Abstract
Background
Hip extension is an important action in daily activities (standing, stepping and walking) and sporting actions (running, sprint-running and jumping). Though several different exercises exist, a comprehensive understanding of which exercises best target the gluteus maximus (Gmax) and the magnitude of muscular excitation associated with each exercise is yet to be established.
Purpose
The purpose of this systematic review was to describe the electromyographic (EMG) excitation of the Gmax during body weight exercises that utilize hip extension.
Methods
A systematic approach was used to search Pubmed, Sports Discuss, Web of Science and Science Direct using the Boolean phrases (gluteal OR gluteus maximus) AND (activity OR excitation OR activation) AND (electromyography OR EMG) AND (hip extension). Articles that examined injury-free participants of any age, gender or excitation level were included. Articles were excluded when not available in English, where studies did not normalize EMG excitation to maximum voluntary isometric contraction (MVIC), where a load or resistance was added to the exercise, or where no hip extension occurred. Exercises were grouped into vertical and horizontal (anteroposterior or posteroanterior) force vectors.
Results
Thirty-nine studies of high methodological quality were retained for analysis. Twenty-five exercises were performed in the vertical vector (average: 33.4% MVIC, highest: single leg wall squat 86% MVIC), fourteen exercises were performed in the horizontal (anteroposterior) force vector (average: 32.8% MVIC, highest: single leg bridge 54.2% MVIC, while thirty-eight exercises were included in the horizontal (posteroanterior) vector (average: 30.4% MVIC, highest: plank with bent leg hip extension 106.2% MVIC).
Limitations: The differences in subject's backgrounds, exercise technique and the methodological approaches varied between studies, most notably in the different positions used for obtaining MVIC, which could have dramatically impacted normalized levels of gluteal activation.
Conclusion
The findings from this review provide an indication of Gmax muscle excitation generated by a variety of hip extension body weight exercises, which may assist practitioners in making exercise selection decisions for programming.
Keywords: gluteal musculature, hip strengthening, force vector, EMG, movement system
INTRODUCTION
Hip extension is an important joint action in daily activities (standing, stepping and walking) and sporting actions (running, sprint-running and jumping). The hip extensor musculature are capable of producing the highest torque compared to any other muscle group involved in hip movement.1 Hip extension primarily involves the gluteus maximus (Gmax), hamstrings (long head of biceps femoris, semimembranosus, and semitendinosus), and posterior head of the adductor magnus.1,2 Recruitment of the Gmax and associated hip extensor muscles, coupled with efficient movement are required for optimal hip extension force production.3 Although several muscles contribute to hip extension, the focus for this article is on the Gmax musculature and its role in hip extension during body weight exercise.
Though several different exercise protocols exist, scientific evaluation of their specific effects on the Gmax has yet to establish which exercises best isolate the musculature and what level of muscular excitation is elicited. Electromyography (EMG) is a tool that provides insight into how the neuromuscular system behaves via amplitude information regarding the timing characteristics and muscle excitation levels for a given recording condition.4,5 Historically, exercises have been examined through EMG analysis with the general consensus assumed that exercises producing higher levels of muscular excitation are associated with greater long-term strength and size increases.6,7 Though debate remains about the application of EMG in a practical context 4 it is a commonly implemented method within the literature and therefore may be used as a guideline to assist in understanding musculature excitation.
Weakness and imbalanced strength in the Gmax is associated with multiple lower extremity injuries and lower back pain8 which can necessitate substitution by synergist musculature.9 Consequently, practitioners often choose to incorporate Gmax targeted exercise in both rehabilitation and sport settings by starting with unloaded (i.e. body weight only) exercises. An extensive variety of body weight hip extension exercises are used for training, both in athletic performance and in rehabilitation programming. As one alters the body's position during the different hip extension exercise options, this will result in a change in the amount of body mass being moved by the hip musculature and the orientation of the gravitational force-vector. Selecting exercises by taking into regard the direction of the force-vector 10,11 (i.e. horizontal vs vertical, Figure 1) may play an important role in developing different and specific functional adaptations.12 Moreover, specificity of movement promotes intermuscular coordination which has been shown to increase transference to sport performance.13 Therefore, classifying hip extension body weight exercises by the respective force vectors may be important for best exercise selection for activity type and conversion into performance outcomes.
Figure 1.
Force-vector directions occurring during a vertical exercise (i.e. vertical loading with respect to anatomical position, also known as an axial vector) and a horizontal exercise (i.e. horizontal loading with respect to anatomical position, also known as an anteroposterior vector). Horizontal oriented exercises can be further challenged by the direction of the horizontal loading from the opposite direction to anteroposterior, known as the posteroanterior vector.
It is important to take into consideration the force-vector associated with different exercises when developing programming for rehabilitation or performance enhancement as different force-vector exercises have been shown to elicit differences in Gmax EMG amplitudes. This was certainly the case in loaded hip extension exercises with equated 10 repetition maximum loads that resulted in a significant greater amount of mean lower and upper Gmax excitation found in the horizontal vector exercise (barbell hip thrust, 40.8-69.5% MVIC) compared to the vertical vector exercise (barbell back squat 14.9-29.4% MVIC).14 Similarly, Gmax excitation was 16% higher during the barbell hip thrust (horizontal) compared to the hex bar deadlift (vertical) with 1RM loading.15 Whether these differences occur in unloaded hip extension exercises is unknown. Therefore, the purpose and focus of this systematic review was to describe the EMG excitation of the Gmax during body weight exercises that utilize hip extension. Exercises were grouped by force vector position to assist practitioners in making decisions for exercise selection that targets Gmax excitation.
METHODS
Literature Search Strategies
The review was conducted in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) statement guidelines.16 A systematic search of the research literature was undertaken for studies that investigated EMG amplitude (given as mean %MVIC) for the Gmax in body weight exercises that utilised dynamic hip extension. Studies were found by searching Pubmed, Sports Discuss, Web of Science and Science Direct electronic databases from inception to November 1st 2017 using the following Boolean search phrases: (gluteal OR gluteus maximus) AND (activity OR activation) AND (electromyography OR EMG) AND (hip extension). Additional studies were also found by reviewing the reference lists from retrieved studies.
Inclusion and Exclusion Criteria
Articles that examined injury-free participants of any age, sex or activity level were included. No restrictions were imposed on publication date or publication status. Studies were limited to English language. Studies were excluded that did not normalize EMG excitation to %MVIC or did not present the results as numbers (i.e. results presented as figures). This review focussed on exercises performed without any additional load, therefore only body weight exercises were included and studies which contained an external load (e.g. barbell, dumbbell, band, and machine) were excluded. Plyometric or hopping movements were also excluded as they are performed with higher acceleration, therefore they have an advantage in terms of eliciting high levels of gluteal excitation. Moreover, plyometric exercises are higher end performance type exercises and should be used once an individual exhibits prerequisite strength levels (eccentric) which includes mobility and stability.
Study Selection
One reviewer (PM) searched the databases and selected studies. A second reviewer (EF) was available to assist with study eligibility. No disagreements about the appropriateness of an article were encountered. A search of electronic databases and a scan of article reference lists revealed 355 relevant studies, with an additional 14 studies found via hand searches of references lists (Figure 2). After removing duplicate studies (n = 68), screening titles (n = 78) and abstracts (n = 149), 49 studies were retained. Following full-text screening, a further 10 studies were excluded (6 studies were not normalised to MVIC, 4 studies reported results as figures), thereby, 39 studies were retained for this review.
Figure 2.
PRISMA diagram of article selection through the different phases of the systematic review.
Methodological Quality Score
Methodological quality was assessed using the quality index of Downs and Black17 modified version.18 A value of 0 or 1 was assigned to the different subcategories of the following items: reporting, external validity, and internal validity. A total score < 10/17 was considered to be low quality, while scores ≥ 10/17 were presumed to be high quality.18
RESULTS
Quality assessment scores of the thirty-nine articles included ranged from 10 to 14, with an average score of 11.6 out of 17, indicating a high methodological quality for the studies reviewed (Appendix 1). There were a total number of 938 subjects who performed 77 total exercise variations. Appendix 1 summarises all studies included. All studies used surface electrodes, with the exception of Selkowitz, Beneck, Powers 19 who used fine wire electrodes. Two studies19,20 reported the superior (upper) and inferior (lower) regions of the Gmax, while the remaining Gmax values were obtained from electrodes positioned on muscle belly (descriptions of electrode placement are given in Appendix 1). Results are presented within vertical and horizontal force vector tables with horizontal exercises further sub-divided into anteroposterior and posteroanterior due to high number of exercises within each sub-division). Results for the same exercise have been averaged from the combined totals to present a mean percentage of MVIC and mean range value for the exercise. However, due to differences between study methodologies caution should be used for interpreting the findings, therefore, the mean values should be interpreted as a guideline. Exercises were grouped by the magnitude of mean Gmax excitation and stratified into the four levels of activity: 0-20% MVIC was considered low muscle excitation, 21-40% MVIC was considered moderate muscle excitation, 41-60% MVIC was considered high muscle excitation, and greater than 60% MVIC was considered very high muscle excitation.21,22 This classification scheme provides a means by which the practitioner can select exercises, that match the capabilities of their client/athlete thus targeting neuromuscular, endurance, or strength type training, and provides a means by which the Gmax can be progressively overloaded in a systematic fashion. Table 4 provides a summary of average %MVIC for Gmax in the different force vector positions.
