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Applied Ergonomics Jun 2024Many physically straining occupations involve lifting movements over the full-vertical range of motion, which over time may lead to the development of musculoskeletal...
Many physically straining occupations involve lifting movements over the full-vertical range of motion, which over time may lead to the development of musculoskeletal injuries. To address this, occupational exoskeletons can be designed to provide meaningful support to the back and shoulders during lifting movements. This paper introduces the main functional design features of the OmniSuit, a novel passive occupational exoskeleton. We present the technical and biomechanical considerations for the expected support level, as well as an evaluation of the physiological benefit and usability of the exoskeleton in a sample of 31 healthy volunteers performing physically demanding tasks in a laboratory setting. The OmniSuit exoskeleton significantly reduced Deltoid, Trapezius and Erector Spinae muscle activity between 4.1%MVC and 15.7%MVC when lifting a 2.5kg weight above shoulder level (p<0.001), corresponding to a reduction of up to 49.1% compared to without exoskeleton. A position-dependent reduction of Erector Spinae muscle activity was observed (p<0.001), with reductions ranging between 4.6%MVC and 14.0%MVC during leaning and squatting, corresponding to a reduction up to 41.5% compared to without exoskeleton. The measured muscular support and the predicted support torque based on the biomechanical model were found to show a similar profile for those phases of the movement which are most straining to the shoulder and back muscles. Participants reported experiencing good device usability and minimal discomfort (<1/10) in the shoulder and back during task execution with exoskeleton support. These first results validate that the considered biomechanical model helped design an ergonomic and efficient exoskeleton, and confirm the potential of such wearable assistive devices to provide support over multiple joints during physically demanding tasks.
PubMed: 38876001
DOI: 10.1016/j.apergo.2024.104332 -
Physiology & Behavior Jun 2024Muscle testing is an integral component in assessing musculoskeletal function and tailoring rehabilitation efforts. This study aimed i. to identify an objective... (Review)
Review
Muscle testing is an integral component in assessing musculoskeletal function and tailoring rehabilitation efforts. This study aimed i. to identify an objective evaluation system sensitive to analyze changes in different muscular conditions in different neuromuscular tests across a spectrum of professional experience levels; and ii. to analyze differences in objective parameters and clinical judgment between participants of different levels of expertise in different muscular conditions in different neuromuscular tests. Participants included 60 subjects with Level I to III expertise who performed blinded neuromuscular tests on the middle deltoid and rectus femoris muscles of 40 volunteer subjects. The methodology centered on standardizing test protocols to minimize variability, employing EMG to quantify muscle activity, thermography to capture thermographic muscular response, and digital dynamometry to measure muscular resistance. The findings revealed that while traditional methods like thermography and electromyography provide valuable insights, digital dynamometry stands out for its sensitivity in detecting muscle condition changes in neuromuscular test. Moreover, the data underscored the pivotal role of advanced training and expertise in enhancing the precision and accuracy of neuromuscular diagnostics, since there were significant differences in objective parameters and clinical judgment between participants of different levels of expertise in the different muscular conditions in Middle deltoid and Rectus femoris neuromuscular tests analyzed, presenting higher expertise participant clinical judgment like objective validated instrument.
PubMed: 38851442
DOI: 10.1016/j.physbeh.2024.114602 -
Journal of Orthopaedic Surgery and... Jun 2024Arthroscopic tuberoplasty is an optional technique for managing irreparable rotator cuff tears. However, there is a lack of studies investigating the resistance force...
BACKGROUND
Arthroscopic tuberoplasty is an optional technique for managing irreparable rotator cuff tears. However, there is a lack of studies investigating the resistance force during shoulder abduction in cases of irreparable rotator cuff tears and tuberoplasty.
HYPOTHESES
In shoulders with irreparable rotator cuff tears, impingement between the greater tuberosity (GT) and acromion increases the resistance force during dynamic shoulder abduction. Tuberoplasty is hypothesized to reduce this resistance force by mitigating impingement.
