Elsevier

Physical Therapy in Sport

Volume 22, November 2016, Pages 35-40
Physical Therapy in Sport

Original research
Comparison of gluteus maximus and hamstring electromyographic activity and lumbopelvic motion during three different prone hip extension exercises in healthy volunteers

https://doi.org/10.1016/j.ptsp.2016.03.004Get rights and content

Highlights

  • Muscle activity of the gluteus maximus (GM) was measured during three different PHE exercises.

  • The kinematic data for rotation or anterior tilting angle of the pelvis were measured.

  • Prone table hip extension with 90° knee flexion (PTHEK) was an effectively modified exercise.

  • Finding suggested that the PTHEK can be recommended as an effective method to strengthen GM.

Abstract

Objective

To compare the surface electromyography (EMG) amplitude of the hip joint, including the gluteus maximus (GM), biceps femoris (BF), and semitendinosus (ST) muscles generated by three different exercises: prone hip extension (PHE), prone table hip extension (PTHE), and prone table hip extension with 90° knee flexion (PTHEK), with compensatory pelvic motions.

Design

Repeated-measure within-subject intervention.

Participants

Sixteen-healthy males (mean age = 23.4 ± 2.2 years).

Main outcome measures

EMG was used to collect EMG signals from the GM, erector spinae (ES), BF, and ST muscles. Furthermore an electromagnetic tracking motion analysis was also performed to measure the compensations.

Results

EMG amplitude differed significantly among the three conditions (PHE vs. PTHE vs. PTHEK) (p < 0.05). The mean GM muscle activity increased significantly during the PTHEK (70.93% and 13.75% increases in %MVIC compared with the PHE and PTHE, respectively) (p < 0.01). However, there was no significant difference in the kinematic data for rotation or anterior tilting angle of the pelvis among the three conditions (p > 0.05).

Conclusions

These results suggest that the PTHEK can be recommended as an effective method to strengthen the GM muscle without increased BF or ES muscle activities and without compensatory pelvic motions.

Introduction

Active prone hip extension (PHE) is a strengthening exercise for individuals with some form of weakness in their hip joint muscles (Tateuchi, Taniguchi, Mori, & Ichihashi, 2012). Furthermore, measuring the stability of the lumbopelvic region can be accomplished through PHE (Janda, 1996, Sahrmann, 2002). In addition, previous studies have stated that PHE can be used to evaluate lumbo-pelvic-hip joint muscle activation (Ebrall, 2004, Greenman, 2003, Hertling and Kessler, 2006, Janda, 1996). Sahrmann (2002) reported that individuals with lumbopelvic instability have limitations in controlling excessive extension and rotation of the lumbar spine and anterior tilt and rotation of the pelvis during PHE. Interestingly, over-activity of the erector spinae and hamstring muscles, along with a decreased activation of the gluteus maximus (GM) muscle, has been explained as being due to a change in the activation pattern in these muscles, which can cause movement dysfunction (Janda, 1996, Sahrmann, 2002).

The PHE exercise is one of the primary conventional interventions in rehabilitation to strengthen the GM (Cappozzo et al., 1985, Wilson et al., 2005). Kendall, McCreary, and Provance (2005) recommended PHE incorporating a minimum knee flexion of 90° with resistance against the lower part of the posterior thigh for promoting GM strength. However, a modified test of GM strength is used for individuals possessing low back muscle (i.e. extensor) weakness and/or hip flexor tightness. Specifically, individuals lie on a table with their trunk in the prone position and legs hanging over the end of the table (Kendall et al., 2005). For example, Kang, Jeon, Kwon, Cynn, and Choi (2013) reported that PHE in 90° flexion and 30° hip abduction can lead to maximal GM and minimal hamstring activity versus the 0° hip abduction position. Yoon, Lee, and An (2015) reported that PHE initiated at hip flexion of 20° contributed to greater GM and lower biceps femoris (BF) muscle activities compared with 0° and 45° hip flexion. In addition, Lewis and Sahrmann (2009) reported that muscle activation and movement patterns can be modified by providing verbal cues during the performance of the modified PHE from 30° of hip flexion to neutral.

