Ciències Bàsiques

Electromyographic Activity of the Shoulder Muscles During Arm Elevation in Asymptomatic Subjects—A Cross-Sectional Study

2026-04-22T02:00:40Z

Electromyographic Activity of the Shoulder Muscles During Arm Elevation in Asymptomatic Subjects—A Cross-Sectional Study Barra-López, Martín Eusebio; López-de-Celis, Carlos; Garcia Ribell, Erik; Rodríguez-Rodríguez, Sergi; Malo Urriés, Miguel; Rodríguez-Sanz, Jacobo Background: Although several studies have compared muscle activity in ‘healthy’ and ‘unhealthy’ shoulders, studying ‘healthy’ shoulders alone could improve the understanding of shoulder biomechanics. Objective: This study aims to describe the electromyographic activity of several shoulder muscles during a full range of free active flexion, as well as during abduction and scaption movements, and to compare gender differences in subjects with no history of shoulder pain or pathology. Methods: A cross-sectional descriptive study was conducted with 34 subjects aged between 18 and 60 years of both genders. The activity of the anterior, middle, and posterior deltoid, serratus anterior, infraspinatus, latissimus dorsi, and teres major muscles was measured using surface electromyography. Root Mean Square (RMS) values were calculated as a percentage of Maximal Voluntary Isometric Contraction (MVIC). Results: Regardless of whether they are considered agonists or antagonists, these muscles were active, with no statistically significant differences (Mann–Whitney U test), during both the lifting and lowering phases of the studied movements. Statistically significant differences between movements were observed only in the deltoid (Kruskal–Wallis H test, p < 0.004), which was more active during abduction. Women showed statistically significant muscle activity increase compared with men in some movements, except in the infraspinatus muscle—for example, in the three parts of the deltoid during the lifting phase of scaption (ANCOVA, p = 0.002–0.024). Conclusions: In this sample, the shoulder muscles studied showed comparable activity, acting as agonists or antagonists during shoulder elevation. These findings are exploratory and may help inform future studies on muscle activation in healthy shoulders during more varied functional tasks.

Desarrollo y validación de un sistema de aprendizaje específico de técnicas mínimamente invasivas guiadas por ecografía en Cirugía Ortopédica y TraumatologíaDevelopment and validation of a specific learning system for minimally invasive ultrasound-guided techniques in Orthopedic Surgery and Traumatology

2026-04-15T02:01:59Z

Desarrollo y validación de un sistema de aprendizaje específico de técnicas mínimamente invasivas guiadas por ecografía en Cirugía Ortopédica y TraumatologíaDevelopment and validation of a specific learning system for minimally invasive ultrasound-guided techniques in Orthopedic Surgery and Traumatology Calvo Tapies, Jorge Rafael; Albareda, Jorge; Gomez-Vallejo, Jesús; Redondo Trasobares, Beatriz; Blanco-Rubio, Nieves; Ballesteros-Betancourt, José; Bueno-Gracia, Elena; Fanlo Mazas, Pablo; Ríos Asín, Izarbe; Pérez Rey, Jorge; Rodríguez-Sanz, Jacobo; Malo Urriés, Miguel Introducción: Las técnicas mínimamente invasivas guiadas por ecografía han demostrado un notable crecimiento en Cirugía Ortopédica y Traumatología. Sin embargo, su aprendizaje presenta una elevada complejidad, lo que ha impulsado el desarrollo de modelos de simulación específicos como herramienta docente. Objetivo: Evaluar la efectividad de un programa de entrenamiento mediante phantoms personalizados para la adquisición de habilidades en técnicas mínimamente invasivas guiadas por ecografía. Métodos: Estudio prospectivo comparativo con 20 médicos internos residentes, distribuidos en grupo intervención (n=10; formación con phantoms) y grupo control (n=10; formación habitual sin entrenamiento con phantom). Se evaluó la transferencia del aprendizaje en un modelo cadavérico, el desempeño técnico mediante rúbricas específicas y la autopercepción de competencia mediante cuestionarios. Resultados: El grupo intervención mostró una reducción significativa en el tiempo de ejecución (p<0,001) y en el número de intentos (p<0,001). Además, obtuvo mejores resultados en desempeño técnico y autopercep ción, destacando diferencias significativas en la satisfacción (p=0,002), el esfuerzo percibido (p=0,035) y la frustración (p<0,001). Conclusión: El entrenamiento con phantoms personalizados mejora el aprendizaje técnico y la percepción de competencia en técnicas mínimamente invasivas guiadas por ecografía, representando una herramienta eficaz y transferible para la formación en Cirugía Ortopédica y Traumatología.

