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eISSN 2287-982X

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Phys. Ther. Korea 2022; 29(2): 131-139

Published online May 20, 2022

https://doi.org/10.12674/ptk.2022.29.2.131

© Korean Research Society of Physical Therapy

어깨뼈 뒤 당김 운동 방법에 따른 큰마름근과 중간등세모근의 근두께 비의 비교

박헌미1, 김선엽2

1대전대학교 보건의료대학원 물리치료학과, 2대전대학교 보건의료과학대학 물리치료학과

Comparison of the Ratio of Thicknesses of the Rhomboid Major and Middle Trapezius Muscles While Performing Scapular Retraction Exercises

Heon-mi Park1 , PT, BHSc, Suhn-yeop Kim2 , PT, PhD

1Department of Physical Therapy, Graduate School of Health and Medicine, 2Department of Physical Therapy, College of Health and Medical Science, Daejeon University, Daejeon, Korea

Correspondence to: Suhn-yeop Kim
E-mail: kimsy@dju.kr
https://orcid.org/0000-0002-0558-7125

Received: November 11, 2021; Revised: December 9, 2021; Accepted: December 9, 2021

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background: Shoulder impingement syndrome, a major cause of shoulder pain, involves weakness of the scapular retractor muscles. The major scapular retractor muscles are the middle trapezius and rhomboid major muscles; however, the latter is excluded in most studies. Objects: We aimed to measure the thickness of the middle trapezius and rhomboid major muscles using an ultrasonic diagnostic imaging system while performing four different shoulder retraction exercises and comparing the thicknesses and ratio of the thicknesses of these muscles.
Methods: The thickness of the middle trapezius and rhomboid major muscles was measured in 24 healthy adults using ultrasound. Muscle thickness was measured three times in the Reference posture and four times while performing four different exercises that involved scapular retraction. The averages and standard deviations of the measured muscle thicknesses were obtained and compared. The ratio of muscle thickness and rate of changes in muscle thickness between the reference posture and the four exercises were compared.
Results: For both, male (n = 10) and female (n = 14), there was a significant difference in the thickness of the middle trapezius muscle between the reference posture and the four exercises (p < 0.05) and in the thickness of the middle trapezius and rhomboid major muscles between male and female (p < 0.05); however, there was no significant difference in the ratio of the thicknesses of these muscles. Although a significant difference in the rate of change in muscle thickness during the four exercises was noted, there was no significant difference in the ratio of change in muscle thickness.
Conclusion: This study demonstrates the ratio of the thicknesses of the middle trapezius and rhomboid major muscles and the rate of change in their thickness during exercises involving scapular retraction in healthy people in their 20s–30s.

Keywords: Middle trapezius, Ratio of thicknesses, Retraction exercises, Rhomboid major, Scapular

Article

Original Article

Phys. Ther. Korea 2022; 29(2): 131-139

Published online May 20, 2022 https://doi.org/10.12674/ptk.2022.29.2.131

Copyright © Korean Research Society of Physical Therapy.

어깨뼈 뒤 당김 운동 방법에 따른 큰마름근과 중간등세모근의 근두께 비의 비교

박헌미1, 김선엽2

1대전대학교 보건의료대학원 물리치료학과, 2대전대학교 보건의료과학대학 물리치료학과

Received: November 11, 2021; Revised: December 9, 2021; Accepted: December 9, 2021

Comparison of the Ratio of Thicknesses of the Rhomboid Major and Middle Trapezius Muscles While Performing Scapular Retraction Exercises

Heon-mi Park1 , PT, BHSc, Suhn-yeop Kim2 , PT, PhD

1Department of Physical Therapy, Graduate School of Health and Medicine, 2Department of Physical Therapy, College of Health and Medical Science, Daejeon University, Daejeon, Korea

Correspondence to:Suhn-yeop Kim
E-mail: kimsy@dju.kr
https://orcid.org/0000-0002-0558-7125

Received: November 11, 2021; Revised: December 9, 2021; Accepted: December 9, 2021

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background: Shoulder impingement syndrome, a major cause of shoulder pain, involves weakness of the scapular retractor muscles. The major scapular retractor muscles are the middle trapezius and rhomboid major muscles; however, the latter is excluded in most studies. Objects: We aimed to measure the thickness of the middle trapezius and rhomboid major muscles using an ultrasonic diagnostic imaging system while performing four different shoulder retraction exercises and comparing the thicknesses and ratio of the thicknesses of these muscles.
Methods: The thickness of the middle trapezius and rhomboid major muscles was measured in 24 healthy adults using ultrasound. Muscle thickness was measured three times in the Reference posture and four times while performing four different exercises that involved scapular retraction. The averages and standard deviations of the measured muscle thicknesses were obtained and compared. The ratio of muscle thickness and rate of changes in muscle thickness between the reference posture and the four exercises were compared.
Results: For both, male (n = 10) and female (n = 14), there was a significant difference in the thickness of the middle trapezius muscle between the reference posture and the four exercises (p < 0.05) and in the thickness of the middle trapezius and rhomboid major muscles between male and female (p < 0.05); however, there was no significant difference in the ratio of the thicknesses of these muscles. Although a significant difference in the rate of change in muscle thickness during the four exercises was noted, there was no significant difference in the ratio of change in muscle thickness.
Conclusion: This study demonstrates the ratio of the thicknesses of the middle trapezius and rhomboid major muscles and the rate of change in their thickness during exercises involving scapular retraction in healthy people in their 20s–30s.