STUDY DESIGN
Controlled laboratory study.
METHODS
Eight cadaveric shoulders, with a mean age of 67.75 years (range, 63-72 years), were utilized. The testing sequence included intact rotator cuff condition, irreparable rotator cuff tears (IRCTs), burnishing tuberoplasty, and prosthesis tuberoplasty. Burnishing tuberoplasty refers to the process wherein osteophytes on the GT are removed using a bur, and the GT is subsequently trimmed to create a rounded surface that maintains continuity with the humeral head. Deltoid forces and actuator distances were recorded. The relationship between deltoid forces and actuator distance was graphically represented in an ascending curve. Data were collected at five points within each motion cycle, corresponding to actuator distances of 20 mm, 30 mm, 40 mm, 50 mm, and 60 mm.
RESULTS
In the intact rotator cuff condition, resistance forces at the five points were 34.25 ± 7.73 N, 53.75 ± 7.44 N, 82.50 ± 14.88 N, 136.25 ± 30.21 N, and 203.75 ± 30.68 N. In the IRCT testing cycle, resistance forces were 46.13 ± 7.72 N, 63.75 ± 10.61 N, 101.25 ± 9.91 N, 152.5 ± 21.21 N, and 231.25 ± 40.16 N. Burnishing tuberoplasty resulted in resistance forces of 32.25 ± 3.54 N, 51.25 ± 3.54 N, 75.00 ± 10.69 N, 115.00 ± 10.69 N, and 183.75 ± 25.04 N. Prosthesis tuberoplasty showed resistance forces of 29.88 ± 1.55 N, 49.88 ± 1.36 N, 73.75 ± 7.44 N, 112.50 ± 7.07 N, and 182.50 ± 19.09 N. Both forms of tuberoplasty significantly reduced resistance force compared to IRCTs. Prosthesis tuberoplasty further decreased resistance force due to a smooth surface, although the difference was not significant compared to burnishing tuberoplasty.
CONCLUSION
Tuberoplasty effectively reduces resistance force during dynamic shoulder abduction in irreparable rotator cuff tears. Prosthesis tuberoplasty does not offer a significant advantage over burnishing tuberoplasty in reducing resistance force.
CLINICAL RELEVANCE
Tuberoplasty has the potential to decrease impingement, subsequently reducing resistance force during dynamic shoulder abduction, which may be beneficial in addressing conditions like pseudoparalysis.
Topics: Humans; Rotator Cuff Injuries; Middle Aged; Aged; Biomechanical Phenomena; Cadaver; Male; Female; Shoulder Joint; Rotator Cuff; Arthroscopy; Range of Motion, Articular; Shoulder Impingement Syndrome
PubMed: 38849918
DOI: 10.1186/s13018-024-04740-w -
EJNMMI Reports Jun 2024During a phase 0 clinical trial of an investigational programmed cell death ligand-1 (PD-L1) PET tracer in patients with non-small cell lung cancer (NSCLC), three...
BACKGROUND
During a phase 0 clinical trial of an investigational programmed cell death ligand-1 (PD-L1) PET tracer in patients with non-small cell lung cancer (NSCLC), three patients received booster doses of COVID-19 vaccines before PD-L1 imaging.
METHODS
Five patients underwent whole-body PET/CT imaging with a novel PD-L1 tracer, constructed by attaching Zr to the anti PD-L1 antibody durvalumab. Intramuscular (deltoid) booster doses of mRNA BNT162b2 COVID-19 mRNA vaccine were coincidentally given to three patients in the month before PD-L1 tracer injection.
RESULTS
Two recently-vaccinated patients, in remission of NSCLC and receiving non-immunosuppressive cancer therapies (immunotherapy and tyrosine kinase inhibitor respectively), showed increasing PD-L1 tracer uptake in ipsilateral axillary lymph nodes. No asymmetric nodal uptake was seen in a third recently-vaccinated patient who was receiving immunosuppressive chemotherapy, or in two patients not recently-vaccinated.
