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Mendez-Rebolledo G, Araya-Quintanilla F, Guzmán-Muñoz E, Salazar-Mendez J, Cruz-Montecinos C, Berckmans KR, Calatayud J. Comparative Electromyographic Study of Scapular Stabilizing Muscles During Five Main Rehabilitation Exercises. Am J Phys Med Rehabil 2024; 103:502-509. [PMID: 38261765 DOI: 10.1097/phm.0000000000002394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
OBJECTIVE The aim of the study is to compare the surface electromyographic amplitude, activation ratio, and onset latency of the main scapular stabilizing muscles between five typical rehabilitative exercises. DESIGN Twenty-seven healthy participants performed five scapular exercises (wall slide, wall push-up plus, prone horizontal abduction with external rotation, external rotation in side lying, and low row) while simultaneously recording surface electromyographic of serratus anterior, middle trapezius, lower trapezius, and upper trapezius. Surface electromyographic amplitudes, onset latencies, and activation ratios were calculated. RESULTS Prone horizontal abduction with external rotation showed an excellent upper trapezius/middle trapezius (0.43) and upper trapezius/lower trapezius (0.30) muscle balance with high (>50% maximum voluntary isometric contraction) middle trapezius and lower trapezius amplitudes, a low (<20% maximum voluntary isometric contraction) upper trapezius amplitude, and an early activation of the scapular stabilizing muscles (-474.7 to 89.9 ms) relative to upper trapezius. External rotation in side lying showed excellent upper trapezius/serratus anterior (0.26), upper trapezius/middle trapezius (0.32), and upper trapezius/lower trapezius (0.21) activation ratios and, along with low row and wall slide, showed early activation of the scapular stabilizing muscles (-378.1 to -26.6 ms). CONCLUSIONS Prone horizontal abduction with external rotation presented optimal scapular neuromuscular control. Although external rotation in side lying, low row, and wall slide did not meet all the criteria associated with optimal scapular neuromuscular control, these exercises could be used in early stages of shoulder rehabilitation because they favor early activation of the scapular stabilizing muscles.
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Affiliation(s)
- Guillermo Mendez-Rebolledo
- From the Laboratorio de Investigación Somatosensorial y Motora, Escuela de Kinesiología, Facultad de Salud, Universidad Santo Tomás, Talca, Chile (GM-R, EG-M, JS-M); Escuela de Kinesiología, Facultad de Odontología y Ciencias de la Rehabilitación, Universidad San Sebastián, Santiago, Chile (FA-Q); Department of Physical Therapy, Faculty of Medicine, University of Chile, Santiago, Chile (CC-M); Department of Rehabilitation Sciences (Physical Therapy), University Hospital Ghent, Faculty of Medicine and Health Sciences, Ghent University, Gent, Belgium (KRB); and Exercise Intervention for Health Research Group (EXINH-RG), Department of Physiotherapy, University of Valencia, Spain (JC)
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Lulic-Kuryllo T, Negro F, Jiang N, Dickerson CR. Differential regional pectoralis major activation indicates functional diversity in healthy females. J Biomech 2022; 133:110966. [DOI: 10.1016/j.jbiomech.2022.110966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 01/13/2022] [Accepted: 01/17/2022] [Indexed: 11/26/2022]
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Ehmann YJ, Berthold DP, Reuter S, Beitzel K, Köhler R, Stöcker F, Muench LN, Pogorzelski J, Rupp MC, Braun S, Imhoff AB, Buchmann S. Center of pressure (COP) measurement in patients with confirmed successful outcomes following shoulder surgery show significant sensorimotor deficits. Knee Surg Sports Traumatol Arthrosc 2022; 30:2060-2066. [PMID: 34741625 PMCID: PMC9165257 DOI: 10.1007/s00167-021-06751-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 09/16/2021] [Indexed: 11/27/2022]
Abstract