Table 4.
Summary of average %MVIC for Gluteus Maximus in different force vector positions. Values given as the mean and the standard deviation.
| Force vector position | Vertical | Horizontal | |
|---|---|---|---|
| Anteroposterior | Posteroanterior | ||
| Number of studies | 21 | 9 | 18 |
| Number of subjects | 534 | 255 | 363 |
| Number of exercises | 25 | 14 | 38 |
| Gmax average %MVIC | 33.4 | 32.8 | 30.4 |
| Gmax range %MVIC | 6.1-86.0 | 10.9-54.2 | 9.7-106.2 |
Gmax = Gluteus Maximus, MVIC = maximum voluntary isometric
Vertical force vector
The Gmax excitation for exercises performed in the vertical force vector can be found in Table 1. Twenty-five different exercises were performed in this force vector with the most common exercises being the single leg squat (9), lunge (7), and lateral step up (6). The highest mean excitation was found in the single leg wall squat with other leg knee extended (86 ± 43% MVIC) and the lowest activity occurred in the squat with 0 ° trunk flexion (6.1 ± 4.0% MVIC). Eight exercises were classified as low excitation, ten were moderate excitation, four were high excitation, and three were very high excitation. Of note, variations of the deadlift exercises were included in this force vector although the force vector is not truly vertical and crosses with the anteroposterior force vector.
Table 1.
Comparison of muscle excitation in the Gluteus Maximus for all vertical force vector exercises. Values given as the mean and the standard deviation.
| Classification level of %MVIC | Exercise | Number of studies | Number of subjects | Mean %MVIC of Gmax | Range % MVIC of Gmax |
|---|---|---|---|---|---|
| 0-20% | Squat with 0 ° trunk flexion58 | 1 | 20 | 6.1 ± 4.0 | Not available |
| Squat with 15 ° trunk flexion58 | 1 | 20 | 6.3 ± 4.0 | Not available | |
| Squat with 30 ° trunk flexion58 | 1 | 20 | 8.0 ± 4.9 | Not available | |
| Lunge with pelvic compression belt48 | 1 | 20 | 13.9 ± 7.7 | Not available | |
| Squat19,48,55, | 3 | 58 | 14.4 ± 4.3 | 10.5-21.7 | |
| Forward step up and over42 | 1 | 44 | 16.5 ± 11.7 | Not available | |
| Lateral step down28 | 1 | 34 | 16.5 | 8.4-24.6 | |
| Lunge with trunk extension41 | 1 | 10 | 19.3 ± 11.8 | Not available | |
| 21-40% | Lunge with trunk flexion41 | 1 | 10 | 22.3 ± 12.0 | Not available |
| Lunge19,31,41,43,42,44,48 | 7 | 185 | 22.8 ± 12.3 | 11-44 | |
| Forward step down28 | 1 | 34 | 23.1 | 19.0-27.2 | |
| Lateral lunge43,45 | 2 | 61 | 26.5 ± 14.5 | 12-41 | |
| Single leg wall squat, other leg knee flexed28 | 1 | 34 | 26.8 | 21.6-32.0 | |
| Single leg mini squat, other leg knee flexed24,28 | 2 | 57 | 34.6 ± 16.3 | 20.3-57 | |
| Single leg squat with pelvic compression belt48 | 1 | 20 | 35.5 ± 21.7 | Not available | |
| Lateral step up24,25,28,31,39,52 | 6 | 143 | 36.0 ± 17.8 | 16-63.8 | |
| Single leg deadlift with pelvic compression belt48 | 1 | 20 | 36.3 ± 21.9 | Not available | |
| Forward step up 19,24,25,28,44,52 | 6 | 119 | 38.7 ± 19.5 | 15.7-74 | |
| 41-60% | Single leg squat25,26,27,42,43,44,48,49,50 | 9 | 227 | 43.2 ± 14.9 | 18.9-81.2 |
| Single leg deadlift27,43,48 | 3 | 65 | 48.6 ± 14.6 | 27.9-59 | |
| Transverse lunge43 | 1 | 21 | 49 ± 20 | Not available | |
| Retro step up24 | 1 | 23 | 59 ± 35 | Not available | |
| >60% | Skater squat25 | 1 | 24 | 66.2 | Not available |
| Single leg squat with rotation49 | 1 | 9 | 78 ± 45 | Not available | |
| Single leg wall squat, other leg knee extended 24 | 1 | 23 | 86 ± 43 | Not available |
Gmax = Gluteus Maximus MVIC = maximum voluntary isometric contraction
Horizontal force vector (Anteroposterior)
Information regarding the Gmax excitation for the anteroposterior force vector can be observed in Table 2. Fourteen different exercises were performed in this force vector with the most common exercises being the single leg bridge (6) and two-legged bridge (6). The highest absolute excitation was found in the single leg bridge (54.2% MVIC), though when this exercise was averaged from six studies the mean activity was 39.9% MVIC. The lowest excitation occurred in the bridge with feet on a gymnastics ball exercise (13.0% MVIC). Four exercises were classed as low excitation, five were moderate excitation and five were high excitation.
Table 2.
Comparison of muscle excitation in the Gluteus Maximus for all anteroposterior force vector exercises. Values given as the mean and the standard deviation.
| Classification level of %MVIC | Exercise | Number of studies | Number of subjects | Mean %MVIC of Gmax | Range % MVIC of Gmax |
|---|---|---|---|---|---|
| 0-20% | Bridge with feet on a swiss ball and hamstring curl56 | 1 | 26 | 10.9 | Not available |
| Bridge with feet on a swiss ball56 | 1 | 26 | 13.0 | Not available | |
| Bridge with hamstring curl56 | 1 | 26 | 18.5 | Not available | |
| Bridge with knees extended and feet on a swiss ball56 | 1 | 59 | 20 ± 14 | Not available | |
| 21-40% | Bridge19, 29, 31, 40, 56, 57, | 6 | 177 | 23.3 ± 8.8 | 16.4-41.5 |
| Single leg bridge with foot on bosu56 | 1 | 26 | 28.4 | Not available | |
| Bridge with verbal and tactile cues29 | 1 | 15 | 33.0 | Not available | |
| Supine manual resisted hip extension2 | 1 | 26 | 34.7 | Not available | |
| Single leg bridge2,19,25,31,56,57 | 6 | 153 | 39.9 ± 7.6 | 32.6-54.2 | |
| 41-60% | Single leg bridge. DOM leg 135 ° knee flexion with dorsiflexed ankle. Non- DOM leg knee relaxed in flexion and femur vertical30 | 1 | 28 | 40.4 ± 24.6 | Not available |
| Single leg bridge. DOM leg 90 ° knee flexion with foot flat. Non-DOM leg knee relaxed in flexion and femur vertical30 | 1 | 28 | 47.2 ± 28.1 | Not available | |
| Single leg bridge. DOM leg 135 ° knee flexion with foot flat. Non- DOM leg knee extended30 | 1 | 28 | 47.4 ± 24.8 | Not available | |
| Single leg bridge. DOM leg 90 ° knee flexion with dorsiflexed ankle. Non- DOM leg knee relaxed in flexion and femur vertical30 | 1 | 28 | 49.1 ± 26.4 | Not available | |
| Single leg bridge. DOM leg 90 ° knee flexion with foot flat. Non-DOM leg knee extended30 | 1 | 28 | 51.0 ± 28.1 | Not available |
DOM = dominant Gmax = Gluteus Maximus MVIC = maximum voluntary isometric contraction
Horizontal force vector (Posteroanterior)
Information regarding the Gmax excitation for the posteroanterior force vector can be found in Table 3. Thirty-eight different exercises were performed in this force vector. The highest mean excitation was found in the plank with bent leg hip extension (106.2% MVIC) followed by prone hip extension with upper body on table and flexed contralateral knee joint on a chair (66.4 ± 25.8% MVIC). The lowest excitation occurred in the prone hip extension from hip flexion of 30 ° (9.7 ± 2.9% MVIC). Seven exercises were classed as low excitation, twenty-two were moderate excitation, seven were high excitation, and two were very high excitation.
Table 3.
