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Lee JH, Lee KW, Yi KH, Choi YJ, Hu HW, Lee HJ. A standardized protocol for needle placement in the infraspinatus muscle: an anatomical perspective. Surg Radiol Anat 2023; 45:1579-1586. [PMID: 37773544 DOI: 10.1007/s00276-023-03245-1] [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: 05/17/2023] [Accepted: 09/07/2023] [Indexed: 10/01/2023]
Abstract
PURPOSE This study aimed to evaluate the morphology of the three parts of the infraspinatus muscle based on surface landmarks for precise and effective access, and to propose the most effective fine-wire electrode insertion technique and sites. METHODS Fifteen Asian fresh cadavers were used. We investigated the probability of the presence of the superior, middle, and inferior parts in each infraspinatus muscle based on surface landmarks. Based on the positional characteristics of the muscle, we determined the needle insertion method and confirmed its effectiveness by dissection. RESULTS The superior part was mostly observed near the spine of the scapula. The middle part was broadly observed within the infraspinous fossa. The inferior part showed variable location within the infraspinous fossa. The injection accuracy of the superior, middle, and inferior parts in the infraspinatus muscle was 95.8%, 100%, and 91.7%, respectively. Targeting the superior and middle parts for injection of the infraspinatus muscle is relatively more straightforward than targeting the inferior part. Targeting the inferior part of the infraspinatus muscle in this study was more challenging than targeting the superior and middle parts. CONCLUSION Needling for electromyography should be performed with special care to avoid unintended muscle parts, which could lead to inaccurate data acquisition and affect the conclusions about muscle function.
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Affiliation(s)
- Ji-Hyun Lee
- Department of Anatomy and Acupoint, College of Korean Medicine, Gachon University, Seongnam, 13120, Republic of Korea
| | - Kang-Woo Lee
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Human Identification Research Institute, BK21 FOUR Project, Yonsei University College of Dentistry, Seoul, 03722, Republic of Korea
| | - Kyu-Ho Yi
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Human Identification Research Institute, BK21 FOUR Project, Yonsei University College of Dentistry, Seoul, 03722, Republic of Korea
- Maylin Clinic (Apgujeong), Seoul, Republic of Korea
| | - You-Jin Choi
- Department of Anatomy, School of Medicine, Konkuk University, Chungju, 27478, South Korea
| | - Hye-Won Hu
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Human Identification Research Institute, BK21 FOUR Project, Yonsei University College of Dentistry, Seoul, 03722, Republic of Korea
| | - Hyung-Jin Lee
- Catholic Institute for Applied Anatomy, Department of Anatomy, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul, 06591, Republic of Korea.
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Calver R, Cudlip A, Dickerson CR, Mondal P, Butcher S, Kim SY. A comparison of isometric and isokinetic normalization methods for electromyographic data from sub-regions of supraspinatus and infraspinatus during dynamic tasks. Int Biomech 2023; 10:1-9. [PMID: 37183477 DOI: 10.1080/23335432.2023.2210634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023] Open
Abstract
This study explored effects of using isometric versus isokinetic maximal voluntary contractions (MVCs) to normalize EMG data from supraspinatus and infraspinatus subregions during isokinetic tasks. Participants performed submaximal isokinetic external rotation (ER) and scaption tasks at two speeds. Three isometric MVCs were used: seated ER; side-lying scaption; side-lying abduction. Isokinetic MVCs were performed in the same position and speeds as the experimental tasks. Data were normalized using peak EMG from reference tasks: MVC which produced the greatest amplitude overall (MEA), isometric MVC with greatest amplitude (isometric best), isokinetic MVC with greatest amplitude (isokinetic best), and the greatest amplitude from the isokinetic MVC that matched the experimental task (isokinetic matched). Mean %MVC from each experimental task/ sub-region were compared by normalization method. The isokinetic matched method versus the MEA method was significantly different in all comparisons with isokinetic matched resulting in relative normalized task values up to 162% greater. The isometric best method resulted in significantly greater %MVC 37% of the time compared to the MEA method, whereas there were no differences when using isokinetic best compared to MEA. Isokinetic MVCs are less likely to overestimate %MVC than isometric and their use should be considered when normalizing data from dynamic tasks.