Comerford and Mottram (2012) proposed that the prone table hip extension test (PTHE) to co-activate the GM and abdominal muscles, which are used to control the lumbar spine and pelvis. Specifically, this test can be performed while the trunk is supported on the table, with both feet placed firmly on the floor, and with the lumbar spine in a neutral position. However, some modified PHE exercises may cause extension and rotation of the lumbar spine, as well as anterior tilting and rotation of the pelvis in compensation if the lumbopelvic region is not stabilized (Comerford and Mottram, 2012, Sahrmann, 2002). Similarly, incorrect exercises for GM strengthening may lead to increased unwanted adjacent muscle activation. Therefore, exercises that decrease muscle activation of the BF and erector spinae (ES) and that selectively strengthen the GM, may be crucially important. Several previous studies have used a pressure bio-feedback unit (PBU) to minimize the lumbopelvic compensation movement using the ‘abdominal drawing in maneuver’ (ADIM) during lower-extremity exercises (Chance-Larsen et al., 2010, Oh et al., 2006). However, no literature has compared GM, BF, semitendinosus (ST), and ES activities and compensatory lumbopelvic motion during the three different PHE exercises in healthy participants.

Therefore, the purpose of this study was to compare the muscle amplitudes of the lumbo-pelvic-hip complex, including the ES, GM, BF, and ST muscles and lumbopelvic motions, during performance of three different PHE exercises: the ‘conventional’ PHE, PTHE, and PTHE with knee flexion (PTHEK). We hypothesize that the muscle activity of GM would be significantly greater in PTHEK compared with conventional PHE and PTHE. Furthermore, by comparing these different PHE exercises, we suggest that GM muscles can be progressively strengthened in advanced rehabilitation programs in both open and closed chain positions.

Section snippets

Participants

The G*power software was used to estimate sample size (ver. 3.1.2; Franz Faul, University of Kiel, Kiel, Germany) in a pilot study of five participants. A priori calculation of sample size was carried out with a power of 0.80, an alpha level of 0.05, and effect size of 1.58. This result indicated that the necessary sample size was at least six participants for the study. Sixteen healthy male participants (mean ± SD; age = 23.4 ± 2.2 years; body mass = 69.1 ± 7.1 kg; height = 176.7 ± 3.8 cm)

EMG amplitude

The ES, GM, BF, and ST EMG amplitudes on the dominant side of the body were significantly different between the three prone hip extension exercises (p < 0.01; Table 1). The post hoc comparison revealed that the GM EMG amplitude was greatest in the PTHEK exercise, followed by PTHE and then PHE (mean ± SD: 55 ± 18%MVIC, 47 ± 25%MVIC, and 16 ± 12%MVIC, respectively; padj < 0.001) (Fig. 2). Furthermore, the BF and ST amplitudes in the PTHE were significantly greater than those in the PHE and PTHEK

Discussion

Strengthening exercises for the GM are important for individuals with hip weakness, for rehabilitation purposes. However, most of the clinical GM strengthening exercises are not commonly used with consideration of the exercise position during a rehabilitation program. In addition, a variety of compensations in the lower back and pelvic regions may occur frequently in individuals with poor movement control during hip movements (Sahrmann, 2002, Van Dillen et al., 2008). Therefore, this study

Limitations

Firstly, the placement of the electrodes for the surface EMG could be seen as a limitation due to the possibility of crosstalk between the BF and ST muscles. Secondly, we did not measure the EMG amplitude from any specific abdominal muscle due to the nature of the exercise positions. The PBU was used to confirm ADIM. However, we did not confirm whether ADIM was performed by participants correctly for activating lower abdominal muscles using ultrasonography. Third, our results, which were

Conclusions

The purpose of this study was to compare the EMG amplitude of the muscles of the lumbo-pelvic-hip complex, including the GM, BF, and ST muscles, during the PHE, PTHE, and PTHEK exercises. We found that the GM EMG amplitude was greatest and the BF EMG amplitude was smallest during the PTHEK, compared with the PHE and PTHE. We suggest that the PTHEK exercise may be helpful in an advanced rehabilitation program to intensively activate the GM muscle, while inhibiting the BF muscle, which

Conflict of interest

None declared.

Ethical approval

The protocols of this study were approved by the Yonsei University Wonju Campus Human Studies Committee in January 2015. The management number in protocols of this study is 1041849-201411-BM-052-02.

Funding

None declared.

Acknowledgment

I want to express my deep appreciation for those who have been willing to give me valuable help. If they had not given me any support, I could have never finished this paper. In addition, I wish to express sincerely appreciation to all voluntary participants in the study.

The authors would like to acknowledge financial and administrative supports provided from “Brain Korea 21 Project (grant number: 2016-51-0009)” sponsored by the Korean Research Foundation.

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