Comparison of muscle excitation in the Gluteus Maximus for all posteroanterior force vector exercises. Values given as the mean and the standard deviation.
| Classification level of %MVIC | Exercise | Number of studies | Number of subjects | Mean %MVIC of Gmax | Range % MVIC of Gmax |
|---|---|---|---|---|---|
| 0-20% | Prone hip extension from 30 ° hip flexion to 10 ° hip extension46 | 1 | 16 | 10.9 ± 3.3 | Not available |
| Prone hip extension from 30 ° hip flexion with verbal cue to activate the hamstrings37 | 1 | 11 | 11.2 ± 5.2 | Not available | |
| Prone hip extension from 30 ° hip flexion33,37 | 2 | 36 | 14.4 ± 4.4 | 9.7-18.9 | |
| Prone hip extension up to 20 ° with 90 ° knee flexion20 | 1 | 20 | 15.9 ± 4.2 | 11.7-20.1 | |
| Prone hip extension with knee extension34,51 | 2 | 41 | 15.5 ± 2.8 | 12.7-18.3 | |
| Prone hip extension with 90 ° knee flexion and neutral hip position32,34 | 2 | 52 | 18.6 ± 4.5 | 14.1-23.1 | |
| Prone hip extension from 0 ° hip flexion33 | 1 | 15 | 19.7 ± 7.9 | Not available | |
| 21-40% | Prone hip extension with knee flexion with hip abducted 0 °8 | 1 | 30 | 20.2 ± 8.6 | Not available |
| Quadruped hip extension bent leg non-DOM25 | 1 | 24 | 21.0 | Not available | |
| Prone hip extension with lateral hip rotation and knee flexion34 | 1 | 31 | 21.2 ± 12.0 | Not available | |
| Prone hip extension from hip flexion of 30 ° with verbal cues to activate the glutes37 | 1 | 11 | 21.6 ± 9.8 | Not available | |
| Prone hip extension from 15 ° hip flexion33 | 1 | 15 | 22.5 ± 9.4 | Not available | |
| Prone hip extension with 90 ° knee flexion and 15 ° hip abduction32 | 1 | 21 | 22.5 ± 13.6 | Not available | |
| Prone hip extension with lateral hip rotation and knee extension34 | 1 | 31 | 22.5 ± 10.4 | Not available | |
| Prone hip extension with knee flexion with hip abducted 15 °8 | 1 | 30 | 23.4 ± 9.9 | Not available | |
| Prone hip extension to hip extension of 10 °54 | 1 | 15 | 23.9 ± 18.5 | Not available | |
| Prone hip extension to hip extension of 10 ° with abdominal drawing-in54 | 1 | 15 | 24.4 ± 14.3 | Not available | |
| Prone hip extension up to 20 ° with 90 ° knee flexion with abdominal bracing20 | 1 | 20 | 26.3 ± 9.7 | 16.6-36.0 | |
| Back extension with extended knees and hands behind head53 | 1 | 18 | 26.5 ± 13.6 | Not available | |
| Back extension with extended knees and hands across chest53 | 1 | 18 | 28.3 ± 14.5 | Not available | |
| Reverse hyperextension38,47 | 2 | 27 | 28.7 ± 7.3 | 20.3-38.8 | |
| Prone hip extension with knee flexion with hip abducted 30 °8 | 1 | 30 | 29.6 ± 11.5 | Not available | |
| Quadruped hip extension with knee extended19 | 1 | 20 | 29.9 ± 1.3 | 28.5-31.2 | |
| Prone back/torso extension38,47 | 2 | 27 | 31.8 ± 6.2 | 23.8-44.9 | |
| Quadruped hip extension with knee flexed19 | 1 | 20 | 32.2 ± 2.1 | 30.1-34.3 | |
| Prone hip extension to hip extension of 10 ° with pelvic tilt > 15 °54 | 1 | 15 | 32.5 ± 21.3 | Not available | |
| Back extension with flexed knees 90 ° and hands across chest53 | 1 | 18 | 34.8 ± 20.6 | Not available | |
| Back extension with flexed knees 90 ° and hands behind head53 | 1 | 18 | 36.6 ± 22.6 | Not available | |
| Reverse hyperextension with lumbopelvic control strategy38 | 1 | 13 | 38.8 ± 24.1 | Not available | |
| 41-60% | Prone hip extension with 90 ° knee flexion and 15 ° hip abduction and 20 ° hip external rotation32 | 1 | 21 | 41.0 ± 23.6 | Not available |
| Prone hip extension to hip extension of 10 ° with abdominal drawing-in with pelvic tilt > 15 °54 | 1 | 15 | 45.9 ± 33.7 | Not available | |
| Prone hip extension with upper body on table and abdominal drawing-in35 | 1 | 16 | 47.5 ± 19.8 | Not available | |
| Prone hip extension with upper body on table35,36 | 2 | 34 | 53.1 ± 9.2 | 43.9-62.3 | |
| Quadruped arm and leg raise31 | 1 | 30 | 56.2 ± 22 | Not available | |
| Prone hip extension with body on floor36 | 1 | 18 | 56.5 ± 20.2 | Not available | |
| Quadruped hip extension bent leg DOM25 | 1 | 24 | 59.7 | Not available | |
| >60% | Prone hip extension with upper body on table and flexed contralateral knee joint on a chair35 | 1 | 16 | 66.4 ± 25.8 | Not available |
| Plank with bent leg hip extension25 | 1 | 24 | 106.2 | Not available |
DOM = dominant Gmax = Gluteus Maximus MVIC = maximum voluntary isometric contraction
Summary of force vectors
Details of Gmax excitation for all positions are summarized in Table 4. The vertical position produced the highest average excitation (33.4% MVIC) followed by the anteroposterior (32.8% MVIC) and posteroanterior (31.5% MVIC). A limitation of positional grouping by force vector is that similar average excitation levels were found between vectors due to a wide variation in the different exercises. The posteroanterior force vector had the absolute highest excitation value (106.2% MVIC) for the plank with bent leg hip extension exercise while the vertical vector had the lowest excitation value (6.1% MVIC) for the squat with 0 ° trunk flexion exercise.
DISCUSSION
The purpose of this systematic review was to quantify the EMG excitation of the Gmax musculature during body weight hip extension exercises. Findings from the thirty-nine studies reviewed showed that the level of Gmax EMG excitation ranged from 6.1% to 106.2% MVIC. The wide range of Gmax EMG found from hip extension exercises in this review is comparable to the levels (4% to 103% MVIC) found in Gmax excitation during hip abduction and external rotation exercises reported by Macadam, Cronin, Contreras 23 Pooled results from in the three force vectors show a similar average level of EMG excitation between vectors: vertical (33.4%), anteroposterior (32.8%) and posteroanterior (30.5%). However, when looking at the range of EMG excitation it would seem that levels can be affected by changes in body position, which changes the direction in which force is applied to in relation to the body and the complexity of the exercise.
Vertical force vector
Twenty-five exercises were performed in the vertical vector (average: 33.4% MVIC, highest mean: single leg wall squat 86.0% MVIC). Unilateral versions of a vertical oriented exercise resulted in greater Gmax excitation than the bilateral version. This can be seen from all versions of the squat which resulted in small EMG excitation levels, compared to the single leg squat which resulted in levels of moderate, high and very high during differing versions. The single leg squat was the most used exercise (9 studies) in this vector and though its average excitation level was high (47.8% MVIC), it was found to elicit a wide range of excitation (18.9-81.2% MVIC). Reasons for range of values may relate to the depth of the squat, subject's proficiency and experience of the exercise, and the position of the free leg. This is highlighted by Ayotte, Stetts, Keenan, et al. 24 who found the highest level of EMG excitation in the single leg squat when the free leg is extended from the knee (86% MVIC). While when the free leg is flexed from the knee and behind the body, i.e. the skater squat version, the level of excitation was 66.2% MVIC.25 The single leg squat exercise was also found to result in excitation level differences between genders, with females exhibiting greater levels than males in three studies.26-28 Females were also found to exhibit greater excitation levels in single leg wall slide, lateral step down and forward step down exercises.28 Reasons for differences may relate to structural differences (females having an increased pelvic width to femoral length ratio) or differences in hip abductor strength requiring greater Gmax excitation to control the pelvis in the unilateral exercises.28 All three studies assessed exercises in the vertical vector, therefore due to the greater stability requirements in this vector it is unknown if these gender differences occur in other force vectors.
A commonly used vertical exercise was the lunge (7 studies) which resulted in a small to moderate level of excitation (11-44% MVIC), thus may be suitable as an early progressive exercise from bilateral exercises due to its split-stance two point of contact providing a base of stability that challenges balance from the wide foot base. Once mastered, progression can include forward and lateral step down exercises which elicited small excitation in males and moderate excitation in females. While subsequent progressive exercises can include the forward and lateral step up exercises which resulted in moderate to high excitation levels. Step heights can be adjusted for these exercises to further increase (or decrease) the stability requirements of the exercise. When the body is upright, greater stability requirements would be expected in hip extension movements which may be reflected in this vector having the highest average EMG excitation level. However, differences in exercises mean that a wide range of EMG levels (6.1-86.0% MVIC) were found in this vector. Exercises with a greater base of stability (squats and lunges) may be implemented for more novice subjects while greater challenges can be imposed from step up exercises to the more advanced versions of single leg squats.
