Intramuscular Neural Distribution of the Gluteus Maximus Muscle: Diagnostic Electromyography and Injective Treatments

INTRODUCTION

The purpose of this study was to investigate neural patterns within the gluteus maximus (Gmax) muscle to identify optimal EMG placement and injection sites for botulinum toxin and other injectable agents.

METHODS

This study used 10 fixed and 1 non-fixed adult Korean cadavers. Intramuscular arborization patterns were confirmed in the cranial, middle, and caudal segments of 20 Gmax muscles using Sihler staining. Ultrasound images were obtained from one cadaver, and blue dye was injected using ultrasound guidance to confirm the results.

RESULTS

The intramuscular innervation pattern of the Gmax was mostly in the middle part of this muscle. The nerve endings of the Gmax are mainly located in the 40-70% range in the cranial segment, the 30-60% range in the middle segment, and the 40-70% range in the caudal segment.

DISCUSSION

Addressing the spasticity of the gluteus maximus requires precise, site-specific botulinum toxin injections. The use of EMG and other injection therapies should be guided by the findings of this study. We propose that these specific sites, which correspond to areas with the densest nerve branches, are the safest and most efficient locations for both botulinum toxin injections and EMG procedures.

Electromyographic differences of the gluteus maximus, gluteus medius, biceps femoris, and vastus lateralis between the barbell hip thrust and barbell glute bridge

Hip extensor muscles are critical to sport performance as events requiring sprinting and forceful landings are highly dependent on these muscles. Despite biomechanical differences between the barbell hip thrust (BHT) and the barbell glute bridge (BGB), both are biomechanically efficient ways to load this musculature for training purposes. Research investigating the differences in muscular activity between the BHT and BGB has yet been conducted. The aim of this study was to investigate, through surface electromyography, if one exercise is more optimal than the other in producing greater muscle activation for specific hip extensor muscles. Ten male participants completed a two-part study protocol. Results revealed the BHT elicited significantly greater muscle activity within the vastus lateralis for peak and mean outcomes; however, the BGB elicited significantly greater muscle activity in the upper and lower gluteus maximus for peak and mean outcomes and mean outcome in the gluteus medius. Current findings suggest, the BGB is, at minimum, a superior substitute for the BHT for eliciting a larger magnitude of activity in the gluteus maximus. Future studies between the two exercises are warranted to discern which produces greater hypertrophy and whether adaption of the BHT or BGB transfers more optimally to sport performance.

Comparison of Regional Hamstrings Activation During Resistance Exercises in Females With Prior Athletic Experience

CONTEXT

Within each hamstring muscle, there are segments with separate nerve innervation. However, a better understanding of activation levels within these regions during resistance exercise could lead to region-specific training for improved performance and injury prevention.

OBJECTIVE

To compare muscle activation levels within regions of the hamstrings during various resistance exercises.

DESIGN

Within-subjects repeated measures.

SETTING

Biomechanics laboratory.

PARTICIPANTS

Eighteen young adult females with previous competitive sport participation and resistance training experience.

INTERVENTION

One set of 3 repetitions with an 8RM load on the bilateral squat, modified single-leg squat, stiff-legged dead lift, and leg curl (LC).

MAIN OUTCOME MEASURES

Normalized surface electromyography of 4 hamstring regions (proximal-medial, proximal-lateral, distal-medial, and distal-lateral).

RESULTS

For LC only, electromyography measures for the proximal-lateral location were significantly lower than for the distal-lateral, t18 = 5.6, P < .001, and proximal-medial, t18 = 2.4, P = .01 locations for concentric contractions. Similar results were observed for eccentric contractions. No other exercises revealed regional activation differences. When comparing the pooled proximal (medial and lateral) region across exercises, the LC demonstrated significantly greater activation than the modified single-leg squat, t18 = 5.20, P < .001, stiff-legged dead lift, t18 = 7.311, P < .001, and bilateral squat, F3,54 = 49.8, P < .001. Similar significantly greater levels were also found during the LC for the pooled distal, medial, and lateral regions. In addition, the modified single-leg squat electromyography was significantly greater at all regions in comparison with the stiff-legged dead lift and bilateral squat.