PURPOSE To determine the sensorimotor and clinical function of patients with confirmed successful outcome after either undergoing acromioclavicular joint (ACJ) stabilization, Bankart repair (BR), or rotator cuff repair (RC), and to compare these measures to the contralateral, healthy side without history of previous injuries or surgeries of the upper extremity. It was hypothesized that patients of each interventional group would have inferior sensorimotor function of the shoulder joint compared to the contralateral, healthy side, while presenting with successful clinical and functional outcomes. METHODS Three intervention groups including ten patients who had confirmed successful clinical and functional outcomes after either undergoing ACJ stabilization, BR, or RC were evaluated postoperatively at an average follow-up of 31.7 ± 11.6 months. Additionally, a healthy control group (CG) of ten patients was included. Clinical outcomes were assessed using the Constant-Murley (CM) and American Shoulder and Elbow Surgeons (ASES) Score. Pain was evaluated using the visual analogue scale (VAS). Sensorimotor function was assessed by determining the center of pressure (COP) of the shoulder joint in a one-handed support task in supine position on a validated pressure plate. RESULTS Each interventional group demonstrated excellent clinical outcome scores including the CM Score (ACJ 83.3 ± 11.8; BR 89.0 ± 10.3; RC 81.4 ± 8.8), ASES Score (ACJ 95.5 ± 7.0; BR 92.5 ± 9.6; RC 96.5 ± 5.2), and VAS (ACJ 0.5 ± 0.9; BR 0.5 ± 0.8; RC 0.5 ± 0.8). Overall, the CG showed no significant side-to-side difference in COP, whereas the ACJ-group and the BR-group demonstrated significantly increased COP compared to the healthy side (ACJ 103 cm vs. 98 cm, p = 0.049; BR: 116 cm vs. 102 cm, p = 0.006). The RC-group revealed no significant side-to-side difference (120 cm vs. 108 cm, n.s.). CONCLUSION Centre of pressure measurement detected sensorimotor functional deficits following surgical treatment of the shoulder joint in patients with confirmed successful clinical and functional outcomes. This may indicate that specific postoperative training and rehabilitation protocols should be established for patients who underwent surgery of the upper extremity. These results underline that sensorimotor training should be an important component of postoperative rehabilitation and physiotherapeutic activities to improve postoperative function and joint control. LEVEL OF EVIDENCE IV.
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Affiliation(s)
- Yannick J Ehmann
- Department of Orthopedic Sports Medicine, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany
| | - Daniel P Berthold
- Department of Orthopedic Sports Medicine, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany
| | - Sven Reuter
- Department of Orthopedic Sports Medicine, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany
- SRH University for Applied Health Sciences, Stuttgart, Germany
| | - Knut Beitzel
- Department of Orthopedic Sports Medicine, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany
- Atos Orthoparc Klinik, Cologne, Germany
| | - Robin Köhler
- Department of Orthopedic Sports Medicine, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany
| | - Fabian Stöcker
- Department of Sport and Health Sciences, TU Munich, Munich, Germany
| | - Lukas N Muench
- Department of Orthopedic Sports Medicine, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany
| | - Jonas Pogorzelski
- Department of Orthopedic Sports Medicine, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany
| | - Marco-Christopher Rupp
- Department of Orthopedic Sports Medicine, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany
| | - Sepp Braun
- Department of Orthopedic Sports Medicine, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany
- Gelenkpunkt, Sport and Joint Surgery Innsbruck, Innsbruck, Austria
- OSMI - Research Unit for Orthopaedic Sports Medicine and Injury Prevention, UMIT - Private University for Health Sciences, Medical Informatics and Technology, Hall, Austria
| | - Andreas B Imhoff
- Department of Orthopedic Sports Medicine, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany.