Horizontal force vector (Anteroposterior)
Fourteen exercises were performed in the anteroposterior force vector (average: 32.8% MVIC, highest mean: single leg bridge 54.2% MVIC). The bridge and its unilateral version were the two most used exercises (both in 6 studies) in this vector highlighting their prominence of application. The single leg bridge was found to elicit a higher range of Gmax EMG excitation level (32.6-54.2% MVIC) than the bridge (16.4-41.5% MVIC), most likely due to the greater demands (increased load required to be stabilized with one leg off the ground) imposed by a single leg base of support compared to the bilateral position. Low levels of excitation ( < 20% MVIC) were found in bridging exercises where the feet are placed on a swiss ball or where subjects were required to perform a hamstring curl movement from a bridge position. Similarly, when performing a single leg bridge on a BOSU® surface, a lesser level of excitation (28.4% MVIC) was found compared to single leg bridge on the ground (32.6-54.2% MVIC). Therefore, it appears that when performing bridging exercises on an unstable surface (swiss ball or bosu), the level of Gmax excitation is decreased. When tactile and verbal cues to activate the glute muscle were given, EMG excitation levels increased (33.0% vs. 16.8% MVIC) compared to the regular bridge exercise, 29 thus should be a consideration for practitioners especially during exercise instruction in novice clients. Five single leg bridge exercises elicited high excitation levels with differing positions from the leg and foot on the ground, and with the leg in the air, resulting in small changes in levels of EMG %MVIC. Although altering the positions can be used to change the Gmax excitation level, when the dominant knee (i.e. the leg in contact on the ground) was flexed to 135 ° instead of 90 °, hamstring excitation decreased from 58-75% to 20-23% MVIC. 30 Therefore, for subjects who may more readily recruit the hamstrings, altering the angle of the knee reduces hamstring excitation while Gmax levels remain relatively similar. However, hamstring activity was not assessed in this review. None of the exercises in this vector elicited a very high EMG amplitude, however, exercises in this vector may be suitable as early hip extension exercises as they provide a stable base of support with the body on the ground. Progression and difficulty can be increased by having the exercises performed unilaterally while being further challenged by extending the leg in the air. Performing bridging exercises on unstable surfaces decreases Gmax excitation and thus may be more suitable for targeting other muscles or goals. Additionally, compared to many of the vertical and posteroanterior exercises, the exercises performed in this vector involve a change in body position resulting in a portion of body mass supported by the floor. This reduces the total load needing to be moved by the hip musculature.
Horizontal force vector (Posteroanterior)
Thirty-eight exercises were included in the posteroanterior vector (average: 30.5% MVIC, highest mean: plank with bent leg hip extension 106.2% MVIC). Though this vector had the highest number of exercise variations, many of the exercises are similar with small changes in either hip angles or knee angles. Many of the exercise variations in this vector replicate the testing position used to obtain %MVIC, though this vector had the lowest average EMG %MVIC level. However, of all the exercises in this review, this vector had the highest individual excitation level found in the plank with bent leg hip extension resulting in 106.2% MVIC. This suggests that when the base of support is challenged in this position (i.e. a person is only supported from one foot and their elbows), Gmax excitation is greatly increased during hip extension from this position. When performing hip extension from a quadruped position (i.e. starting with ground contact from the hands and knees), moderate to large excitation levels result. Whether the extended leg utilises knee flexion (32.2% MVIC) or extension (29.9% MVIC) resulted in similar values.19 However, when the non-dominant leg was assessed with knee flexion (21% MVIC), a difference was found compared to the dominant leg (59.7% MVIC). 25 Though subject differences could be a factor to explain the findings between the studies, Selkowitz, Beneck, Powers 19 used indwelling electrodes compared to surface electrodes which may also account for differences in results. When the arm was raised along with the leg during the quadruped exercise, the excitation level increased (56.2 % MVIC)31 most likely due to the greater stability challenge with less ground contact points for base support. Changes in excitation levels were also found from hip extension exercises performed with the hip in different positions. Performing hip extension from increased degrees of hip abduction (0 ° to 30 °) was found to increase Gmax excitation by 9% 8 and by 27% (0 ° to 15 °, also with 20 ° hip external rotation).32 Furthermore, exercise performed from different hip flexion positions (0 ° to 20 °) increased excitation by 3%,33 while hip extension from hip external rotation increased excitation by 10%.34 The position of the leg from the knee joint was also found to affect Gmax excitation levels, with Sakamoto, et al. 34 finding that knee flexion (23.1% MVIC) elicited higher excitation than knee extension (12.7% MVIC).
Two studies 35,36 using prone hip extensions exercises, found that Gmax excitation was increased (2-4%) when subjects performed abdominal drawing-in during the exercise. Similarly, when subjects braced their abdominals during prone hip extension, greater levels of excitation (4-15%) were found.20 Moreover, as found during bridging exercises, when subjects were instructed to activate their glutes during prone hip extension from 30 ° hip flexion,37 a greater level of Gmax excitation was found (21.6% vs. 9.7% MVIC) compared to the non-instructed version. Increased Gmax excitation was reported in reverse hyperextension (38.8% vs. 22.0%) and back/torso extensions (32.4% vs. 23.8%) when subjects performed a lumbopelvic control stabilsation strategy.38 These findings suggest that cueing internal mechanisms can be used to elicit greater Gmax excitation levels during different hip extension exercises. Exercise performed in this vector can be used to elicit a wide range of Gmax EMG excitation. Through altering positions of the hip (flexion, abduction, external rotation), greater excitation levels can be achieved with ground base stability. Moreover, by internal cueing mechanisms subjects can increase Gmax excitation during differing prone extensions exercises. Progression can be increased by challenging the base of support through contralateral and ipsilateral arm and leg raises during quadruped exercises, with greater challenge found during the plank base of support exercise.
Limitations
The reader should be cognizant of several limitations that affect interpretation and bias, namely that the methodological approaches varied greatly between the thirty-nine studies (see Appendix 1). Studies used different testing positions (standing, prone, supine) for determination of the MVIC, which could dramatically impact normalized levels of gluteal activation. Electrode placement (superior, inferior, mid-belly) also varied among studies. Several studies investigated the same exercise, however, differences in the way the exercises were performed need to be considered when analyzing the findings. For example, the step-up height used for step-up exercises ranged between 15.0 to 20.3 cm, therefore, differing levels of EMG activation would be an expected outcome. To most thoroughly compare EMG excitation between two studies, at the very least, their MVIC positions, electrode site placements, data processing, and amplitude presentations should be identical. Furthermore, other variables such as range of motion, relative load, effort and tempo should also be similar. This review examined muscular excitation through EMG analysis which itself has limitations when interpreting findings and providing practical suggestions. EMG is a useful tool for gaining insight into the neuromuscular system, musculoskeletal modelling, and basic science work though, its practical application is not truly clear,4 therefore, the reader needs to be cognizant of its limitations. However, despite these factors, EMG is a commonly implemented method into providing insights into how the neuromuscular system behaves and may be used as guidance to assist in understanding musculature excitation. This review summarizes information obtained from healthy subjects; therefore, vigilance is necessary when extrapolating these findings to patients with pathology. Moreover, the heterogeneity of the subjects should be considered, with differences in gender, fat mass and training status potentially affecting the findings. The risk of bias should also be noted, with three of the studies failing to adequately describe the subject's characteristics.
CONCLUSIONS
Though several limitations exist within this review, some general observations can be made as follows: 1) body weight hip extension exercises provided a wide range of Gmax EMG excitation ranging from 6.1% to 106.2% MVIC; 2) when pooled as an average, similar levels of excitation were found between force vectors though the range of excitation levels differed between vectors; 3) unilateral exercises produced higher EMG values compared to the bilateral version of the same exercise; 4) females exhibited greater EMG excitation than males in all hip extension exercises, 5) verbal and tactile cues increase Gmax EMG excitation, while bracing and drawing-in the abdominals also increase excitation levels; and, 6) hip extension exercises performed in greater degrees/angles of hip flexion, hip abduction or hip external rotation result in higher measured EMG excitation levels. The pooled averaged values for the same exercises should be interpreted as a guideline and caution should be used for interpreting their findings with further research into each exercise with the same methodology required to verify these results. Moreover, this review focused on body weight exercises, therefore, whether the loaded version of the same exercises in this review results in similar findings requires investigation. When strengthening a weaker muscle or muscle group, practitioners may wish to prescribe a gradual and progressive exercise program to ensure the targeted area is developed. Practitioners should initially consider exercises performed in the horizontal vector as they provide a large base of support and are less challenging compared to vertical vector exercises. Moreover, bi-lateral exercises should be mastered before prescribing unilateral versions. This may be of importance if individuals seek and implement a compensatory movement pattern when faced with weakness or dysfunction. Individuals may benefit from being prescribed exercises that they can perform with good technique without substitution. Subsequently, once this can be achieved, exercise difficulty can be progressed with more demanding exercises.