CONCLUSIONS

The data did not reveal consistent regional differences within the different exercises included in this study. However, the data indicate that the LC produces the highest hamstring activation in all regions across exercises. Inclusion of single-joint knee-flexion exercises would appear to be most beneficial for hamstrings development in a resistance-training program.

Determining the most effective exercise for gluteal muscle activation in children with cerebral palsy using surface electromyography

BACKGROUND

Reduced lumbo-pelvic postural control is a common feature of gait in children with Cerebral Palsy (CP). These features are commonly attributed to insufficiency of the hip musculature as well as underlying bony geometry. Exercises aimed at strengthening the hip muscles are frequently prescribed in children with Cerebral Palsy (CP). There is a lack of evidence indicating the most effective exercises in targeting gluteal muscle activation in this population.

RESEARCH QUESTION

To determine the most effective exercise for gluteal muscle activation in children with CP.

METHODS

This was a cross-sectional study of children with CP. Surface EMG data from the gluteus medius (GMed) and maximus (GMax) on the more involved limb were recorded as participants completed 6 commonly prescribed gluteal strengthening exercises. EMG was assessed for peak activation, normalised to functional reference values.

RESULTS

Data from ten children (5 males, 5 females; mean +- SD age, 13+-3 years) were included for final analysis. The single leg bridge and step up were the most effective exercises for gluteal muscle activation. Differences in activation were found to be statistically significant using Friedman's rank test (GMax p = 0.0001, GMed p = 0.0023).

SIGNIFICANCE

This study is the first to show clear differences in activation across gluteal strengthening exercises in a CP population. Exercises which involve weight bearing through a single limb appear most effective in activating the target muscles i.e the single leg bridge and the step up. Exercises involving double limb support or open-chain movements were less effective. The results of this study indicate that careful exercise selection is required to achieve targeted muscle activation in a paediatric CP population. The results of this study will provide guidance for exercise prescription for gluteal strengthening in this population and will inform future research studies on the effectiveness hip muscle strengthening programmes in CP.

Does short-term gluteal activation enhance muscle performance?

A reduction in gluteus maximus (GM) strength may contribute to the etiology of musculoskeletal impairments and lower-extremity injuries. Currently, there is a paucity of evidence regarding the efficacy of implementing a short-term gluteal activation programme to improving muscle performance. Twenty four semi-professional rugby males were assigned randomly to a gluteal activation group (GLUTE) or a control group (CON). During the 6-week training intervention, the GLUTE and CON groups performed the same training, however that GLUTE group performed seven gluteal activation exercises three times weekly prior to their normal training sessions. Whilst the CON group performed the conventional training with no gluteal activation exercises. Electromyography (EMG) was measured during a maximal isometric unilateral squat (MVIC) and unilateral hip extension force from the left and right vastus lateralis, gluteus maximus, and biceps femoris. After 6 weeks of training there was no significant main or interaction effect (p > 0.05) of EMG and peak force for MVIC and hip extension between GLUTE and CON. The current gluteal activation programme did not enhance EMG activity and hip extension force therefore, the body-weight exercises may not have been sufficient to elicit the appropriate changes.

The effect of exercise hypertrophy and disuse atrophy on muscle contractile properties: a mechanomyographic analysis

PURPOSE

To determine whether mechanomyographic (MMG) determined contractile properties of the biceps brachii change during exercise-induced hypertrophy and subsequent disuse atrophy.

METHODS

Healthy subjects (mean ± SD, 23.7 ± 2.6 years, BMI 21.8 ± 2.4, n = 19) performed unilateral biceps curls (9 sets × 12 repetitions, 5 sessions per week) for 8 weeks (hypertrophic phase) before ceasing exercise (atrophic phase) for the following 8 weeks (non-dominant limb; treatment, dominant limb; control). MMG measures of muscle contractile properties (contraction time; T _c, maximum displacement; D _max, contraction velocity; V _c), electromyographic (EMG) measures of muscle fatigue (median power frequency; MPF), strength measures (maximum voluntary contraction; MVC) and measures of muscle thickness (ultrasound) were obtained.