Normative Data of Neuromuscular Function in Upper Limb and Its Correlation with Superficial Fascia and Body Mass Composition

2026-03-25T10:19:07Z

Normative Data of Neuromuscular Function in Upper Limb and Its Correlation with Superficial Fascia and Body Mass Composition Casasayas-Cos, Oriol; Labata-Lezaun, Noé; LLURDA ALMUZARA, LUIS; Ortiz Miguel, Sara; Smit, Johke; López-de-Celis, Carlos; Albert, Pérez-Bellmunt Background/Objectives: Neuromuscular functions (NMFs) encompass biomechanical and viscoelastic properties that are essential for coordinated movement and muscular control. While NMFs have been extensively investigated in the lower limb, normative data for the upper extremity remain limited, particularly regarding the interaction between neuromuscular properties, superficial fascia, and body composition. As body composition and fascial characteristics may influence neuromuscular behavior and the interpretation of mechanical measurements, this study aimed to establish reference values for upper limb NMF, analyze dominance-related differences, and investigate the relationship between superficial fascia thickness and body mass composition. Methods: A descriptive, non-experimental study was conducted involving 61 healthy adults (122 upper limbs). Assessments included body composition (bioimpedance), superficial fascia thickness (skinfolds), viscoelastic properties (MyotonPro), and isometric strength (handheld dynamometry). Standardized protocols were applied for all measurements. Comparisons were performed between sexes and between dominant and non-dominant limbs. Correlation analyses explored associations between NMF, adiposity, and fascia parameters. Results: Dominant limbs showed slightly greater strength; however, these differences were not statistically significant. Viscoelastic properties were largely symmetrical between limbs, with minimal dominance-related differences. Clear sex differences were observed: men demonstrated greater strength, lean mass, and increased stiffness, whereas women presented higher skinfold thickness and lower muscle tone. Weak correlations were identified between stiffness, relaxation, and strength, as well as between adiposity and superficial fascia thickness. Greater adipose thickness was associated with lower stiffness values in the triceps (rho= −0304; iC95% 0.041/0.528; p = 0.017). Conclusions: Upper limb neuromuscular properties exhibit high bilateral symmetry, with limb dominance influencing strength. Sex and body composition significantly modulate both viscoelastic and functional parameters. These findings provide normative reference values and highlight the relevance of considering body composition and fascial characteristics when assessing neuromuscular function in clinical and sports contexts.

Silkworm gut fibre-based biosensors for optical glucose detection

2026-03-25T11:50:13Z

Silkworm gut fibre-based biosensors for optical glucose detection Fitó Parera, Aina; Márquez, Augusto; Rodríguez-Núñez, Pablo; AZNAR CERVANTES, SALVADOR; Reguera, Ana Cristina; Perdigones Sánchez, Francisco Antonio; Aracil Fernández, Carmen; Rodriguez-Rodriguez, Rosalia; Dominguez Horna, Carlos; munoz berbel, xavier Silk is a re-emerging biomaterial with significant potential for optical waveguiding due to its high transparency in the visible spectrum and elevated refractive index. Naturally occurring silk filamentous structures, such as silkworm gut fibres (SGFs), resemble traditional optical fibres while offering advantages such as biocompatibility, flexibility, mechanical strength and biodegradability. In this study, SGFs from different Bombyx mori races were evaluated for their suitability in optical fibre-based biosensing applications. White SGFs were selected for their superior optical properties, including a broad transmission window in the visible spectrum, strong light confinement, and high guidance efficiency. However, pristine SGFs exhibited sensitivity to hydration/drying cycles, leading to transmission losses. To address this, an alginate cladding was applied, stabilizing the fibre while preserving biocompatibility and optical performance. The modified SGFs successfully quantified colorants in the surrounding medium and were further employed in biochemical sensing. Specifically, alginate-coated SGFs enabled glucose detection by monitoring the colorimetric response of a redox mediator oxidized through a bi- enzymatic reaction involving glucose oxidase and peroxidase. This system effectively distinguished glucose concentrations corresponding to healthy, hypoglycaemic, and hyperglycaemic (pre-diabetic and diabetic) conditions. Furthermore, direct glucose measurements in real blood samples were possible, as the alginate layer functioned as a size-exclusion filter, selectively retaining cellular components while allowing glucose to diffuse and react with immobilized enzymes and redox mediators. The use of silk and alginate, both recognised as biodegradable materials, suggests significant potential for the development of real-time, minimally invasive glucose monitoring systems for in vitro and in vivo analysis. This work was financially supported by the MICINN State Research Agency AEI (PID2021-127653NB-C21). Dr. Salvador Aznar acknowledges partial financial support from the European Commission ERDF/FEDER Operational Programme of Murcia (2021-2027), Project No. 50463 "Development of sustainable models of agricultural, livestock and aquaculture production" (Subproject: Innovation in the field of sericulture: New materials, biomaterials and extracts of biomedical interest).