Appendix 1. Summary of all studies reviewed with EMG excitation (%MVIC) values given as the mean and the standard deviation. (n=39)
| Author and date | Subjects (Sex, age, height, mass) | Methodology (MVIC position and electrode site placement) | Hip extension exercises | Mean ± SD EMG excitation (%MVIC) | Quality Assessment |
|---|---|---|---|---|---|
| Worrell, Crisp, LaRosa 39 | Group 1: 6 males, 7 females (22 ± 8.6 years; 171 ± 15 cm; 69.1 ± 14.1 kg) Group 2: 13 males, 6 females (27.5 ± 5 years; 175 ± 9 cm; 73.3 ± 15.3 kg) |
Prone hip extension against manual resistance at 0 ° of hip flexion. Placement half-way between the second sacral prominence and the greater trochanter of the femur. |
Lateral step up (20 cm height) | 20 ± 11 group 1 16 ± 7 group 2 |
11 |
| Zeller, et al. 27 | 9 males (20.3 ± 1 years; 182 ± 5 cm; 78.8 ± 4.0 kg) 9 females (22 ± 8.6 years; 170 ± 6 cm; 64.3 ± 5.5 kg) |
Prone hip extension against manual resistance with knee flexed at 90 ° Placement not specified. |
Single leg squat | 62.7 ± 43 male 81.2 ± 28 female | 11 |
| Ayotte, et al. 24 | 16 males, 7 females (31.2 ± 5.8 years; 173.1 ± 10.1 cm; 77.0 ± 13.9 kg) | Supine hip extension against fixed resistance pad placed proximal to the popliteal fossa from 30 ° hip flexion. Placement 1/3rd of the distance from the second sacral vertebra to the greater trochanter. |
Forward step up (15.2 cm height) Lateral step up (15.2 cm height) Retro step up (15.2 cm height) Single leg mini squat (15.2 cm depth) Single leg wall squat, other leg knee extended |
74 ± 43 56 ± 29 59 ± 35 57 ± 43 86 ± 43 |
14 |
| Ekstrom, Donatelli, Carp 31 | 19 males, 11 females (27 ± 8 years; 176 ± 8 cm; 74 ± 11 kg) | Prone hip extension against manual resistance applied above the knee with knee flexed to 90 ° Placement between the lateral edge of the sacrum and the posterosuperior edge of the greater trochanter. |
Bridge Lateral step up (20.3 cm height) Lunge Quadruped hip extension with arm raise Single leg bridge |
25 ± 14 29 ± 13 36 ± 17 56.2 ± 22 40 ± 20 |
12 |
| Ekstrom, Osborn, Hauer 40 | 27 males, 32 females (age range 21-35 years) | Prone hip extension against manual resistance applied just above the knee with knee flexed at 90 ° Placement between the lateral edge of the sacrum and the posterosuperior edge of the greater trochanter. |
Bridge Bridge with knees extended and feet on a swiss ball |
27 ± 13 20 ± 14 |
11 |
| Farrokhi, Pollard, Souza, et al. 41 | 5 males, 5 females (26.7 ± 3.2 years) | Prone hip extension against strap resistance positioned superior to the knee joint with the knee flexed to 90 ° Placement midway between the second sacral vertebra and the greater trochanter. |
Lunge Lunge with trunk extension Lunge with trunk flexion |
18.5 ± 11.0 19.3 ± 11.8 22.3 ± 12.0 |
12 |
| Boudreau, Dwyer, Mattacola, et al. 42 | 22 males, 22 females (23.3 ± 5.1 years; 174.5 ± 9.1 cm; 74.6 ± 16.5 kg) | Standing hip extension against strap resistance placed around the distal third of the thigh with knee flexed to 90 ° Placement half the distance between the greater trochanter of the femur and the spinous process of the second sacral vertebra along an oblique angle at the level of the greater trochanter. |
Forward step-up and over (20.3 cm height) Lunge Single leg squat |
16.5 ± 11.7 21.7 ± 14.7 35.2 ± 24.0 |
14 |
| Distefano, Blackburn, Marshall, et al. 43 | 9 males, 12 females (22 ± 3 years; 171 ± 11 cm; 70.4 ± 15.3 kg) | Prone hip extension against manual resistance with knee flexed at 90 ° Placement 1/3rd of the distance between the second sacral vertebra and the greater trochanter. |
Lunge Lateral lunge Transverse lunge Single leg deadlift Single leg squat |
44 ± 23 41 ± 20 49 ± 20 59 ± 28 59 ± 27 |
12 |
| Lewis, Sahrmann 37 | 11 females (27.7 ± 6.2 years; 165.2 ± 3.6 cm; 62.3 ± 6.9 kg) | Prone hip extension against manual resistance with knee flexed at 90 ° Placement on the muscle belly. |
Prone hip extension from hip flexion of 30 ° Prone hip extension from hip flexion of 30 ° with verbal cues to activate the glutes Prone hip extension from hip flexion of 30 ° with verbal cues to activate the hamstrings |
9.7 ± 2.9 21.6 ± 9.8 11.2 ± 5.2 |
12 |
| Sakamoto, et al. 34 | 16 males, 15 females (24.5 3.5 years; 170.0 ± 9.0 cm; 66.9 ± 11.9 kg | Prone hip extension against manual resistance with knee extension Placement 1/3rd of the distance between the second sacral vertebra and the greater trochanter. |
Prone hip extension with knee extension Prone hip extension with 90 ° knee flexion Prone hip extension with lateral hip rotation and knee extension Prone hip extension with lateral hip rotation and knee flexion |
12.7 ± 8.6 23.1 ± 21.2 22.5 ± 10.4 21.2 ± 12.0 |
12 |
| Lubahn, Kernozek, Tyson, et al. 44 | 18 females (22.3 ± 2.3 years; 166.82 ± 9.2 cm; 61.1 ± 7.1 kg) | Prone hip extension against manual resistance with the knee flexed at 90 ° Placement on the muscle belly. |
Forward step up (Height unknown) Single leg squat Squat |
36.4 ± 18.6 47.4 ± 21.2 21.7 ± 15.8 |
12 |
| Boren, et al. 25 | 24 (Anthropometrical details not provided) | Prone hip extension against a strap with the knee flexed at 90 ° Placement not specified. |
Forward step up (20 cm height) Lateral step up (15 cm height) Plank with bent leg hip extension Skater squat Single leg bridge Single leg deadlift Single leg squat Quadruped bent leg hip extension DOM Quadruped bent leg hip extension non-DOM |
54.7 63.8 106.2 66.2 54.2 58.8 70.7 59.7 21.0 |
10 |
| Bouillon, Wilhelm, Eisel, et al. 45 | 20 males, 20 females (22 ± 1 years; 170 ± 10 cm; 65 ± 13 kg) | Prone hip extension against manual resistance with the knee flexed at 90 ° Placement inferior and medial to a line drawn between the PSIS and the posterior greater trochanter. |
Lateral lunge Lunge |
12 ± 3 11 ± 2.5 |
12 |
| Nakagawa, et al. 26 | 20 males (23.5 ± 3.8 years; 176 ± 6.1 cm; 74.6 ± 9.1 kg) 20 females (21.8 ± 2.6 years; 163 ± 7.3 cm; 59.4 ± 7.3 kg) |
Prone hip extension against strap with the knee flexed at 90 ° Placement parallel to the mid–muscle belly. |
Single leg squat | 24.6 ± 2.7 females 18.9 ± 8.9 males |
12 |
| Tateuchi, Taniguchi, Mori, et al. 46 | 10 males, 6 females (24.3 ± 5.2 years; 165.7 ± 7.9 cm; 59.0 ± 8.0 kg) | Prone hip extension against manual resistance. Placement halfway on the line extending between the sacrum and greater trochanter. |
Prone hip extension from 30 ° hip flexion to 10 ° hip extension | 10.9 ± 3.3 | 10 |
| De Ridder et al. 47 | 8 males, 6 females (24.7 ± 3.2 years; 172.9 ± 6.4 cm; 64.5 ± 12.5 kg) | Prone hip extension against manual resistance with the knee flexed at 90 ° Placement midway between the posterosuperior iliac spine and the ischial tuberosity. |
Prone back/torso extension Reverse hyperextension |
44.9 concentric 33.1 eccentric 30.3 concentric 20.3 eccentric |
12 |
| Kang, et al. 8 | 18 males, 12 females (22.8 ± 2.9 years; 170.3 ± 4.1 cm; 66.9 ± 10.8 kg) |
Prone hip extension against manual resistance with the knee flexed at 90 ° Placement halfway between the greater trochanter and second sacral vertebra in the middle of the muscle and at an oblique angle. |
Prone hip extension with knee flexion with hip abducted 0 ° Prone hip extension with knee flexion with hip abducted 15 ° Prone hip extension with knee flexion with hip abducted 30 ° |
20.2 ± 8.6 23.4 ± 9.9 29.6 ± 11.5 |
11 |
| Lee, Ko, Lim 48 | 20 males (22.9 ± 2.1 years; 174.4 ± 3.9 cm; 70.0 ± 6.2 kg) | Side-lying hip abduction against strap resistance with the hip in 90 ° abduction. Placement 1/3rd of the distance between the second sacral vertebra and the greater trochanter. |
Lunge Lunge with compression pelvic belt Single leg deadlift Single leg deadlift with compression pelvic belt Single leg squat Single leg squat with compression pelvic belt |