Keywords: Middle trapezius, Ratio of thicknesses, Retraction exercises, Rhomboid major, Scapular

Fig 1.

Figure 1.Flow chart.
Physical Therapy Korea 2022; 29: 131-139https://doi.org/10.12674/ptk.2022.29.2.131

Fig 2.

Figure 2.Four shoulder exercise for retraction-1. (A) Resting position. (B) Horizontal abduction. (C) Shoulder extension. (D) External rotation.
Physical Therapy Korea 2022; 29: 131-139https://doi.org/10.12674/ptk.2022.29.2.131

Fig 3.

Figure 3.Four shoulder exercises for retraction-2 (shoulder extension with Y).
Physical Therapy Korea 2022; 29: 131-139https://doi.org/10.12674/ptk.2022.29.2.131

Fig 4.

Figure 4.(A) Transducer position on diagnostics ultrasound, and (B) ultrasound image of middle trapezius and rhomboids major.
Physical Therapy Korea 2022; 29: 131-139https://doi.org/10.12674/ptk.2022.29.2.131

Table 1 . General characteristics of subjects.

VariablesValueMinimumMaximum
Age (y)23.00 ± 3.721832
Sex (male/female)10/14--
Dominant side (right/left)23/1--
Height (cm)165.41 ± 10.43150185
Weight (kg)66.67 ± 17.8340115
Body mass index (kg/m2)24.07 ± 4.5916.4435.49

Values are presented as mean ± standard deviation or number. –, not available..


Table 2 . Comparison of the thickness of MT and RH according to the exercise methods.

VariablesRestingHABExtExRotExYF (p)
MTMale (n = 10)6.61 ± 2.0210.47 ± 3.21a7.77 ± 2.01b9.62 ± 3.4212.37 ± 3.45a,c4.773*
Female (n = 14)4.49 ± 1.366.61 ± 1.85a4.83 ± 1.73b6.58 ± 1.78a,c7.10 ± 2.40a,c12.505**
t2.880*3.417**3.831**2.570*4.419**
RHMale (n = 10)8.87 ± 3.4915.85 ± 3.95a11.98 ± 3.25b14.33 ± 5.6516.23 ± 5.39a3.669
Female (n = 14)5.47 ± 1.649.84 ± 3.60a7.22 ± 2.71b9.76 ± 3.01a12.07 ± 4.18a,c12.864**
t2.870*3.878**3.973**2.131*2.571*
MT/RH ratio0.83 ± 0.220.70 ± 0.190.70 ± 0.250.72 ± 0.250.71 ± 0.261.549

Values are presented mean ± standard deviation (mm). MT, middle trapezius; RH, rhomboid major; HAB, shoulder horizontal abduction; Ext, shoulder extension; ExRot, shoulder external rotation; ExY, extension with Y. aThere is a significant difference from resting. bThere is a significant difference from HAB. cThere is a significant difference from Ext. *p < 0.05, **p < 0.01..


Table 3 . Comparing the change rate of MT and RH muscle thickness according to the exercise methods.

VariablesHAB%Ext%ExRot%ExY%F
MTMale165.78 ± 53.63121.81 ± 30.60a153.58 ± 57.25198.86 ± 67.04b7.625**
Female156.51 ± 50.51111.19 ± 31.30a152.82 ± 36.62b162.23 ± 46.08b6.700**
Total160.37 ± 50.88115.61 ± 30.80a153.14 ± 45.17b177.49 ± 57.44b14.537**
RHMale204.44 ± 84.64146.67 ± 47.02184.17 ± 93.80209.34 ± 93.783.582
Female198.95 ± 93.41143.78 ± 63.42a193.72 ± 75.94b240.27 ± 102.60a,b17.851**
Total201.24 ± 87.99144.98 ± 56.04a189.74 ± 82.01b227.38 ± 98.15a,b20.239**
MT/RH% ratio0.89 ± 0.280.87 ± 0.270.90 ± 0.300.92 ± 0.470.108

Values are presented mean ± standard deviation (%). The rate of change in each movement for the resting state. MT, middle trapezius; RH, rhomboid major; HAB, shoulder horizontal abduction; Ext, shoulder extension; ExRot, shoulder external rotation; ExY, extension with Y. aThere is a significant difference from HAB%. bThere is a significant difference from Ext%. *p < 0.05, **p < 0.01..