Influence of Hip Joint Position on Muscle Activity during Prone Hip Extension with Knee Flexion

Weight-Bearing Versus Traditional Strength Assessments of the Hip Musculature

CONTEXT

Traditional nonweight-bearing (NWB) hip-strength assessments may not directly translate to functional strength during weight-bearing (WB) activity. How NWB assessments of hip muscle strength compare with WB assessments in various positions is currently unknown.

OBJECTIVE

To determine the magnitude of the differences and correlations between NWB hip strength and WB functional strength during the squatting and lunge (LNG) positions in female athletes.

DESIGN

Crossover design.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Female athletes (N = 51, age = 16.2 ± 3.5 years, height = 161.5 ± 8.3 cm, mass = 58.3 ± 11.6 kg).

INTERVENTION(S)

Isometric resistance (N/kg) was determined for the dominant and nondominant limbs via WB assessments (squat-bilateral [legs tested simultaneously], squat-unilateral, and lunge positions) and NWB assessments (hip abduction [HAB], hip extension HEXT], and hip external rotation [HER]).

MAIN OUTCOME MEASURE(S)

To compare differences between positions (P ≤ .05), we used effect sizes (d) and matched-pairs t tests, and we calculated Pearson r and R2 values.

RESULTS

During the squat-bilateral on the dominant limb, females produced the most hip torque (6.13 ± 1.12 N/kg). The magnitudes of differences were very large compared with HER (3.96 ± 0.83, d = 2.2), HEXT (3.22 ± 0.69, d = 3.2), and HAB (3.80 ± 1.01, d = 2.2; all P values ≤ .01), and positions were moderately correlated (r = 0.347-0.419, R2 = 0.12-0.18). The lunge position produced the least amount of torque in the dominant limb (2.44 ± 0.48 N/kg) compared with HER (d = -2.3), HEXT (d = -1.3), and HAB (d = -1.7; all P values ≤ .001), and correlations were small to moderate (r = 0.236-0.310, R2 = 0.06-0.10).

CONCLUSIONS

Strength in WB positions was different than strength evaluated using traditional NWB assessments in female athletes. Weight-bearing tests may provide clinicians with additional information regarding strength and function.

EXAMINATION OF GLUTEUS MAXIMUS ELECTROMYOGRAPHIC EXCITATION ASSOCIATED WITH DYNAMIC HIP EXTENSION DURING BODY WEIGHT EXERCISE: A SYSTEMATIC REVIEW

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.

Comparison of hip extensor muscle activity including the adductor magnus during three prone hip extension exercises

OBJECTIVES

This study compared the role of the adductor magnus muscle (Amag) as a hip extensor while performing active prone hip extension (PHE), PHE with hip adduction (PHE-ADD), and PHE with hip abduction (PHE-ABD) with the gluteus maximus (Gmax) and hamstrings.

METHODS

The study recruited 22 healthy participants. Electromyography data were recorded from the Amag, Gmax, and medial and lateral hamstrings during PHE, PHE-ADD, and PHE-ABD. Normalized electromyographic data were examined using one-way, repeated-measures analyses of variance.

RESULTS

The magnitude of the Amag, Gmax, and hamstring activations did not differ significantly while performing PHE (p = 0.41). Furthermore, the Amag and hamstring activations were significantly greater than the Gmax activation when performing PHE-ADD (p < 0.05). The Gmax showed significantly greater activation during PHE-ABD than the Amag and medial and lateral hamstrings (p < 0.05).

CONCLUSIONS

Based on these results, we advocate including the Amag as a hip extensor during the PHE test or exercise. Our preliminary results have the potential to be applied directly to the PHE test, for investigating the muscle-activation pattern of the Amag with the Gmax and hamstrings in patients with hip or lower back pain.

Piriformis electromyography activity during prone and side-lying hip joint movement

[Purpose] To measure electromyographic activity of the piriformis using fine-wire electrodes during 7 hip movements. [Subjects and Methods] Eleven healthy men, without severe low back pain or lower limb injury, participated in this study. Fine-wire electrodes were inserted into the piriformis and surface electrodes were attached to the muscles in the hip region and the trunk muscles on the dominant arm side. Electromyographic signal amplitude was measured during 7 hip movements: side-lying external rotation in hip neutral position, side-lying abduction in hip neutral position, side-lying abduction in hip external rotation, side-lying abduction in hip internal rotation, prone extension in hip neutral position, prone extension in hip external rotation, and prone extension in hip internal rotation. Repeated-measures one-way analysis of variance was used to examine electromyographic activity in each of the 7 hip movements. [Results] Piriformis electromyographic activity was highest during prone hip extension in external rotation. Both the superior and inferior portions of the gluteus maximus were also highly activated during prone hip extension in external rotation. [Conclusion] Prone hip extension in external rotation induced high electromyographic activity in the piriformis and superior and inferior gluteus maximus muscles.

Effect of abduction and external rotation of the hip joint on muscle onset time during prone hip extension with knee flexion

[Purpose] This study investigated the effect of hip position on muscle onset time during prone hip extension with knee flexion. [Subjects] The study included 21 healthy male volunteers. [Methods] Muscle onset times of the right gluteus maximus, right hamstrings, bilateral lumbar erector spinae, and bilateral lumbar multifidus were measured using surface electromyography during right hip extension with knee flexion in the prone position. Measurements were made with the hip in 3 positions: (1) neutral, (2) abduction, and (3) abduction and external rotation. [Results] Gluteus maximus onset relative to the hamstrings was significantly earlier with hip abduction and with hip abduction and external rotation compared with that with the hip in the neutral position. Gluteus maximus onset relative to the hamstrings was significantly earlier with hip abduction and external rotation compared with that with hip abduction. The bilateral multifidus and left lumbar erector spinae onset times relative to the hamstrings were significantly earlier with hip abduction and external rotation compared with those with hip abduction and with the hip in the neutral position. [Conclusion] Abduction and external rotation of the hip during prone hip extension with knee flexion is effective for advancing the onset times of the gluteus maximus, bilateral multifidus, and contralateral lumbar erector spinae.