| | - Stefan Buchmann
- Department of Orthopedic Sports Medicine, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany
- OFZ Weilheim, Weilheim, Germany
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Whittaker RL, Alenabi T, Kim SY, Dickerson CR. Regional Electromyography of the Infraspinatus and Supraspinatus Muscles During Standing Isometric External Rotation Exercises. Sports Health 2021; 14:725-732. [PMID: 34657490 PMCID: PMC9460097 DOI: 10.1177/19417381211043849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Whole-muscle electromyography (EMG) data of the rotator cuff support external rotation (ER) strengthening exercises during shoulder rehabilitation. However, distinct neuroanatomic regions in the supraspinatus and infraspinatus exist. Differences in regional muscle activity occur during rehabilitation exercises, but little information is available for ER exertions. HYPOTHESIS Regional infraspinatus and supraspinatus muscle activity during standing ER exertions will differ with posture and intensity. STUDY DESIGN Descriptive laboratory study. LEVEL OF EVIDENCE Level 5. METHODS Twenty healthy individuals (12 men, 8 women) participated. Fine wire electrodes were inserted into 2 supraspinatus and 3 infraspinatus muscle regions. EMG data were recorded during standing isometric ER exertions at 2 intensities (maximal, submaximal) and in 7 postures defined by the angle (0°, 30°, 90°) and plane (abduction, scaption, flexion) of arm elevation. EMG data were normalized to maximum voluntary isometric contraction (% MVIC) to examine the influences of posture, intensity and their interaction on muscle activity. RESULTS Superior infraspinatus activity was higher in 0° of elevation (50.9% ± 5.7% MVIC) versus 30° of flexion (37.4% ± 3.9% MVIC) at maximal intensity. Inferior infraspinatus activity was higher in 90° of scaption (max = 59.8% ± 2.8% MVIC, submax = 29.4% ± 1.9% MVIC) versus 0° of elevation (max = 42.3% ± 4.5% MVIC, submax = 22.4% ± 2.8% MVIC) (P = 0.02, P = 0.05, respectively). Anterior supraspinatus activity was highest in 90° of adbuction (max = 61.6% ± 3.1% MVIC; submax = 39.1% ± 3.8% MVIC) and lowest in 30° of flexion (max = 29.0% ± 3.4% MVIC, submax = 15.6% ± 1.7% MVIC) and 90° of flexion (max = 34.6% ± 2.4% MVIC, submax = 14.8% ± 1.9% MVIC). Posterior suprasptinatus activity was lowest in 0° of elevation (34.2% ± 3.0% MVIC), 30° of flexion (33.0% ± 3.6% MVIC) and highest in 90° of abduction (56.2% ± 4.1% MVIC) and 90° of scaption (46.7% ± 2.8% MVIC) (all Ps < 0.04). CONCLUSION Regional infraspinatus and supraspinatus muscle activity differed with posture and intensity. Superior and middle infraspinatus muscle activities were similar across postures, but inferior infraspinatus activity was highest in 90° of arm elevation. Anterior and posterior supraspinatus activities were higher in the abduction and scaption planes, especially at 90° of elevation, as compared with the flexion plane. CLINICAL RELEVANCE In shoulder rehabilitation of supraspinatus tendon injuries, ER exercises in the flexion plane challenge the whole infraspinatus muscle and require lower supraspinatus muscle activity.
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Affiliation(s)
- Rachel L Whittaker
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Talia Alenabi
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Soo Y Kim
- School of Physical Therapy, College of Medicine, University of Saskatchewan, Saskatoon, Canada
| | - Clark R Dickerson
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
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Zaluski AJ, Campbell J, Hlasny M, Nedjelski M, Thompson T, Vanneste A, Kim SY. Activation of neuromuscular sub-regions of supraspinatus and infraspinatus during common rehabilitative exercises. J Electromyogr Kinesiol 2021; 61:102604. [PMID: 34587575 DOI: 10.1016/j.jelekin.2021.102604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 09/11/2021] [Accepted: 09/15/2021] [Indexed: 11/30/2022] Open
Abstract
'Regional activation' has been identified within the supraspinatus and infraspinatus. Previous EMG studies have provided insight on the different functions of the sub-regions within the supraspinatus and infraspinatus, however, to date timing of peak EMG activation has not been investigated. To assess how theses sub-regions function during commonly prescribed rehabilitation exercises, electrodes were inserted into the supraspinatus - anterior and posterior- and infraspinatus - superior and middle - of 22 healthy participants. For each sub-region, normalized EMG data - amplitude and timing - was collected from nine rehabilitation exercises - three with an elastic band and six an exercise ball. Supraspinatus posterior and infraspinatus superior had similar activation levels between elastic band exercises, but the timing of peak activation was exercise specific. In all elastic band exercises, supraspinatus posterior activated prior to supraspinatus anterior. All ball exercises elicited low-amplitude muscle activation; dynamic ball exercises had higher peak muscle activation than their static counterparts.