RESULTS

Two-way repeated measures ANOVA showed significant differences (P < 0.05) between treatment and control limbs. During the hypertrophic phase treatment MVC initially declined (weeks 1-3), due to fatigue (decline in MPF), followed by improvement against control during weeks 6-8. Between weeks 5 and 8 treatment, muscle thickness was greater than control, reflecting gross hypertrophy. MMG variables Dmax (weeks 2, 7) and Vc (weeks 7, 8) declined. During the atrophic phase, MVC (weeks 9-12) and muscle thickness (weeks 9, 10) initially remained high before declining to control levels, reflecting gross atrophy. MMG variables D _max (weeks 9, 14) and V _c (weeks 9, 14, 15) also declined during the atrophic phase. No change in T _c was found throughout the hypertrophic or atrophic phases.

CONCLUSIONS

MMG detects changes in contractile properties during stages of exercise-induced hypertrophy and disuse atrophy suggesting its applicability as a clinical tool in musculoskeletal rehabilitation.

A comparison of two gluteus maximus EMG maximum voluntary isometric contraction positions

Background. The purpose of this study was to compare the peak electromyography (EMG) of the most commonly-used position in the literature, the prone bent-leg (90°) hip extension against manual resistance applied to the distal thigh (PRONE), to a novel position, the standing glute squeeze (SQUEEZE).

Methods. Surface EMG electrodes were placed on the upper and lower gluteus maximus of thirteen recreationally active females (age = 28.9 years; height = 164 cm; body mass = 58.2 kg), before three maximum voluntary isometric contraction (MVIC) trials for each position were obtained in a randomized, counterbalanced fashion.

Results. No statistically significant (p < 0.05) differences were observed between PRONE (upper: 91.94%; lower: 94.52%) and SQUEEZE (upper: 92.04%; lower: 85.12%) for both the upper and lower gluteus maximus. Neither the PRONE nor SQUEEZE was more effective between all subjects.

Conclusions. In agreement with other studies, no single testing position is ideal for every participant. Therefore, it is recommended that investigators employ multiple MVIC positions, when possible, to ensure accuracy. Future research should investigate a variety of gluteus maximus MVIC positions in heterogeneous samples.

Isometric hip abduction using a Thera-Band alters gluteus maximus muscle activity and the anterior pelvic tilt angle during bridging exercise

The purpose of this study was to investigate the effects of bridging with isometric hip abduction (IHA) using the Thera-Band on gluteus maximus (GM), hamstring (HAM), and erector spinae (ES) muscle activity; GM/HAM and GM/ES ratios; and the anterior pelvic tilt angle in healthy subjects. Twenty-one subjects participated in this study. Surface EMG was used to collect EMG data of GM, HAM, and ES muscle activities, and Image J software was used to measure anterior pelvic tilt angle. A paired t-test was used to compare GM, HAM, and ES muscle activity; the GM/HAM and GM/ES ratios; and the anterior pelvic tilt angle with and without IHA during the bridging exercise. GM muscle activity increased significantly and the anterior pelvic tilt angle decreased significantly during bridging with IHA using the Thera-Band (p < 0.05). However, there were no significant differences in the activity of the HAM and ES and the GM/HAM and GM/ES ratios between bridging with and without IHA (p > 0.05). The results of this study suggest that bridging with IHA using the Thera-Band can be implemented as an effective method to facilitate GM muscle activity and reduce the anterior pelvic tilt angle.

Design and evaluation of a novel microphone-based mechanomyography sensor with cylindrical and conical acoustic chambers

Mechanomyography has recently been proposed as a control modality for alternative access technologies for individuals with disabilities. However, MMG recordings are highly susceptible to contamination from limb movements. Pressure-based transducers are touted to be the most robust to external movement although there is some debate about their optimal chamber geometry, in terms of low frequency gain and spectral flatness. To investigate the question of preferred geometry, transducers with cylindrical and conical chambers of varying dimensions were designed, manufactured and tested. Using a computer-controlled electrodynamic shaker, the frequency response of each chamber geometry was empirically derived. Of the cylindrical chambers, the highest gain and the flattest frequency response was exhibited by a chamber 10 mm in diameter and 5-7 mm in height. However, conical chambers offered an average rise in gain of 6.79 ± 1.06 dB/Hz over that achievable with cylindrical geometries. The highest gain and flattest response was achieved with a transducer consisting of a low-frequency MEMS microphone, a 4 μm aluminized mylar membrane and a rigid conical chamber 7 mm in diameter and 5mm in height. This design is recommended for MMG applications where limb movement is prevalent.