11.5 ± 6.9 13.9 ± 7.7 27.9 ± 18.4 36.3 ± 21.9 30.5 ± 19.4 35.5 ± 21.7 |
12 |
| Webster, Gribble 49 | 1 male, 8 females (22.9 ± 4.5 years; 164 ± 6.5 cm; 65.4 ± 10 kg) | Prone hip extension against manual resistance with the knee flexed at 90 ° Placement half-way between the second sacral prominence and the greater trochanter of the femur. |
Single leg squat with rotation Transverse lunge |
78 ± 45 58 ± 3 |
12 |
| Bolgla, et al. 28 | 18 males (24.3 ± 3.4 years; 180 ± 10 cm; 81.2 ± 9.7 kg) 16 females (24.0 ± 1.5 years; 165 ± 10 cm; 59.9 ± 8.8 kg) |
Prone hip extension against strap with the knee flexed at 90 ° Placement parallel alignment over the belly. |
Single leg wall slide, other leg knee flexed Single leg mini-squat Lateral step down (20 cm height) Forward step down (20 cm height) |
21.6 male 32.0 female 20.3 male 26.6 female 8.4 male 24.6 female 19.0 male 27.2 female |
12 |
| Hollman, Galardi, Lin, et al. 50 | 41 females (18-36 years) | Prone hip extension against strap with the knee flexed at 90 ° Placement at one-half the distance between the sacrum and greater trochanter. |
Single leg squat | 20.9-23.8 | 11 |
| Emami, Arab, Ghamkhar 51 | 10 males (22.5 ± 3.8 years; 177 ± 7 cm; 74.1 ± 8.0 kg) | Prone hip extension against manual resistance with the knee flexed at 90 ° Placement at the midpoint of a line running from S2 to the greater trochanter. |
Prone hip extension with knee extension | 18.3 ± 12.1 | 12 |
| MacAskill, Durant, Wallace 52 | 14 males, 20 females (21.5 ± 1.7 years; 170.5 ± 11 cm; 67.6 ± 7.5 kg) |
Prone hip extension against manual resistance with the knee flexed at 90 ° Placement 1/3rd of the distance between the second sacral vertebra and the greater trochanter. |
Forward step up (15 cm height) Lateral step up (15 cm height) |
28.7 ± 18.7 31 ± 19.9 |
11 |
| Park, Yoo 53 | 18 males (21.9 ± 2.2 years; 175.1 ± 5.3 cm; 66.6 ± 8.4 kg) |
Prone hip extension against manual resistance with the knee flexed at 90 ° Placement at half the distance between the trochanter and the sacral vertebrae in the middle of the muscle on an oblique angle. |
Back/torso extension with extended knees and hands across chest Back/torso extension with extended knees and hands behind head Back/torso extension with flexed knees 90 ° and hands across chest Back/torso extension with flexed knees 90 ° and hands behind head |
28.3 ± 14.5 26.5 ± 13.6 34.8 ± 20.6 36.6 ± 22.6 |
11 |
| Suehiro, et al. 32 | 21 males (20.2 ± 0.4 years; 171.1 ± 5.0 cm; 64.3 ± 10.5 kg) | Prone hip extension against manual resistance with the knee flexed at 90 ° Placement halfway between the greater trochanter and the second sacral vertebra. |
Prone hip extension with 90 ° knee flexion and neutral hip position Prone hip extension with 90 ° knee flexion and 15 ° hip abduction Prone hip extension with 90 ° knee flexion and 15 ° hip abduction and 20 ° hip external rotation |
14.1 ± 9.4 22.5 ± 13.6 41.0 ± 23.6 |
11 |
| Kim, Kim 54 | 14 males, 16 females (24.7 ± 3.2 years; 167.5 ± 8.2 cm; 61.5 ± 6.9 kg) | Prone hip extension against manual resistance with the knee flexed at 90 ° Placement 1/3rd the distance between the second sacral vertebrae and the greater trochanter. |
Prone hip extension to 10 ° Prone hip extension to 10 ° with abdominal drawing-in Prone hip extension to 10 ° with pelvic tilt > 15 ° Prone hip extension to 10 ° with abdominal drawing-in with pelvic tilt > 15 ° |
23.9 ± 18.5 24.4 ± 14.3 32.5 ± 21.3 45.9 ± 33.7 |
11 |
| Kim, Yoo 36 | 18 males (23.3 ± 1.8 years; 177.4 ± 5.3 cm; 74.2 ± 7.2 kg) | Prone hip extension against manual resistance with the knee flexed at 90 ° Placement not specified. |
Prone hip extension with upper body on table Prone hip extension with body on floor |
62.3 ± 27.1 56.5 ± 20.2 | 11 |
| Mills, Frank, Goto, et al. 55 | 20 females (Anthropometrical details not provided) | Prone hip extension against manual resistance with the knee flexed at 90 ° Placement 1/3rd the distance between the second sacral vertebrae and the greater trochanter |
Squat | 12.4 ± 6.3 | 11 |
| Yoon, Lee, An 33 | 15 subjects (26.7 ± 3.7 years; 167.1 ± 9.2 cm; 58.1 ± 11.7 kg) | MVIC position not specified Placement not specified |
Prone hip extension from 0 ° hip flexion Prone hip extension from 15 ° hip flexion Prone hip extension from 30 ° hip flexion |
19.7 ± 7.9 22.5 ± 9.4 18.9 ± 7.8 |
11 |
| Youdas, Hartman, Murphy, et al. 56 | 13 males (23.4 ± 1.3 years; 180 ± 10 cm; 79.7 ± 10.6 kg) 13 females (23.5 ± 1.2 years; 170 ± 10 cm; 63.7 ± 7.4 kg) |
Prone hip extension against manual resistance with the knee flexed at 90 ° Placement on the muscle belly, parallel to the line of action. |
Bridge Bridge with feet on swiss ball Single leg bridge Single leg bridge with foot on bosu Bridge with hamstring curl Bridge with feet on swiss ball and hamstring curl |
16.4 13.0 32.6 28.4 18.5 10.9 |
12 |
| Choi, Bak, Cho, et al. 57 | 14 males, 13 females (27.8 ± 5.8 years; 166.4 ± 10.1 cm; 66.2 ± 13.4 kg) | MVIC position not specified Placement between the sacrum and greater trochanter |
Bridge Single leg bridge Single leg bridge (raised leg abducted to 30 °) |
41.5 ± 16.4 47.3 ± 16.0 46.7 ± 12.0 |
11 |
| Jeon, et al. 35 | 16 males (25.4 ± 4.2 years; 174.7 ± 2.8 cm; 73.1 ± 2.1 kg) | Prone hip extension against manual resistance with the knee flexed at 90 ° Placement at the midpoint of the line extending between the greater trochanter and sacrum |
Prone hip extension with upper body on table Prone hip extension with upper body on table and abdominals drawing-in Prone hip extension with upper body on table and flexed contralateral knee joint on a chair |
43.9 ± 16.1 47.5 ± 19.8 66.4 ± 25.8 |
12 |
| Lee, Song, Kwon 58 | 10 males, 10 females (21.1 ± 1.8 years; 168.7 ± 8.3 cm; 66.1 ± 12.3 kg) | MVIC method not specified. Placement at 50% on the line between the sacral vertebrae and the greater trochanter |
Squat with 0 ° trunk flexion Squat with 15 ° trunk flexion Squat with 30 ° trunk flexion |
6.1 ± 4.0 6.3 ± 4.0 8.0 ± 4.9 |
11 |
| Selkowitz, Beneck, Powers 19 | 10 males, 10 females (27.9 ± 6.2 years; 170.5 ± 11.1 cm; 67.7 ± 14.1 kg) | Four conditions normalised to whichever contraction elicited greater EMG excitation: 1) Prone hip extension of 45 ° with the knee flexed at 90 ° against strap resistance. 2) Prone hip extension of 0 ° with the knee flexed at 90 ° against strap resistance. 3) Sidelying position with hip in 30 ° abduction and knee extended against strap. 4) As position 3 with hip in 45 ° flexion. Placement Gmax (S) inserted superior and lateral to the midpoint of a line drawn between the posterior superior iliac spine and the posterior greater trochanter, Gmax (I) inserted inferior and medial to the midpoint of the same line, such that it was 2.5 to 5.0 cm above the gluteal fold. |
Bridge Forward step up Lunge Single leg bridge Squat Quadruped hip extension with knee extended Quadruped hip extension with knee flexed |
17.4 ± 12.0 (S) 22.3 ± 10.1 (I) 22.8 ± 15.6 (S) 15.7 ± 6.0 (I) 20.1 ± 11.1 (S) 18.5 ± 6.2 (I) 34.6 ± 16.8 (S) 36.7 ± 10.0 (I) 12.9 ± 7.9 (S) 10.5 ± 7.1 (I) 28.5 ± 16.6 (S) 31.2 ± 16.5(I) 30.1 ± 12.5 (S) 34.3 ± 16.3 (I) |
12 |
| Chan, et al. 20 | 10 males, 10 females (21.1 ± 1.7 years; 166.8 ± 7.9 cm; 58.1 ± 9.2 kg) | Prone hip extension against manual resistance with the knee flexed at 90 ° Placement 1/3rd of the distance from iliac crest to greater trochanter, starting from greater trochanter. |
Prone hip extension up to 20 ° with 90 ° knee flexion Prone hip extension up to 20 ° with 90 ° knee flexion with abdominal bracing |