CONCLUSION
Immune response to mRNA BNT162b2 vaccination may involve regulation by PD-L1 positive immune cells in local draining lymph nodes in immunocompetent patients.
TRIAL REGISTRATION
This trial was registered with the Australian New Zealand Clinical Trials Registry. Registration number ACTRN12621000171819. Date of Trial Registration 8/2/2021. Date of enrolment of 1st patient 11/4/2021. URL of trial registry record: https://www.australianclinicaltrials.gov.au/anzctr/trial/ACTRN12621000171819 .
PubMed: 38844699
DOI: 10.1186/s41824-024-00196-7 -
Journal of Sports Science & Medicine Jun 2024Arm-cycling is a versatile exercise modality with applications in both athletic enhancement and rehabilitation, yet the influence of forearm orientation remains...
Arm-cycling is a versatile exercise modality with applications in both athletic enhancement and rehabilitation, yet the influence of forearm orientation remains understudied. Thus, this study aimed to investigate the impact of forearm position on upper-body arm-cycling Wingate tests. Fourteen adult males (27.3 ± 5.8 years) underwent bilateral assessments of handgrip strength in standing and seated positions, followed by pronated and supinated forward arm-cycling Wingate tests. Electromyography (EMG) was recorded from five upper-extremity muscles, including anterior deltoid, triceps brachii lateral head, biceps brachii, latissimus dorsi, and brachioradialis. Simultaneously, bilateral normal and propulsion forces were measured at the pedal-crank interface. Rate of perceived exertion (RPE), power output, and fatigue index were recorded post-test. The results showed that a pronated forearm position provided significantly (p < 0.05) higher normal and propulsion forces and triceps brachii muscle activation patterns during arm-cycling. No significant difference in RPE was observed between forearm positions (p = 0.17). A positive correlation was found between seated handgrip strength and peak power output during the Wingate test while pronated (dominant: p = 0.01, r = 0.55; non-dominant: p = 0.03, r = 0.49) and supinated (dominant: p = 0.03, r = 0.51; don-dominant: p = 0.04, r = 0.47). Fatigue changed the force and EMG profile during the Wingate test. In conclusion, this study enhances our understanding of forearm position's impact on upper-body Wingate tests. These findings have implications for optimizing training and performance strategies in individuals using arm-cycling for athletic enhancement and rehabilitation.
Topics: Humans; Male; Electromyography; Forearm; Hand Strength; Adult; Muscle, Skeletal; Young Adult; Biomechanical Phenomena; Pronation; Exercise Test; Supination; Muscle Fatigue; Physical Exertion; Arm; Upper Extremity
PubMed: 38841629
DOI: 10.52082/jssm.2024.396 -
Frontiers in Sports and Active Living 2024Unstable surfaces are commonly utilized to enhance the flexibility of the musculoskeletal system for achieving training or rehabilitation goals. However, their effects...
Electromyography of shoulder muscles in individuals without scapular dyskinesis during closed kinetic chain exercises on stable and unstable surfaces: a systematic review and meta-analysis.
INTRODUCTION
Unstable surfaces are commonly utilized to enhance the flexibility of the musculoskeletal system for achieving training or rehabilitation goals. However, their effects on shoulder muscle activation during various push-up (PU) exercises have not been thoroughly investigated. Therefore, the purpose of this study was to synthesize electromyography (EMG) data of shoulder muscles in individuals without scapular dyskinesis performing different PU exercises on both stable and unstable surfaces.
METHODS
A systematic online search was conducted in electronic databases, including Web of Science, PubMed, Scopus, and Google Scholar, up to January 16, 2024, using predefined sets of keywords. Out of the 1,971 titles and abstracts screened, 80 articles were reviewed in detail by two independent researchers to check the eligibility, of which 28 eligible studies were ultimately included. Following assessment of the quality and risk of bias, the studies were categorized based on exercises and muscle groups, and a meta-analysis using a random-effects model was performed to estimate the overall effect size.
