Changes in medial elbow joint space with differences in contraction strength of flexor-pronator muscle under elbow valgus stress.
Ulnar collateral ligament
elbow valgus stress
flexor-pronator muscles
medial elbow joint space
muscle contraction strength
ultrasonography
Journal
Journal of shoulder and elbow surgery
ISSN: 1532-6500
Titre abrégé: J Shoulder Elbow Surg
Pays: United States
ID NLM: 9206499
Informations de publication
Date de publication:
Oct 2022
Oct 2022
Historique:
received:
18
01
2022
revised:
20
03
2022
accepted:
27
03
2022
pubmed:
14
5
2022
medline:
21
9
2022
entrez:
13
5
2022
Statut:
ppublish
Résumé
The relationship between contraction strength of the flexor-pronator muscles (FPMs) and elbow valgus braking function has not been clarified. The purpose of this study was to investigate changes in medial elbow joint space when there is a difference in contraction strength of FPMs under elbow valgus stress. Subjects were 20 healthy male university students, and the elbow joint on the nondominant hand side was used for measurements. The body position for limb measurement was sitting in a chair, with the shoulder abducted 60° and in 90° of external rotation, with 90° of elbow flexion. At first, maximum voluntary contraction (MVC) of the FPMs by grip motion was measured using a hand grip dynamometer under 60-N valgus stress. Contraction strengths of 10% MVC, 30% MVC, and 50% MVC were used. Ultrasonographic images of the medial elbow joint space (JS) were taken in the starting limb position. Using the Telos device system, load was then gradually increased by +10 N/s, and at the time of 60-N valgus stress, an image of the JS was taken. Furthermore, the subject adjusted to the set contraction strength (for about 5 sec) with 60-N valgus stress applied, and an image of the JS was taken while maintaining the set contraction strength. Each MVC condition (10% MVC, 30% MVC, and 50% MVC) was performed randomly. Three ultrasonographic images were taken within 10 seconds, and the average value of the three images was adopted as the JS. Compared with the JS under 60-N valgus stress, the JS was significantly reduced under 60-N valgus stress + 50% MVC. No significant difference was observed between the starting limb position and 60-N valgus stress + 50% MVC. FPMs may require muscle activity ≥50% MVC to brake 60-N elbow valgus stress.
Sections du résumé
BACKGROUND
BACKGROUND
The relationship between contraction strength of the flexor-pronator muscles (FPMs) and elbow valgus braking function has not been clarified.
HYPOTHESIS/PURPOSE
OBJECTIVE
The purpose of this study was to investigate changes in medial elbow joint space when there is a difference in contraction strength of FPMs under elbow valgus stress.
METHODS
METHODS
Subjects were 20 healthy male university students, and the elbow joint on the nondominant hand side was used for measurements. The body position for limb measurement was sitting in a chair, with the shoulder abducted 60° and in 90° of external rotation, with 90° of elbow flexion. At first, maximum voluntary contraction (MVC) of the FPMs by grip motion was measured using a hand grip dynamometer under 60-N valgus stress. Contraction strengths of 10% MVC, 30% MVC, and 50% MVC were used. Ultrasonographic images of the medial elbow joint space (JS) were taken in the starting limb position. Using the Telos device system, load was then gradually increased by +10 N/s, and at the time of 60-N valgus stress, an image of the JS was taken. Furthermore, the subject adjusted to the set contraction strength (for about 5 sec) with 60-N valgus stress applied, and an image of the JS was taken while maintaining the set contraction strength. Each MVC condition (10% MVC, 30% MVC, and 50% MVC) was performed randomly. Three ultrasonographic images were taken within 10 seconds, and the average value of the three images was adopted as the JS.
RESULTS
RESULTS
Compared with the JS under 60-N valgus stress, the JS was significantly reduced under 60-N valgus stress + 50% MVC. No significant difference was observed between the starting limb position and 60-N valgus stress + 50% MVC.
CONCLUSION
CONCLUSIONS
FPMs may require muscle activity ≥50% MVC to brake 60-N elbow valgus stress.
Identifiants
pubmed: 35550429
pii: S1058-2746(22)00426-8
doi: 10.1016/j.jse.2022.03.027
pii:
doi:
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
2011-2016Informations de copyright
Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.