14.8 concentric (S) 12.3 eccentric (S) 20.1 concentric (I) 11.7 eccentric (I) 19.7 concentric (S) 16.6 eccentric (S) 25.6 concentric (I) 36.0 eccentric (I) |
12 |
| Hollman, et al. 29 | 15 females (23.3 ± 1.7 years; 169.4 ± 8.3 cm; 62.6 ± 6.7 kg) | Prone hip extension against strap resistance with the knee flexed at 90 ° Placement halfway between the sacral vertebrae and the greater trochanter |
Bridge Bridge with verbal and tactile cueing |
16.8 33.0 |
13 |
| Lehecka, et al. 30 | 12 males, 16 females (23.4 ± 2.3 years; 173 ± 11 cm; 72.6 ± 13.9 kg) | Prone hip extension against strap resistance with the knee flexed at 90 ° Placement anterosuperior to Gmax, inferior to the lateral aspect of the iliac crest on a line towards the greater trochanter on the muscle belly. |
Single leg bridge. DOM leg 90 ° knee flexion with foot flat. Non-DOM leg knee extended Single leg bridge. DOM leg 135 ° knee flexion with foot flat. Non-DOM leg knee extended Single leg bridge. DOM leg 90 ° knee flexion with foot flat. Non-DOM leg knee relaxed in flexion and femur vertical Single leg bridge. DOM leg 90 ° knee flexion with dorsiflexed ankle. Non-DOM leg knee relaxed in flexion and femur vertical Single leg bridge. DOM leg 135 ° knee flexion with dorsiflexed ankle. Non-DOM leg knee relaxed in flexion and femur vertical |
51.0 ± 28.1 47.4 ± 24.8 47.2 ± 28.1 49.1 ± 26.4 40.4 ± 24.6 |
11 |
| Van Oosterwijck, et al. 38 | 4 males, 9 females (22.6 ± 2.1 years; 172 ± 7.3 cm; 61.3 ± 9.5 kg) | Prone hip extension against manual resistance with the knee flexed at 90 ° Placement midway between the posterosuperior iliac spine and the ischial tuberosity). |
Prone back/torso extension without lumbopelvic control strategy Prone back/torso extension with lumbopelvic control strategy Reverse hyperextension without lumbopelvic control strategy Reverse hyperextension with lumbopelvic control strategy |
23.8 ± 10.1 32.4 ± 21.6 22.0 ± 7.7 38.8 ± 24.1 |
12 |
| Youdas, et al. 2 | 13 males, 13 females (23.5 ± 1.2 years; 175.0 ± 10.0 cm; 71.7 ± 9.0 kg) | Prone hip extension against manual resistance with the knee flexed at 90 ° Placement parallel to the muscle's line of action. |
Single leg bridge Supine manual resisted hip extension |
33.8 34.7 |
12 |
BM = body mass, DOM = dominant, EMG = electromyography, Gmax = Gluteus Maximus, I = inferior, MVIC = maximum voluntary isometric contraction, ROM = range of motion, S = superior
References
- 1.Neumann DA. Kinesiology of the hip: a focus on muscular actions. J Orthop Sports Phys Ther. 2010;40(2):82-94. [DOI] [PubMed] [Google Scholar]
- 2.Youdas JW Hartman JP Murphy BA, et al. Electromyographic analysis of gluteus maximus and hamstring activity during the supine resisted hip extension exercise versus supine unilateral bridge to neutral. Physio Theory Pract. 2017;33(2):124-130. [DOI] [PubMed] [Google Scholar]
- 3.Cochrane DJ Harnett MC Pinfold SC. Does short-term gluteal activation enhance muscle performance? Res Sports Med. 2017;25(2):156-165. [DOI] [PubMed] [Google Scholar]
- 4.Vigotsky AD Halperin I Lehman GJ, et al. Interpreting Signal Amplitudes in Surface Electromyography Studies in Sport and Rehabilitation Sciences. Front Physiol. 2017;8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.De Luca CJ. The use of surface electromyography in biomechanics. J Appl Biomech. 1997;13(2):135-163. [Google Scholar]
- 6.Andersen LL Magnusson SP Nielsen M, et al. Neuromuscular activation in conventional therapeutic exercises and heavy resistance exercises: implications for rehabilitation. Physi Ther. 2006;86(5):683-697. [PubMed] [Google Scholar]
- 7.Wakahara T Fukutani A Kawakami Y, et al. Nonuniform muscle hypertrophy: its relation to muscle activation in training session. Med Scie Sports Exerc. 2013;45(11):2158-2165. [DOI] [PubMed] [Google Scholar]
- 8.Kang S-Y Jeon H-S Kwon O, et al. Activation of the gluteus maximus and hamstring muscles during prone hip extension with knee flexion in three hip abduction positions. Man Ther. 2013;18(4):303-307. [DOI] [PubMed] [Google Scholar]
- 9.Kisner C Colby LA. Therapeutic Exercise: Foundations and Techniques. 6th ed Philadelphia, PA: Fa Davis; 2012. [Google Scholar]
- 10.Contreras B. Force Vector Training. NSCA Strongest Links Retrieved: https://www.nsca.com/Education/Articles/Force-Vector-Training/.
- 11.Reid C Dolan M DeBeliso M. The Reliability of the Standing Long Jump in NCAA Track and Field Athletes. Int J Sports Sci. 2017;7(6):233-238. [Google Scholar]
- 12.Gonzalo-Skok O Tous-Fajardo J Valero-Campo C, et al. Eccentric Overload Training in Team-Sports Functional Performance: Constant Bilateral Vertical vs. Variable Unilateral Multidirectional Movements. Int J Sports Physiol Perf. 2016:1-23. [DOI] [PubMed] [Google Scholar]
- 13.Young WB. Transfer of strength and power training to sports performance. Int J Sports Physiol Perform. 2006;1(2):74. [DOI] [PubMed] [Google Scholar]
- 14.Contreras B Vigotsky AD Schoenfeld BJ, et al. A comparison of gluteus maximus, biceps femoris, and vastus lateralis electromyographic activity in the back squat and barbell hip thrust exercises. J Appl Biomech. 2015;31(6):452-458. [DOI] [PubMed] [Google Scholar]
- 15.Andersen V Fimland MS Mo D-A, et al. Electromyographic Comparison Of Barbell Deadlift, Hex Bar Deadlift And Hip Thrust Exercises: A Cross-Over Study. J Strength Condi Res. 2017; 32(3):587-593. [DOI] [PubMed] [Google Scholar]
- 16.Moher D Liberati A Tetzlaff J, et al. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. Annals Intl Med. 2009;151(4):264-269. [DOI] [PubMed] [Google Scholar]
- 17.Downs SH Black N. The feasibility of creating a checklist for the assessment of the methodological quality both of randomised and non-randomised studies of health care interventions. J Epid Comm Health. 1998;52(6):377-384. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Moens M Goudman L Brouns R, et al. Return to Work of Patients Treated With Spinal Cord Stimulation for Chronic Pain: A Systematic Review and Meta-Analysis. Neuromod: Techn Neur Interf. 2018. [DOI] [PubMed] [Google Scholar]
- 19.Selkowitz DM Beneck GJ Powers CM. Comparison of Electromyographic Activity of the Superior and Inferior Portions of the Gluteus Maximus Muscle During Common Therapeutic Exercises. J Orthop Sports Phys Ther. 2016;46(9):794-799. [DOI] [PubMed] [Google Scholar]
- 20.Chan MK Chow KW Lai AY, et al. The effects of therapeutic hip exercise with abdominal core activation on recruitment of the hip muscles. BMC Muscul Dis. 2017;18(1):313. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Escamilla RF Lewis C Bell D, et al. Core muscle activation during Swiss ball and traditional abdominal exercises. J Orthop Sports Phys Ther. 2010;40(5):265-276. [DOI] [PubMed] [Google Scholar]
- 22.Youdas JW Adams KE Bertucci JE, et al. Muscle activation levels of the gluteus maximus and medius during standing hip-joint-strengthening exercises using elastic-tubing resistance. J Sport Rehab. 2014;23(1):1-11. [DOI] [PubMed] [Google Scholar]
- 23.Macadam P Cronin J Contreras B. An examination of the gluteal muscle activity associated with dynamic hip abduction and hip external rotation exercise: A systematic review. Int J Sports Phys Ther 2015;10(5):573. [PMC free article] [PubMed] [Google Scholar]
- 24.Ayotte NW Stetts DM Keenan G, et al. Electromyographical analysis of selected lower extremity muscles during 5 unilateral weight-bearing exercises. J Orthop Sports Phy Ther. 2007;37(2):48-55. [DOI] [PubMed] [Google Scholar]
- 25.Boren K Conrey C Le Coguic J, et al. Electromyographic analysis of gluteus medius and gluteus maximus during rehabilitation exercises. Int J Sports Phys Ther. 2011;6(3):206. [PMC free article] [PubMed] [Google Scholar]
