stepping Gluteus Medius Reactive Activation
Side Stepping Progressions - Gluteus Medius Reactive Activation
Side-Stepping - Another Progression (Gluteus Medius Reactive Integration/Activation)
© 2015 Brent Brookbush
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