An optimal procedure for stride length estimation using foot-mounted magneto-inertial measurement units

Stride length is often used to quantitatively evaluate human locomotion performance. Stride by stride estimation can be conveniently obtained from the signals recorded using miniaturized inertial sensors attached to the feet and appropriate algorithms for data fusion and integration. To reduce the detrimental drift effect, different algorithmic solutions can be implemented. However, the overall method accuracy is supposed to depend on the optimal selection of the parameters which are required to be set. This study aimed at evaluating the influence of the main parameters involved in well-established methods for stride length estimation. An optimization process was conducted to improve methods' performance and preferable values for the considered parameters according to different walking speed ranges are suggested. A parametric solution is also proposed to target the methods on specific subjects' gait characteristics. The stride length estimates were obtained from straight walking trials of five healthy volunteers and were compared with those obtained from a stereo-photogrammetric system. After parameters tuning, percentage errors for stride length were 1.9%, 2.5% and 2.6% for comfortable, slow, and fast walking conditions, respectively

On the Detection of High-Quality, High-Density Electromyograms During 80m Sprints: a Case Study

Surface electromyograms (EMGs) have been often used to study muscle function in locomotor activities. Typically, EMGs are sampled with a single pair of electrodes, providing information on the timing and degree of muscle excitation. Additional information may be obtained when sampling EMGs with multiple electrodes from the same, target muscles. Studies using high-density EMGs (HD-EMGs) in locomotor activities are limited to laboratory settings and low speed tasks, likely due to the technical shortcomings in the commercially available systems for high-density recordings. This issue is further aggravated when kinematics data are necessary for associating EMGs with events of interest during the movement cycle. By combining two systems, ad hoc developed for the on-field recording of kinematics data and HD-EMGs, here we present single-case results during extreme-speed locomotion-the 80 m sprint on an official, athletic track. Our aim was to verify whether descriptors of quality documented in the EMG literature during well-controlled, isometric contractions, apply to the HD-EMGs we detected and segmented with respect to the running cycles. From a single, elite sprinter, we were able to obtain HD-EMGs with negligible movement artifacts and with temporal profiles typically characterizing action potentials of single motor units. Our results would seem to advocate the possibility of using HD-EMG to study muscle function during highly dynamic contractions outside the laboratory settings

Running speed changes the distribution of excitation within the biceps femoris muscle in 80m sprints

Predictors and mitigators of strain injuries have been studied in sprint-related sports. While the rate of axial strain, and thus running speed, may determine the site of muscle failure, muscle excitation seemingly offers protection against failure. It seems therefore plausible to ask whether running at different speeds changes the distribution of excitation within muscles. Technical limitations undermine however the possibility of addressing this issue in high-speed, ecological conditions. Here we circumvent these limitations with a miniaturized, wireless, multi-channel amplifier, suited for collecting spatio-temporal data and high-density surface electromyograms (EMGs) during overground running. We segmented running cycles while 8 experienced sprinters ran at speeds close to (70% and 85%) and at (100%) their maximum, over an 80 m running track. Then we assessed the effect of running speed on the distribution of excitation within biceps femoris (BF) and gastrocnemius medialis (GM). Statistical parametric mapping (SPM) revealed a significant effect of running speed on the amplitude of EMGs for both muscles, during late swing and early stance. Paired SPM revealed greater EMG amplitude when comparing 100% with 70% running speed for BF and GM. Regional differences in excitation were observed only for BF however. As running speed increased from 70% to 100% of the maximum, a greater degree of excitation was observed at more proximal BF regions (from 2% to 10% of the thigh length) during late swing. We discuss how these results, in the context of the literature, support the protective role of pre-excitation against muscle failure, suggesting the site of BF muscle failure may depend on running speed

Evaluación de FAMACHA© en el control de nematodes gastrointestinales en cabras de San Luis (Argentina)

