Phys. Ther. Korea 2023; 30(3): 245-252
Published online August 20, 2023
https://doi.org/10.12674/ptk.2023.30.3.245
© Korean Research Society of Physical Therapy
Joo-young Jeon1 , PT, BPT, Jun-hee Kim2
, PT, PhD, Oh-yun Kwon2,3
, PT, PhD
1Department of Physical Therapy, The Graduate School, Yonsei University, 2Kinetic Ergocise Based on Movement Analysis Laboratory, 3Department of Physical Therapy, College of Software and Digital Healthcare Convergence, Yonsei University, Wonju, Korea
Correspondence to: Oh-yun Kwon
E-mail: kwonoy@yonsei.ac.kr
https://orcid.org/0000-0002-9699-768X
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.
Background: Various functional tests such as upper quarter Y-balance test (UQYBT) are used to evaluate shoulder stability and mobility in clinical or sports fields. Previous studies have been conducted to determine the correlation between the scapular or trunk muscle and UQYBT. However, the correlation between UQYBT and hip flexor, which can be considered as a core muscle, has not been confirmed. Objects: To verify the relationship between the UQYBT and scapular muscle (scapular protractor and lower trapezius [LT]), trunk muscle, and hip flexor strengths in healthy male participants.
Methods: A total of 37 healthy male participants were recruited and underwent UQYBT in the push-up posture. The isometric strength of the scapular protractor, LT, trunk flexor and extensor, and hip flexors were measured using a smart KEMA strength sensor (KOREATECH Inc.).
Results: The superolateral direction of the UQYBT was moderately to strongly related to trunk extensor (r = 0.443, p < 0.01), scapular protractor (r = 0.412, p < 0.05), LT (r = 0.436, p < 0.01), and both sides of the hip flexors (supporting-side: r = 0.669, p < 0.01; non-supporting- side: r = 0.641, p < 0.01). The inferolateral direction of the UQYBT was moderately related to the scapular protractor (r = 0.429, p < 0.01), LT (r = 0.511, p < 0.01), and both sides of hip flexors (supporting-side: r = 0.481, p < 0.01; non-supporting-side: r = 0.521, p < 0.01). The medial direction of the UQYBT was moderately to strongly related with the scapular protractor (r = 0.522, p < 0.01), LT (r = 0.541, p < 0.01), and both sides of hip flexors (supporting-side: r = 0.605, p < 0.01; non-supporting-side: r = 0.561, p < 0.01).
Conclusion: This study showed that the strength of the scapular muscles, trunk muscles, and hip flexor muscles correlated to the UQYBT. Therefore, the strength of not only the scapular and trunk muscles but also the hip flexor muscles should be considered to improve the UQYBT.
Keywords: Muscle strength, Physical examination, Psoas muscle
Phys. Ther. Korea 2023; 30(3): 245-252
Published online August 20, 2023 https://doi.org/10.12674/ptk.2023.30.3.245
Copyright © Korean Research Society of Physical Therapy.
Joo-young Jeon1 , PT, BPT, Jun-hee Kim2
, PT, PhD, Oh-yun Kwon2,3
, PT, PhD
1Department of Physical Therapy, The Graduate School, Yonsei University, 2Kinetic Ergocise Based on Movement Analysis Laboratory, 3Department of Physical Therapy, College of Software and Digital Healthcare Convergence, Yonsei University, Wonju, Korea
Correspondence to:Oh-yun Kwon
E-mail: kwonoy@yonsei.ac.kr
https://orcid.org/0000-0002-9699-768X
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.
Background: Various functional tests such as upper quarter Y-balance test (UQYBT) are used to evaluate shoulder stability and mobility in clinical or sports fields. Previous studies have been conducted to determine the correlation between the scapular or trunk muscle and UQYBT. However, the correlation between UQYBT and hip flexor, which can be considered as a core muscle, has not been confirmed. Objects: To verify the relationship between the UQYBT and scapular muscle (scapular protractor and lower trapezius [LT]), trunk muscle, and hip flexor strengths in healthy male participants.
Methods: A total of 37 healthy male participants were recruited and underwent UQYBT in the push-up posture. The isometric strength of the scapular protractor, LT, trunk flexor and extensor, and hip flexors were measured using a smart KEMA strength sensor (KOREATECH Inc.).
Results: The superolateral direction of the UQYBT was moderately to strongly related to trunk extensor (r = 0.443, p < 0.01), scapular protractor (r = 0.412, p < 0.05), LT (r = 0.436, p < 0.01), and both sides of the hip flexors (supporting-side: r = 0.669, p < 0.01; non-supporting- side: r = 0.641, p < 0.01). The inferolateral direction of the UQYBT was moderately related to the scapular protractor (r = 0.429, p < 0.01), LT (r = 0.511, p < 0.01), and both sides of hip flexors (supporting-side: r = 0.481, p < 0.01; non-supporting-side: r = 0.521, p < 0.01). The medial direction of the UQYBT was moderately to strongly related with the scapular protractor (r = 0.522, p < 0.01), LT (r = 0.541, p < 0.01), and both sides of hip flexors (supporting-side: r = 0.605, p < 0.01; non-supporting-side: r = 0.561, p < 0.01).
Conclusion: This study showed that the strength of the scapular muscles, trunk muscles, and hip flexor muscles correlated to the UQYBT. Therefore, the strength of not only the scapular and trunk muscles but also the hip flexor muscles should be considered to improve the UQYBT.
Keywords: Muscle strength, Physical examination, Psoas muscle
Table 1 . Participants’ characteristics.
Variable | Male (N = 37) |
---|---|
Age (y) | 27.54 ± 6.20 |
Height (cm) | 174.76 ± 6.45 |
Weight (kg) | 76.89 ± 12.36 |
Values are presented as mean ± standard deviation..
Table 2 . Isometric muscle strength and each direction score and a composite score of UQYBT.
Variable | Male (N = 37) |
---|---|
Muscle strength (%bw) | |
Supporting-side scapular protractor | 21.04 ± 8.72 |
Supporting-side lower trapezius | 8.97 ± 3.66 |
Supporting-side hip flexor | 19.78 ± 6.91 |
Non-supporting-side hip flexor | 18.19 ± 6.83 |
Trunk flexor | 16.75 ± 6.43 |
Trunk extensor | 33.65 ± 11.69 |
UQYBT score (%AL) | |
Medial | 108.00 ± 9.80 |
Superolateral | 58.94 ± 13.17 |
Inferolateral | 70.38 ± 12.69 |
Composite score | 79.26 ± 9.97 |
Values are presented as mean ± standard deviation. UQYBT, upper quarter Y-balance test; bw, body weight; AL, arm length..
Table 3 . Correlation between isometric strength and upper quarter Y-balance test.
Supporting-side scapular protractor | Supporting-side lower trapezius | Non-supporting-side hip flexor | Supporting-side hip flexor | Trunk flexor | Trunk extensor | |
---|---|---|---|---|---|---|
Medial direction | 0.522** | 0.541** | 0.561** | 0.605** | 0.232 | 0.261 |
Superolateral direction | 0.412* | 0.436** | 0.641** | 0.669** | 0.379* | 0.443** |
Inferolateral direction | 0.429** | 0.511** | 0.521** | 0.481** | 0.171 | 0.250 |
Composite score | 0.521** | 0.567** | 0.664** | 0.678** | 0.302 | 0.368* |
Values are presented as r value. *p < 0.05, **p < 0.01..