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Affiliation(s)
- Ronelle Calver
- Department of Medicine, Physical Medicine and Rehabilitation, McMaster University, Hamilton, Canada
- College of Medicine, Department of Physical Medicine and Rehabilitation, University of Saskatchewan, Saskatoon, Canada
- College of Medicine, School of Rehabilitation Science, University of Saskatchewan, Saskatoon, Canada
| | - Alan Cudlip
- College of Medicine, Department of Physical Medicine and Rehabilitation, University of Saskatchewan, Saskatoon, Canada
| | - Clark R Dickerson
- Department of Kinesiology, Neuromechanics and Ergonomics Lab, Brock University, Ontario Canada
| | - Prosanta Mondal
- Faculty of Applied Health Sciences, Department of Kinesiology, Digital Industrial Ergonomics and Shoulder Evaluation Laboratory (DIESEL), University of Waterloo, Ontario, Canada
| | - Scotty Butcher
- College of Medicine, Department of Community Health and Epidemiology, University of Saskatchewan, Saskatoon, Canada
| | - Soo Y Kim
- College of Medicine, Department of Community Health and Epidemiology, University of Saskatchewan, Saskatoon, Canada
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Muscle fatigue response of rotator cuff muscles in different postures. Arch Orthop Trauma Surg 2022; 143:3191-3199. [PMID: 36305967 DOI: 10.1007/s00402-022-04650-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/08/2022] [Indexed: 02/09/2023]
Abstract
INTRODUCTION Muscle fatigue is a leading cause of rotator cuff (RC) pathologies. Scapular orientation affected by changes in the thoracic spine account for differences in body postures leading to altered RC muscle activation. This posture-related alteration in RC muscle activation and its fatigue response needs to be analyzed. MATERIALS AND METHODS This study included 50 healthy shoulders with no coexisting spine pathologies. Raw data were recorded using electromyography sensors for RC muscles during two isometric maneuvers of abduction and external rotation, performed at 30% maximum voluntary contraction at 30°, 45°, and 90° arm elevation in sitting and standing. The raw data were analyzed in DataLITE® software, and the mean power frequency (MPF) was extracted to analyze the fatigue response of RC muscles. The Wilcoxon signed-rank test and Kruskal-Wallis test with Bonferroni corrections analyzed fatigue differences between postures and various activities. P < 0.05 was considered significant for the results. RESULTS Supraspinatus muscle demonstrated significant fatigue at 90° of arm elevation in standing as compared to sitting (MPF -5.40: -5.41; P = 0.03) posture. Between the three elevation angles, all the RC muscles showed increased fatigue at 90° (MPF range -5.22 to -6.64). When compared between abduction and external rotation, only infraspinatus showed fatigue in external rotation (MPF range -5.42 to -6.08). Among all the three RC muscles, infraspinatus showed the maximum fatigue of MPF -6.64 when compared to supraspinatus -5.22 and teres minor -5.36. CONCLUSION The findings indicate that alterations in the body postures and different elevation angles affect the RC muscles' fatigue response.
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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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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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Tsuruike M, Ellenbecker TS. A comparison of teres minor and infraspinatus muscle activation in the prone position. JSES Int 2021; 6:116-122. [PMID: 35141685 PMCID: PMC8811400 DOI: 10.1016/j.jseint.2021.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background Methods Results Conclusion
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Affiliation(s)
- Masaaki Tsuruike
- Department of Kinesiology, College of Health and Human Sciences, San José State University, San Jose, CA, USA
- Corresponding author: Masaaki Tsuruike, PhD, ATC, Department of Kinesiology, San José State University, One Washington Square, San Jose, CA 95192-0054, USA.
