Assessment of a Passive Lumbar Exoskeleton in Material Manual Handling Tasks under Laboratory Conditions.

Manual material handling tasks in industry cause work-related musculoskeletal disorders. Exoskeletons are being introduced to reduce the risk of musculoskeletal injuries. This study investigated the effect of using a passive lumbar exoskeleton in terms of moderate ergonomic risk. Eight participants were monitored by electromyogram (EMG) and motion capture (MoCap) while performing tasks with and without the lumbar exoskeleton. The results showed a significant reduction in the root mean square (VRMS) for all muscles tracked: erector spinae (8%), semitendinosus (14%), gluteus (5%), and quadriceps (10.2%). The classic fatigue parameters showed a significant reduction in the case of the semitendinosus: 1.7% zero-crossing rate, 0.9% mean frequency, and 1.12% median frequency. In addition, the logarithm of the normalized Dimitrov's index showed reductions of 11.5, 8, and 14% in erector spinae, semitendinosus, and gluteus, respectively. The calculation of range of motion in the relevant joints demonstrated significant differences, but in almost all cases, the differences were smaller than 10%. The findings of the study indicate that the passive exoskeleton reduces muscle activity and introduces some changes of strategies for motion. Thus, EMG and MoCap appear to be appropriate measurements for designing an exoskeleton assessment procedure.

Evaluación comparativa, mediante ensayos biomecánicos, de dispositivos de ostomía de dos piezas / Comparative evaluation through biomechanical tests of two-piece ostomy systems

OBJETIVO: comparar las propiedades mecánicas de los dispositivos de ostomía de dos piezas más empleados en España (Coloplast -o Fabricante I- y Fabricante II), mediante la realización de ensayos mecánicos. MÉTODO: los ensayos se realizaron en el Instituto de Biomecánica de Valencia (IBV), empleándose una máquina universal de ensayos MTS INSIGHT/468, con unas condiciones ambientales controladas de temperatura (22-24 ºC) y de humedad (39-41%). El tamaño de la muestra para cada uno de los ensayos fue de 10 unidades para cada tipo de sistema. Se llevaron a cabo tres pruebas: 1) Ensayo de resistencia a la degradación del adhesivo en solución salina; 2) Ensayo de resistencia al estallido del canal de vaciado de las bolsas abiertas; 3) Ensayo de resistencia a la separación entre el disco y la bolsa. RESULTADOS: en el ensayo de resistencia a la degradación del adhesivo en solución salina, los dos adhesivos, sometidos a periodos de degradación de 6 y 12 horas en solución salina a 37 ºC, presentaron diferencias significativas a favor del Fabricante I (Coloplast) para los dos periodos. En el ensayo de resistencia al estallido del canal de vaciado de las bolsas abiertas, con las bolsas llenas de agua, cerradas y pegadas sobre una plancha lisa, después de aplicar cargas de compresión hasta el estallido del canal, los dos sistemas no mostraron diferencias significativas. En el ensayo de resistencia a la separación entre el disco y la bolsa, ensamblada cada bolsa a su disco correspondiente y aplicadas cargas de tracción hasta la separación, también hubo diferencias significativas a favor del Fabricante I (Coloplast). CONCLUSIÓN: se puede afirmar que ambos sistemas son seguros, pero el sistema Coloplast presenta mayor durabilidad ante la degradación por el efluente y mayor coeficiente de seguridad frente a la separación entre la bolsa y el disco

OBJECTIVE: to compare the mechanical characteristics of the two-piece ostomy systems most widely used in Spain: (Coloplast or Manufacturer I and Manufacturer II), through mechanical tests. METHOD: tests were conducted in the Instituto de Biomecánica de Valencia (IBV), using a MTS INSIGHT/468 universal test machine, under environmental conditions of controlled temperature (22-24 ºC) and humidity (39-41%). The sample size for each test was 10 units per each type of system. Three tests were conducted: 1) Resistance test to degradation of the adhesive in saline solution; 2) Resistance test to burst of the outlet in open pouches; 3) Resistance test for the separation between the disc and the pouch. RESULTS: in the test of resistance to degradation of the adhesive in saline solution, both adhesives were submitted to 6 and 12-hour degradation periods in saline solution at 37 ºC, and significant differences were presented in favour of Manufacturer 1 (Coloplast) for both time periods. In the resistance test for the burst of the outlet in open pouches, the pouches were filled with water, closed and stuck on a flat plate; after applying compression charges until the outlet burst, both systems did not show any significant differences. In the resistance test for the separation between disc and pouch, each pouch was assembled with its disc, and traction charges were applied until their separation; there were significant differences in favour of Manufacturer I (Coloplast). CONCLUSION: it can be stated that both systems are safe, but the Coloplast system shows higher durability in terms of degradation by effluent, and a higher safety coefficient regarding the separation between pouch and disc