Dentro de las enfermedades que ocasionan un gran deterioro en la producción caprina, las parasitosis por los nematodes gastrointestinales tienen una importancia preponderante, especialmente las producidas por Haemonchus contortus, especie dominante en el centro de la Argentina y de mayor significación por las pérdidas que ocasiona. Con el objetivo de evaluar el sistema de control FAMACHA© (FAM) en la detección de anemia en cabras de San Luis (SL) (Argentina), se muestrearon 42 animales en un establecimiento de producción de cabritos ubicado en Villa Mercedes (SL). Durante los meses estivales se determinó la presencia o no de anemia mediante el color de la mucosa ocular según la escala de la carta de colores FAM con cinco grados, el hematocrito (Hem), la condición corporal (CC), el conteo de huevos (hpg) y las especies de nematodos presentes. Las observaciones se realizaron sobre dos grupos de 21 animales: el G1 sin desparasitar al comienzo del ensayo y el G2 desparasitado al comienzo de la estación estival (manejo del establecimiento) con Ricobendazol al 15% ajustada a dosis caprina. Los animales con los grados FAM 4 y 5 fueron desparasitados con la misma droga y dosis. Se estimó la correlación existente entre los grados de FAM, Hem y CC, como la sensibilidad (S), especificidad (E) y los valores predictivos positivo (VP+) y negativo (VP-), usando el Hem ≤19% para determinar anemia. Los coprocultivos demostraron un predominio de Haemonchus sp. superior al 64% promedio del período. Los grados de FAM 2 y 3 fueron los más numerosos y con hematocritos más altos que los de la bibliografía, mientras que los grados 4 y 5 se encontraron dentro de los parámetros de hematocritos anémicos. Los coeficientes de correlación (p a 99,2%) demostrando seguridad al diagnosticar a los verdaderos negativos. Por el contrario, el VP+ fue bajo al considerar positivos los valores 3, 4 y 5 seguramente debido al alto porcentaje de falsos positivos, pero mediano al considerar positivos los valores 4 y 5. Al final del estudio se observó la misma carga de hpg entre los grupos, a pesar de que G1 utilizó un 41% menos de antihelmíntico respecto a G2. El uso de FAMACHA© en caprinos constituye una herramienta de gran utilidad para el control de la haemoncosis, ya que permite detectar y desparasitar a los animales del rebaño que se manifiestan como más sensibles a los Haemonchus sp. (tratamientos selectivos).Among the diseases that cause a significant deterioration in goat production, gastrointestinal parasitic nematodes have a preponderant importance, especially those produced by Haemonchus contortus, dominant species in the center of Argentina and major significance for the losses it causes. In order to evaluate the control system FAMACHA© (FAM) in detecting anemia in goats from San Luis (Argentina), 42 animals were sampled in a breeding of goat kids located in Villa Mercedes (SL). During the summer months the presence or absence of anemia by the color of the ocular mucosa was determined according to the scale of the color chart FAM five degrees, hematocrit (Hem), body condition (BC), egg counts (epg) and nematode species present. The observations were performed on two groups of 21 animals: the G1 without deworming at the beginning of the trial and the G2 dewormed at the beginning of the summer season (routine treatment of field) with Ricobendazol adjusted to 15% goat’s dose. Animals with FAM grades 4 and 5 were dewormed with the same drug and dosage. The correlation between degrees of FAM, Hem and BC, such as sensitivity (S), specificity (Sp) and positive predictive values (PV +) and negative (PV -) using the Hem ≤19% was estimated to determine anemia. Stool cultures showed a prevalence higher than 64% on average of Haemonchus sp. in the study period. FAM grades 2 and 3 were the most numerous, and with higher hematocrit than those reported in the literature, while grades 4 and 5 were within the parameters of hematocrit considered anemic. The correlation coefficients (p 99.2%) demonstrating safety to diagnose true negatives. By contrast the VP + was low when considering positive the values 3, 4 and 5 probably due to the high percentage of false positives, but medium to consider positive values 4 and 5. At the end of the study the same burden of epg was observed between groups, although G1 used 41% less of anthelmintic compared to G2. FAMACHA© use in goats is a useful tool for controlling the haemoncosis, since it can detect and deworming herd animals that appear to be more sensitive to Haemonchus sp. (Selective treatments).EEA San LuisFil: Rossanigo, Carlos Esteban. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Luis; ArgentinaFil: Page, Walter Juan Percy. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Luis; Argentin