RESULTS
The use of unstable surfaces led to a decrease in anterior deltoid activity during PU [ = 0.032; = 91.34%; SMD = -0.630 (95% CI -1.205, -0.055)], an increase in pectoralis major activity during PU [ = 0.006; = 63.72%; SMD = 0.282 (95% CI 0.079, 0.484)], as well as during knee PU [ = 0.018; = 32.29%; SMD = 0.309 (95% CI 0.052, 0.565)], and an increase in triceps brachii activity during PU [ = 0.000; = 85.05%; SMD = 0.813 (95% CI 0.457, 1.168)], knee PU [ = 0.000; = 0.00%; SMD = 0.589 (95% CI 0.288, 0.891)], as well as during push-up plus [ = 0.006; = 13.16%; SMD = 0.563 (95% CI 0.161, 0.965)]. However, the use of unstable surfaces did not show a significant effect on the EMG activity of the pectoralis major during push-up plus [ = 0.312; = 22.82%; SMD = 0.207 (95% CI -0.194, 0.609)].
CONCLUSIONS
Unstable surfaces can modulate muscle activity in different PU exercises, while the effects on the targeted muscles depend on the type of exercise. The findings of this review provide a framework based on the level of activity of each shoulder muscle during different PU exercises, which can help coaches, trainers, and sports therapists select the most suitable type of PU for designing training or rehabilitation programs. Particularly, the most suitable exercise for increasing anterior deltoid activity is PU on a stable surface. To concurrently increase activity of the pectoralis major and triceps brachii, adding unstable surfaces under hands during knee PU and standard PU is recommended.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO, identifier CRD42021268465.
PubMed: 38840951
DOI: 10.3389/fspor.2024.1385693 -
Cureus Apr 2024Introduction Acromioplasty is a widely performed procedure for various rotator cuff pathologies with good outcomes and high patient satisfaction. However, few studies...
Introduction Acromioplasty is a widely performed procedure for various rotator cuff pathologies with good outcomes and high patient satisfaction. However, few studies have focused on its potential complications. Previous cadaveric studies have demonstrated that a considerable portion of the deltoid muscle is detached from its acromial origin following arthroscopic acromioplasty, but the clinical relevance of this muscle detachment has not been investigated. The goal of our research was to examine the influence of arthroscopic acromioplasty on abduction strength and to assess whether acromial anatomy plays a role in any potential effect. Methods From a preliminary sample of 87 individuals who were diagnosed with isolated impingement syndrome and underwent arthroscopic acromioplasty, 74 patients who met the inclusion criteria were ultimately included in the study. The patients were divided into two groups according to their acromion morphology: Bigliani type 2 (33 patients) and type 3 (41 patients). The isometric abduction strength of the two groups was measured by a handheld dynamometer (Isobex®; Cursor AG, Berne, Switzerland) at different abduction angles preoperatively and at the first, third, and sixth months following surgery and was statistically compared. Results Both groups showed reduced abduction strength postoperatively; however, the strength of abduction in the Bigliani type 3 group returned to near preoperative values in the third month. Although increased mean abduction strength was recorded at 30° abduction in the sixth month, this difference was not statistically significant (p=0.78). In the Bigliani type 2 group, compared with those in the sixth-month group, the preoperative abduction strength decreased from 8.32 kg to 6.0 kg (p = 0.047), 6.57 kg to 5.15 (p = 0.025), and 6.1 kg to 4.56 kg (p = 0.006) at 30, 60, and 90° abduction, respectively. Conclusions Arthroscopic acromioplasty decreased isometric abduction strength in patients with a Bigliani type 2 acromion. Patients should be counseled about this loss, which might be especially important for professional athletes and heavy manual workers.