Evaluación comparativa mediante ensayos biomecánicos de anillos moldeables de ostomía / Comparative assessment through biomechanical trials between moldable rings for ostomy

OBJETIVO: determinar la resistencia a la degradación en solución salina de diversos anillos moldeables para ostomía, así como comprobar si existen diferencias estadísticamente significativas entre la resistencia a la degradación de los anillos moldeables de Coloplast (Col-2 y Col-4,2) con respecto a dos anillos moldeables comerciales de otros fabricantes (Fab1 y Fab2). MÉTODOS: el material objeto de ensayo consiste en cuatro modelos de anillos moldeables: Col-2 de 2 mm de espesor, Col-4,2 de 4,2 mm de espesor, Fab1 y Fab2 de espesor 4 mm. El tamaño de la muestra de ensayo fue de 10 unidades por tipo de sistema. Los ensayos fueron realizados en el laboratorio de ensayos del Instituto de Biomecánica de Valencia, utilizando una máquina universal de ensayos INSTRON8874/511, con unas condiciones ambientales de temperatura (23 ºC) y de humedad (56%). RESULTADOS: el análisis estadístico de los resultados revela diferencias estadísticamente significativas (p< 0,001) entre las muestras pertenecientes a Coloplast (Col-2= 1,84 N y Col-4,2 = 1,97 N) con las muestras de los fabricantes 1 y 2 (Fab1= 0,90 N y Fab2= 0,92 N). No se observan diferencias estadísticamente significativas entre las dos muestras de Coloplast (p= 0,706) ni entre las dos muestras de los otros dos fabricantes (p= 0,917). CONCLUSIÓN: las dos muestras de Coloplast presentan valores de fuerza de penetración significativamente mayores (dos veces superiores) que las muestras de los otros dos fabricantes y, por tanto, una mayor resistencia a la degradación a las seis horas de estar sumergida en un suero salino. Sin embargo, no se observan diferencias estadísticamente significativas en la resistencia a la degradación entre las dos muestras de Coloplast a pesar de ser anillos de diferente grosor. Este efecto se debe a que las mediciones se han realizado con penetraciones de 1 mm

OBJECTIVE: to determine the resistance to degradation in saline solution for different moldable rings for ostomy, as well to confirm if there are any statistically differences between the resistance to degradation in Coloplast moldable rings (Col-2 and Col-4.2) vs. two moldable rings marketed by other manufacturers (Fab1 and Fab2). METHODS: the material object of the trial consisted in four models of moldable rings: Col-2 with 2 mm thickness, Col-4.2 with 4.2 mm thickness, and Fab1 & Fab2 4 mm thickness. The trial sample size was 10 units per type of system. The trials were conducted at the testing laboratory of the Biomechanical Institute, Valencia, using a universal testing machine INSTRON8874/511, under environmental conditions of temperature (23 ºC) and humidity (56%). RESULTS: the statistical analysis of results revealed statistically significant differences (p< 0.001) between the Coloplast samples (Col-2= 1.84 N and Col-4.2 = 1.97 N) and the samples from manufacturers 1 and 2 (Fab1= 0.90 N and Fab2= 0.92 N). No statistically significant differences were observed between the two Coloplast samples (p= 0.706) or between the two samples from the other two manufacturers (p= 0.917). CONCLUSION: the two Coloplast samples presented significantly higher penetration strength values (twice higher) than the samples from the other two manufacturers; and therefore, higher resistance to degradation at six hours of being immersed in saline. However, no statistically significant differences were observed in terms of resistance to degradation between both Coloplast samples, regardless of the different thickness of the rings. This effect was due to measurements being conducted with 1mm penetrations