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Affiliation(s)
- Alexandra J Zaluski
- School of Rehabilitation Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Jeremy Campbell
- School of Rehabilitation Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Magda Hlasny
- School of Rehabilitation Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Mason Nedjelski
- School of Rehabilitation Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Tanner Thompson
- School of Rehabilitation Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Alex Vanneste
- School of Rehabilitation Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Soo Y Kim
- School of Rehabilitation Sciences, University of Saskatchewan, Saskatoon, Canada.
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Berckmans KR, Castelein B, Borms D, Parlevliet T, Cools A. Rehabilitation Exercises for Dysfunction of the Scapula: Exploration of Muscle Activity Using Fine-Wire EMG. Am J Sports Med 2021; 49:2729-2736. [PMID: 34279126 DOI: 10.1177/03635465211025002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Scapular muscle activity during shoulder exercises has been explored with surface electromyography (EMG). However, knowledge about the activity of deeper-layer scapular muscles is still limited. PURPOSE To investigate EMG activation of the deeper-layer scapular stabilizers (levator scapulae [LS], rhomboid major [RM], pectoralis minor [Pm] muscles) together with superficial muscle activity (upper [UT], middle [MT], and lower trapezius [LT] and serratus anterior [SA]) during 4 exercises often used for training scapular function. Based on the amplitude EMG of the deeper-layer muscles, scapular muscle activation ratios for the 4 exercises were calculated, hereby providing knowledge of the optimal muscle balance. STUDY DESIGN Descriptive laboratory study. METHODS A total of 26 healthy participants performed 4 shoulder exercises (side-lying external rotation [ER], side-lying forward flexion, prone horizontal abduction with ER, and prone extension) while simultaneously measuring scapular muscle activity. Intramuscular electrodes were used for the deeper layer, in contrast to surface electrodes for the superficial muscles. All data were normalized to percentage of maximal voluntary isometric contraction (%MVIC), and the activation ratios (the muscle activity of the deeper layer relative to the other muscles) were calculated. A 1-way analysis of variance with Bonferroni correction was applied for statistical analysis. RESULTS Moderate activity was found in all exercises for the LS and RM (25%-45% MVIC). The Pm resulted in low activity during both side-lying exercises (13%-18% MVIC). Ratios involving LS or RM showed values >1 for all exercises (1.28-12.41) except for LS/MT, LS/LT, and LS/RM (0.85-0.98) during side-lying ER, and LS/MT, RM/MT and RM/LS (0.85-0.99) during side-lying forward flexion. Likewise, values <1 were found when MT (0.85) and LS (0.99) were involved with RM in the numerator during side-lying forward flexion. Ratios with Pm in the numerator showed values <1, apart from the ratios with UT and SA in the denominator. CONCLUSION The study provides extended knowledge about the deeper-layer scapular muscle activity and related ratios during the 4 shoulder exercises mentioned here. Putting theory into practice, based on our results, we advise both side-lying exercises to be performed to strengthen LT and MT, even in case of hyperactivity of the Pm. However, the 4 exercises should be given carefully to patients with hyperactivity in the LS and/or RM. CLINICAL RELEVANCE The findings of this study may assist clinical decision making in exercise selection for restoring scapular function.