PubMed: 38826604
DOI: 10.7759/cureus.59426 -
Shoulder & Elbow Jul 2024An intramuscular abscess of the subscapularis is a rare phenomenon but important pathology for surgeons to be aware of because clinical deterioration can be rapid and... (Review)
Review
BACKGROUND
An intramuscular abscess of the subscapularis is a rare phenomenon but important pathology for surgeons to be aware of because clinical deterioration can be rapid and diagnosis difficult. The presentation often mimics other common shoulder pathologies with subacute shoulder pain and stiffness. Early diagnosis, antibiotics and surgical drainage are critical to reduce the spread and joint destruction.
METHODS
A search of PubMed and Google Scholar databases identified cases of subscapular intramuscular abscess. Data collected about each case included patient demographics, presentation, pathology, surgical treatment and outcome. The authors report one additional subscapular abscess case.
RESULTS
Data from 17 cases of subscapular abscess were found, 16 in the literature and one case described by the authors. Sixteen of 17 cases (94.1%) presented with shoulder pain and reduced range of motion worsening over a mean of 6.7 days prior to presentation. Surgical approaches utilised included a posterior inferomedial approach, deltoid-pectoral approach and one posterior inferolateral approach.
DISCUSSION AND CONCLUSIONS
From the limited data available regarding subscapular intramuscular abscess, the authors make the following recommendations: (1) Empirical antibiotics covering +/- methicillin-resistant , (2) drainage is indicated in all cases; and (3) tendon-sparing approaches can access an abscess in most locations within the subscapular space.
PubMed: 38818095
DOI: 10.1177/17585732231165194 -
Clinical Orthopaedics and Related... Jun 2024
Erratum to: Compensatory Movement Patterns Are Based on Abnormal Activity of the Biceps Brachii and Posterior Deltoid Muscles in Patients with Symptomatic Rotator Cuff Tears.
Topics: Humans; Rotator Cuff Injuries; Deltoid Muscle; Rotator Cuff; Muscle, Skeletal; Range of Motion, Articular; Shoulder Joint; Adaptation, Physiological
PubMed: 38809677
DOI: 10.1097/CORR.0000000000003112 -
Frontiers in Bioengineering and... 2024Osteoarthritis (OA) and rotator cuff tear (RCT) pathologies have distinct scapular morphologies that impact disease progression. Previous studies examined the...
Effect of patient-specific scapular morphology on the glenohumeral joint force and shoulder muscle force equilibrium: a study of rotator cuff tear and osteoarthritis patients.
Osteoarthritis (OA) and rotator cuff tear (RCT) pathologies have distinct scapular morphologies that impact disease progression. Previous studies examined the correlation between scapular morphology and glenohumeral joint biomechanics through critical shoulder angle (CSA) variations. In abduction, higher CSAs, common in RCT patients, increase vertical shear force and rotator cuff activation, while lower CSAs, common in OA patients, are associated with higher compressive force. However, the impact of the complete patient-specific scapular morphology remains unexplored due to challenges in establishing personalized models. CT data of 48 OA patients and 55 RCT patients were collected. An automated pipeline customized the AnyBody™ model with patient-specific scapular morphology and glenohumeral joint geometry. Biomechanical simulations calculated glenohumeral joint forces and instability ratios (shear-to-compressive forces). Moment arms and torques of rotator cuff and deltoid muscles were analyzed for each patient-specific geometry. This study confirms the increased instability ratio on the glenohumeral joint in RCT patients during abduction (mean maximum is 32.80% higher than that in OA), while OA patients exhibit a higher vertical instability ratio in flexion (mean maximum is 24.53% higher than that in RCT) due to the increased inferior vertical shear force. This study further shows lower total joint force in OA patients than that in RCT patients (mean maximum total force for the RCT group is 11.86% greater than that for the OA group), attributed to mechanically advantageous muscle moment arms. The findings highlight the significant impact of the glenohumeral joint center positioning on muscle moment arms and the total force generated. We propose that the RCT pathomechanism is related to force magnitude, while the OA pathomechanism is associated with the shear-to-compressive loading ratio. Overall, this research contributes to the understanding of the impact of the complete 3D scapular morphology of the individual on shoulder biomechanics.
PubMed: 38807649
DOI: 10.3389/fbioe.2024.1355723