- 26.Nakagawa TH Moriya ET Maciel CD, et al. Trunk, pelvis, hip, and knee kinematics, hip strength, and gluteal muscle activation during a single-leg squat in males and females with and without patellofemoral pain syndrome. J Orthop Sports Phy Ther. 2012;42(6):491-501. [DOI] [PubMed] [Google Scholar]
- 27.Zeller BL McCrory JL Ben Kibler W, et al. Differences in kinematics and electromyographic activity between men and women during the single-legged squat. Amer J Sports Med. 2003;31(3):449-456. [DOI] [PubMed] [Google Scholar]
- 28.Bolgla L Cook N Hogarth K, et al. Trunk and hip electromyographic activity during single leg squat exercises do sex differences exist? Int J Sports Phys Ther. 2014;9(6):756. [PMC free article] [PubMed] [Google Scholar]
- 29.Hollman JH Berling TA Crum EO, et al. Do Verbal and Tactile Cueing Selectively Alter Gluteus Maximus and Hamstring Recruitment During a Supine Bridging Exercise in Active Females? A Randomized Controlled Trial. J Sport Rehab. 2017:1-22. [DOI] [PubMed] [Google Scholar]
- 30.Lehecka B Edwards M Haverkamp R, et al. Building a better gluteal bridge: Electromyographic analysis of hip muscle activity during modified single-leg bridges. Int J Sports Phys Ther. 2017;12(4):543. [PMC free article] [PubMed] [Google Scholar]
- 31.Ekstrom RA Donatelli RA Carp KC. Electromyographic analysis of core trunk, hip, and thigh muscles during 9 rehabilitation exercises. J Orthop Sports Phys Ther. 2007;37(12):754-762. [DOI] [PubMed] [Google Scholar]
- 32.Suehiro T Mizutani M Okamoto M, et al. Influence of hip joint position on muscle activity during prone hip extension with knee flexion. J Phys Ther Sci. 2014;26(12):1895-1898. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 33.Yoon J-Y Lee M-R An D-H. Effect of initial position on the muscle activity of the hip extensors and amount of pelvic tilt during prone hip extension. J Phys Ther Sci.. 2015;27(4):1195-1197. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 34.Sakamoto A Teixeira-Salmela L Rodrigues dPF, et al. Gluteus maximus and semitendinosus activation during active prone hip extension exercises. Brazilian J Phys Ther. 2009;13(4):335-342. [Google Scholar]
- 35.Jeon I-c Kwon O-y Weon J-h, et al. Comparison of Hip and Back Muscle Activity and Pelvic Compensation in Healthy Subjects During Three Different Prone Table Hip Extension Exercises. J Sport Rehab. 2016:1-19. [DOI] [PubMed] [Google Scholar]
- 36.Kim S-m Yoo W-g. Comparison of trunk and hip muscle activity during different degrees of lumbar and hip extension. J Phys Ther Sci. 2015;27(9):2717-2718. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 37.Lewis CL Sahrmann SA. Muscle activation and movement patterns during prone hip extension exercise in women. J Athle Train. 2009;44(3):238-248. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 38.Van Oosterwijck J De Ridder E Vleeming A, et al. Applying an active lumbopelvic control strategy during lumbar extension exercises: Effect on muscle recruitment patterns of the lumbopelvic region. Human Move Sci. 2017;54:24-33. [DOI] [PubMed] [Google Scholar]
- 39.Worrell TW Crisp E LaRosa C. Electromyographic reliability and analysis of selected lower extremity muscles during lateral step-up conditions. J Athl Train. 1998;33(2):156. [PMC free article] [PubMed] [Google Scholar]
- 40.Ekstrom RA Osborn RW Hauer PL. Surface electromyographic analysis of the low back muscles during rehabilitation exercises. J Orthop Sports Phys Ther. 2008;38(12):736-745. [DOI] [PubMed] [Google Scholar]
- 41.Farrokhi S Pollard CD Souza RB, et al. Trunk position influences the kinematics, kinetics, and muscle activity of the lead lower extremity during the forward lunge exercise. J J Orthop Sports Phys Ther. 2008;38(7):403-409. [DOI] [PubMed] [Google Scholar]
- 42.Boudreau SN Dwyer MK Mattacola CG, et al. Hip-muscle activation during the lunge, single-leg squat, and step-up-and-over exercises. J Sport Rehab. 2009;18(1):91-103. [DOI] [PubMed] [Google Scholar]
- 43.Distefano LJ Blackburn JT Marshall SW, et al. Gluteal muscle activation during common therapeutic exercises. J Orthop Sports Phys Ther. 2009;39(7):532-540. [DOI] [PubMed] [Google Scholar]
- 44.Lubahn AJ Kernozek TW Tyson TL, et al. Hip muscle activation and knee frontal plane motion during weight bearing therapeutic exercises. Int J Sports Phys Ther. 2011;6(2):92. [PMC free article] [PubMed] [Google Scholar]
- 45.Bouillon LE Wilhelm J Eisel P, et al. Electromyographic assessment of muscle activity between genders during unilateral weight-bearing tasks using adjusted distances. Int J Sports Phys Ther. 2012;7(6):595. [PMC free article] [PubMed] [Google Scholar]
- 46.Tateuchi H Taniguchi M Mori N, et al. Balance of hip and trunk muscle activity is associated with increased anterior pelvic tilt during prone hip extension. J Electrom Kin. 2012;22(3):391-397. [DOI] [PubMed] [Google Scholar]
- 47.De Ridder EM Van Oosterwijck JO Vleeming A, et al. Posterior muscle chain activity during various extension exercises: an observational study. BMC Muscul Dis. 2013;14(1):204. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 48.Lee KS Ko E Lim CG. Effect of pelvic belt on gluteal muscles activity during therapeutic exercise. J Physl Ther Sci. 2013;25(3):337-340. [Google Scholar]
- 49.Webster K Gribble P. A comparison of electromyography of gluteus medius and maximus in subjects with and without chronic ankle instability during two functional exercises. Phys Ther in Sport. 2013;14(1):17-22. [DOI] [PubMed] [Google Scholar]
- 50.Hollman JH Galardi CM Lin I-H, et al. Frontal and transverse plane hip kinematics and gluteus maximus recruitment correlate with frontal plane knee kinematics during single-leg squat tests in women. Clin Biomech. 2014;29(4):468-474. [DOI] [PubMed] [Google Scholar]
- 51.Emami M Arab AM Ghamkhar L. The activity pattern of the lumbo-pelvic muscles during prone hip extension in athltes with and without hamstring strain injuy. Int J Sports Phys Ther. 2014;9(3):312. [PMC free article] [PubMed] [Google Scholar]
- 52.MacAskill MJ Durant TJ Wallace DA. Gluteal muscle actvity during weightbearing and non-weightbearing exercise. Int J Sports Phys Ther. 2014;9(7):907. [PMC free article] [PubMed] [Google Scholar]
- 53.Park S-y Yoo W-g. Effects of hand and knee positions on muscular activity during trunk extension exercise with the Roman chair. J Electrom Kin. 2014;24(6):972-976. [DOI] [PubMed] [Google Scholar]
- 54.Kim TW Kim YW. Effects of abdominal drawing-in during prone hip extension on the muscle activities of the hamstring, gluteus maximus, and lumbar erector spinae in subjects with lumbar hyperlordosis. J Phys Ther Scie. 2015;27(2):383-386. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 55.Mills M Frank B Goto S, et al. Effect of restricted hip flexor muscle length on hip extensor muscle activity and lower extremity biomechanics in college-aged female soccer players. Int J Sports Phys Ther. 2015;10(7):946. [PMC free article] [PubMed] [Google Scholar]
- 56.Youdas JW Hartman JP Murphy BA, et al. Magnitudes of muscle activation of spine stabilizers, gluteals, and hamstrings during supine bridge to neutral position. Physio Theory Pract. 2015;31(6):418-427. [DOI] [PubMed] [Google Scholar]
- 57.Choi K Bak J Cho M, et al. The effects of performing a one-legged bridge with hip abduction and use of a sling on trunk and lower extremity muscle activation in healthy adults. J Phys The Sci. 2016;28(9):2625-2628. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 58.Lee T-S Song M-Y Kwon Y-J. Activation of back and lower limb muscles during squat exercises with different trunk flexion. J Phys The Sci. 2016;28(12):3407-3410. [DOI] [PMC free article] [PubMed] [Google Scholar]