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Affiliation(s)
- Kelly R Berckmans
- Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Birgit Castelein
- Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Dorien Borms
- Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Thierry Parlevliet
- Physical Medicine and Orthopedic Surgery, Faculty of Medicine, University Hospital Ghent, Ghent, Belgium
| | - Ann Cools
- Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
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Bench RW, Thompson SE, Cudlip AC, Holmes MW. Examining Muscle Activity Differences During Single and Dual Vector Elastic Resistance Exercises. Int J Sports Phys Ther 2021; 16:322-334. [PMID: 33842028 PMCID: PMC8016432 DOI: 10.26603/001c.21309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 10/20/2020] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Elastic resistance exercise is a common part of rehabilitation programs. While these exercises are highly prevalent, little information exists on how adding an additional resistance vector with a different direction from the primary vector alters muscle activity of the upper extremity. PURPOSE The purpose of this study was to examine the effects of dual vector exercises on torso and upper extremity muscle activity in comparison to traditional single vector techniques. STUDY DESIGN Repeated measures design. METHODS Sixteen healthy university-aged males completed four common shoulder exercises against elastic resistance (abduction, flexion, internal rotation, external rotation) while using a single or dual elastic vector at a fixed cadence and standardized elastic elongation. Surface electromyography was collected from 16 muscles of the right upper extremity. Mean, peak and integrated activity were extracted from linear enveloped and normalized data and a 2-way repeated measures ANOVA examined differences between conditions. RESULTS All independent variables differentially influenced activation. Interactions between single/dual vectors and exercise type affected mean activation in 11/16 muscles, while interactions in peak activation existed in 7/16 muscles. Adding a secondary vector increased activation predominantly in flexion or abduction exercises; little changes existed when adding a second vector in internal and external rotation exercises. The dual vector exercise in abduction significantly increased mean activation in lower trapezius by 25.6 ± 8.11 %MVC and peak activation in supraspinatus by 29.4 ± 5.94 %MVC (p<0.01). Interactions between single/dual vectors and exercise type affected integrated electromyography for most muscles; the majority of these muscles had the highest integrated electromyography in the dual vector abduction condition. CONCLUSION Muscle activity often increased with a second resistance vector added; however, the magnitude was exercise-dependent. The majority of these changes existed in the flexion and abduction exercises, with little differences in the internal or external rotation exercises. LEVEL OF EVIDENCE 3b.
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Hoshikawa K, Yuri T, Giambini H, Kiyoshige Y. Shoulder scaption is dependent on the behavior of the different partitions of the infraspinatus muscle. Surg Radiol Anat 2021; 43:653-659. [PMID: 33464394 PMCID: PMC8105206 DOI: 10.1007/s00276-020-02674-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 12/30/2020] [Indexed: 01/06/2023]
Abstract
Purpose The purpose of this study was to investigate if the three partitions (superior, middle, and inferior partitions) of the infraspinatus muscle previously described in anatomical studies will present different behavior during scapular plane abduction (scaption) as described using shear-wave elastography, especially during initial range of motion. Methods Eight volunteers held their arm against gravity 15° intervals from 30° to 150° in scaption. Shear-wave elastography was implemented at each position to measure shear modulus at rest and during muscle contraction, as a surrogate for muscle stiffness, of each partition. Muscle activity was defined as the difference in stiffness values between the resting positions and those during muscle contraction (ΔE = stiffness at contraction—stiffness at rest). Results The activity value for the middle partition was 25.1 ± 10.8 kPa at 30° and increased up to 105° (52.2 ± 10.8 kPa), with a subsequent decrease at larger angle positions (p < .001). The superior partition showed a flatter and constant behavior with smaller activity values except at higher angles (p < .001). Peak activity values for the superior partition were observed at 135° (23.0 ± 12.0 kPa). Increase activity for inferior partition began at 60° and showed a peak at 135° (p < .001; 32.9 ± 13.8 kPa). Conclusion Stiffness measured using shear-wave elastography in each partition of the infraspinatus muscle demonstrated different behavior between these partitions during scaption. The middle partition generated force throughout scaption, while the superior and inferior partitions exerted force at end range.
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Affiliation(s)
- Kyosuke Hoshikawa
- Department of Physical Therapy, Yamagata Prefectural University of Health Sciences, Yamagata, Japan
| | - Takuma Yuri
- Graduate School of Health Sciences, Yamagata Prefectural University of Health Sciences, Yamagata, Japan.