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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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Lulic-Kuryllo T, Alenabi T, McDonald AC, Kim SY, Dickerson CR. Sub-regional activation of supraspinatus and infraspinatus muscles during activities of daily living is task dependent. J Electromyogr Kinesiol 2020; 54:102450. [PMID: 32711359 DOI: 10.1016/j.jelekin.2020.102450] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 07/10/2020] [Accepted: 07/11/2020] [Indexed: 11/18/2022] Open
Abstract
The supraspinatus and infraspinatus muscles each have multiple sub-regions that may activate differentially in activities of daily living. Awareness of these differential demands critically informs rehabilitation of rotator cuff muscle following injury, particularly if centered on recovering and strengthening the rotator cuff to perform daily tasks. This study quantified muscle activation of supraspinatus and infraspinatus sub-regions during the performance of six activities of daily living. Twenty-three participants (mean: 22.6 ± 2.6 years) completed the following tasks: opening a jar, reaching at shoulder height, overhead reaching, pouring water from a pitcher, eating with a spoon, and combing hair. Indwelling electromyography was collected from the anterior and posterior supraspinatus and superior, middle, and inferior infraspinatus. Tasks requiring high arm elevations (e.g. reaching at shoulder and overhead height) activated anterior supraspinatus between 21 and 28% MVC. The posterior supraspinatus consistently activated between 10 and 30% MVC across all tasks. All sub-regions of infraspinatus activated highly (between 18 and 25% MVC) in tasks requiring high arm elevations in flexion. These findings may be leveraged to define effective measures to increase rotator cuff function in daily tasks.
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Affiliation(s)
- Tea Lulic-Kuryllo
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada
| | - Talia Alenabi
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada
| | - Alison C McDonald
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada
| | - Soo Y Kim
- University of Saskatchewan, College of Medicine, School of Rehabilitation Science, Saskatoon, Saskatchewan, Canada
| | - Clark R Dickerson
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada.
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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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Development of a short and effective shoulder external rotation strength program in handball: A delphi study. Phys Ther Sport 2020; 44:92-98. [PMID: 32497989 DOI: 10.1016/j.ptsp.2020.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 05/11/2020] [Accepted: 05/11/2020] [Indexed: 11/23/2022]
Abstract
BACKGROUND Weakness of the shoulder external rotators (ER) is one of the main risk factors for shoulder pain in handball. Short, effective shoulder ER strength programs the players will adhere to are lacking. OBJECTIVES to develop a short and effective shoulder ER strength program, handball players will adhere to. METHODS We conducted a modified Delphi study, including experts in the field of shoulder, strength training and handball. In the first round, the experts were asked to rate eight pre-defined shoulder ER exercises on efficacy and adherence and to suggest other preferred exercises. In round two, they were asked to rate the new exercises from round one. In round three, they received a statistical summary of the panels scores, their own score and a summary of the suggestions. Based on the feedback, the experts were asked to revise their response. RESULTS Sixteen experts completed three rounds with 100% response rate. Twenty-eight exercises were rated. We reached consensus for both efficacy and adherence for two exercises, ER in 90° abduction in a bent-over squat position and ER in 90° abduction combined with horizontal abduction and trunk rotation in a push-up position. CONCLUSION We reached consensus for both efficacy and adherence for two exercises.
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Cudlip AC, Kim SY, Dickerson CR. The ability of surface electromyography to represent supraspinatus anterior and posterior partition activity depends on elevation angle, hand load and plane of elevation. J Biomech 2020; 99:109526. [PMID: 31780125 DOI: 10.1016/j.jbiomech.2019.109526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 11/11/2019] [Accepted: 11/14/2019] [Indexed: 10/25/2022]
Abstract
This study examined relationships between electromyography recorded from indwelling electrodes of the anterior and posterior supraspinatus and a surface supraspinatus electrode. Twenty male and twenty female participants completed full range humeral elevations in three planes of elevation (0/40/90°) and three hand loads (unloaded/20%/40% of maximal elevation strength). EMG activation was combined with motion capture to determine activation at instantaneous activation angles, and linear regressions of anterior and posterior indwelling electrodes relative to the surface electrode determined relationships between these signals. Regressions between surface and indwelling signals were affected by plane of elevation, elevation angle, load intensity and participant sex, but no interactions existed. Surface signals underestimated activation at low elevation angles for both regions, and up to 45% in the anterior supraspinatus (p < 0.01), then overestimated activation at higher elevation angles. Surface EMG underestimated indwelling signals by up to 15% in unloaded conditions, while overestimating the posterior region by up to 17% in the 40% load condition (p < 0.01). Sex effects showed increased overestimation by surface signals in the posterior region in males by 21% (p < 0.01). Better agreement existed for the anterior region than the posterior region across postures, but postural relationships should be considered when choosing electrodes for this muscle.