- Department of Biomedical Engineering, The University of Texas at San Antonio, San Antonio, TX, USA.
| | - Hugo Giambini
- Department of Biomedical Engineering, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Yoshiro Kiyoshige
- Department of Physical Therapy, Yamagata Prefectural University of Health Sciences, Yamagata, Japan
- Graduate School of Health Sciences, Yamagata Prefectural University of Health Sciences, Yamagata, Japan
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Do surface electrodes validly represent lower trapezius activation patterns during shoulder tasks? J Electromyogr Kinesiol 2020; 53:102427. [PMID: 32470865 DOI: 10.1016/j.jelekin.2020.102427] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 02/27/2020] [Accepted: 05/07/2020] [Indexed: 11/21/2022] Open
Abstract
Because of its superficial location, surface electrodes are commonly used to record lower trapezius activity. Recent evidence, however, would suggest that surface electromyography is not a valid to record activity from other superficially placed shoulder muscles. Therefore, the aim of this study was to determine the validity of using surface electrodes to record lower trapezius activity. Ten asymptomatic subjects performed ramped isometric (0-100% maximum load) and dynamic (70% maximum load) shoulder tasks. Intramuscular electrodes were inserted into lower trapezius and rhomboid major. Surface electrodes were placed over lower trapezius around the intramuscular electrodes. Differences in the recorded activity of lower trapezius between surface and intramuscular electrodes were tested using a 2 factor repeated measures analysis of variance with factors: test and electrode type. Similarity in the recorded activity patterns between the two electrodes was tested using Pearson's correlation coefficient (r). Results indicated that there was no difference in lower trapezius activity levels (p = 0.98) or activation patterns (r ≥ 0.74) recorded by the intramuscular and surface electrodes. The results of this study indicate that any potential crosstalk contamination in the surface electrode signal is having little influence on the recorded activity from lower trapezius and therefore, support the common practice of surface electromyography to investigate lower trapezius function.
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Tsuruike M, Ellenbecker TS, Lauffenburger C. The Application of Double Elastic Band Exercise in the 90/90 Arm Position for Overhead Athletes. Sports Health 2020; 12:495-500. [PMID: 32720852 DOI: 10.1177/1941738120935441] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Traditional exercises performed with the shoulder in the position of 90° abduction and external rotation with elbow flexion (90/90) while using a single elastic band showed moderate activity of both the lower trapezius (LT) and infraspinatus (IS) muscle. The purpose of this study was to investigate activity of the teres minor (TMi) and the LT muscles during standing external rotation exercise with the shoulder in the 90/90 position with 2 elastic bands in both the frontal and the scapular plane. HYPOTHESIS TMi, IS, and LT muscle activities will vary depending on whether the shoulder is positioned in the frontal or scapular plane with the application of 2 elastic bands. Also, the serratus anterior (SA) and teres major (TMa) muscles will produce different muscular activity patterns during exercises performed with 2 elastic bands in the frontal plane compared with the TMi and LT muscles. STUDY DESIGN Controlled laboratory study. LEVEL OF EVIDENCE Level 4. METHODS A total of 21 collegiate baseball players volunteered to participate. The electromyography (EMG) activities of the TMi, IS, LT, SA, TMa, middle deltoid (MD), posterior deltoid, and upper trapezius (UT) muscles were measured with the 90/90 arm position during both isometric and oscillation resistance exercises with 2 elastic bands oriented in the frontal and scapular planes. RESULTS A significant difference was observed in EMG activity of both the TMi and the LT muscles between single and double elastic band applications in the frontal plane (P < 0.05). In contrast, EMG activity of the IS, SA, and TMa muscles was significantly increased in the scapular plane compared with the frontal plane (P < 0.05). CONCLUSION The standing 90/90 position effectively increased both TMi and LT muscle EMG activity with the double elastic band in the frontal plane while minimizing UT and MD muscle activity. EMG activity of the IS, SA, and TMa muscles increased with exercise in the scapular plane as compared with the frontal plane. CLINICAL RELEVANCE Oscillation movement under double elastic band application differentiated external rotator muscle and scapular muscle activities between the frontal and scapular plane during the 90/90 exercise in the frontal plane compared with the scapular plane. Clinicians can utilize each of the scapular and frontal positions based on their desired focus for muscular activation.
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Affiliation(s)
- Masaaki Tsuruike
- Department of Kinesiology, College of Health and Human Sciences, San José State University, San Jose, California, and
| | | | - Connor Lauffenburger
- Department of Kinesiology, College of Health and Human Sciences, San José State University, San Jose, California, and
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