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Affiliation(s)
- Alan C Cudlip
- Department of Kinesiology, University of Waterloo, Waterloo, Canada
| | - Soo Y Kim
- School of Rehabilitation Science, University of Saskatchewan, Saskatoon, Canada.
| | - Clark R Dickerson
- Department of Kinesiology, University of Waterloo, Waterloo, Canada.
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Verification of intramuscular electromyography electrode placement for neuromuscular partitions of infraspinatus. J Electromyogr Kinesiol 2019; 49:102354. [DOI: 10.1016/j.jelekin.2019.102354] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/28/2019] [Accepted: 09/07/2019] [Indexed: 12/13/2022] Open
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Calver R, Alenabi T, Cudlip A, Dickerson CR, Mondal P, Kim SY. Regional activation of supraspinatus and infraspinatus sub-regions during dynamic tasks performed with free weights. J Electromyogr Kinesiol 2019; 62:102308. [PMID: 31109772 DOI: 10.1016/j.jelekin.2019.05.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 05/02/2019] [Accepted: 05/10/2019] [Indexed: 11/18/2022] Open
Abstract
Growing evidence supports the existence of distinct anatomical sub-regions within supraspinatus and infraspinatus, but only recently has attention turned to exploring their potential functional differences. Using indwelling fine-wire electromyography, muscle activity was investigated from these sub-regions in 15 participants (mean 34 yr, 170 cm, 71.9 kg) during dynamic external rotation (ER), abduction, flexion, and scaption tasks with and without free weights corresponding to 50% and 75% of the participant's five repetition maximum. Electromyography data were normalized to isometric and isokinetic maximal voluntary contractions and activation ratios for each sub-region compared. Differences in mean regional activation ratios for supraspinatus and infraspinatus varied by arm posture, but were not influenced by load. Relative activation of posterior supraspinatus was greater during an ER task performed in side lying compared to an ER task performed with 90° of humeral elevation in seated and prone postures. Relative activation of superior infraspinatus was greater during an ER task in prone and side lying postures compared to flexion and scaption. Similar results were found when comparing regional muscle activation ratios for infraspinatus between tasks regardless of normalization method employed. These findings may impact exercise selection in the non-operative management of rotator cuff tears.
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Affiliation(s)
- Ronelle Calver
- McMaster University, Department of Medicine, Division of Physical Medicine and Rehabilitation, Hamilton, Ontario, Canada
| | - Talia Alenabi
- University of Waterloo, Faculty of Applied Health Sciences, Department of Kinesiology, Digital Industrial Ergonomics and Shoulder Evaluation Laboratory (DIESEL), Waterloo, Ontario, Canada
| | - Alan Cudlip
- University of Waterloo, Faculty of Applied Health Sciences, Department of Kinesiology, Digital Industrial Ergonomics and Shoulder Evaluation Laboratory (DIESEL), Waterloo, Ontario, Canada
| | - Clark R Dickerson
- University of Waterloo, Faculty of Applied Health Sciences, Department of Kinesiology, Digital Industrial Ergonomics and Shoulder Evaluation Laboratory (DIESEL), Waterloo, Ontario, Canada
| | - Prosanta Mondal
- University of Saskatchewan, College of Medicine, Department of Community Health and Epidemiology, Saskatoon, Saskatchewan, Canada
| | - Soo Y Kim
- University of Saskatchewan, College of Medicine, School of Rehabilitation Science, Saskatoon, Saskatchewan, Canada.
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