Phylogenetic analysis of ORF viruses from five contagious ecthyma outbreaks in Argentinian goats

Orf virus (ORFV) is the etiological agent of Contagious Ecthyma (CE) disease that mainly affects sheep, goats, wild ruminants, and humans with a worldwide distribution. To date, only two strains from Argentinian sheep have been characterized at the molecular level and there is little information on ORFV strains circulating in Argentina. Here we describe and analyze five outbreaks of CE in goats in three geographic regions of the country: Northwest, Center, and Southwest. The phylogenetic analysis based on four molecular markers of ORFV (orf011 partial sequence and orf020, orf109, and orf127 complete sequence genes) revealed that there are different strains circulating in Argentina and pointed out the importance of knowing the health status of animals traded between farms.Instituto de BiotecnologíaFil: Peralta, Andrea Veronica. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Robles, Carlos Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Grupo Salud Animal; ArgentinaFil: Micheloud, Juan Francisco. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta. Grupo de Trabajo de Patología, Epidemiología e Investigación Diagnóstica. Área de Sanidad Animal; ArgentinaFil: Rossanigo, Carlos Esteban. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Luis; ArgentinaFil: Martínez, Agustín. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Grupo Salud Animal; ArgentinaFil: Carosio, Agustin. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Luis; ArgentinaFil: Konig, Guido Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Phylogenetic Analysis of ORF Viruses From Five Contagious Ecthyma Outbreaks in Argentinian Goats

Orf virus (ORFV) is the etiological agent of Contagious Ecthyma (CE) disease that mainly affects sheep, goats, wild ruminants, and humans with a worldwide distribution. To date, only two strains from Argentinian sheep have been characterized at the molecular level and there is little information on ORFV strains circulating in Argentina. Here we describe and analyze five outbreaks of CE in goats in three geographic regions of the country: Northwest, Center, and Southwest. The phylogenetic analysis based on four molecular markers of ORFV (orf011 partial sequence and orf020, orf109, and orf127 complete sequence genes) revealed that there are different strains circulating in Argentina and pointed out the importance of knowing the health status of animals traded between farms

Field Validity and Feasibility of Four Techniques for the Detection of Trichuris in Simians: A Model for Monitoring Drug Efficacy in Public Health?

Worldwide, millions of people are infected with soil-transmitted helminths, particularly in developing countries. Efforts to control these infections involve periodic mass drug treatment in endemic areas. Since these large-scale interventions are likely to intensify, monitoring of drug efficacy has become a key issue in order to detect the emergence of resistance. At present, the drop in infection intensity is under examination for monitoring the drug efficacy. However, studies comparing detection techniques based on infection intensities are scarce. Moreover, little attention has been addressed to their feasibility and their ability to estimate drug efficacies. We have compared different techniques for the detection of whipworm (Trichuris) in simian stool samples based on prevalence, infection intensities, feasibility and ability to estimate the ‘true’ drug efficacy. We have found that techniques often fail to detect low infection intensities and that not all techniques are appropriate for estimating infection intensities. The time needed to obtain a test result varied from 3.9 to 17.7 min/sample. Finally, accurate estimates of drug efficacy were only obtained in high pre-drug administration infection intensities. To conclude, along with accurate estimates of infection intensities, feasibility is a considerable criterion for the detection techniques used in drug efficacy monitoring programs

Brucelosis caprina en la Argentina

La brucelosis caprina es una enfermedad infecto-contagiosa de distribución mundial, de curso crónico, causada por alguno de los tres biovares de Brucella melitensis, con un alto impacto en la producción caprina, debido a la producción de abortos tardíos en cabras y orquitis y artritis en los machos cabríos. Además, constituye una importante zoonosis, ya que el humano se contagia la enfermedad por el estrecho contacto que existe entre la familia y los animales en este tipo de cría y por la ingestión de leche cruda y/o sus derivados. A diferencia de los países mediterráneos, donde predomina el biovar 3 y donde el ovino y el caprino son las principales especies afectadas y reservorio de la enfermedad, en la Argentina predomina el biovar 1 y la enfermedad afecta principalmente a los caprinos. En la Argentina se dispone de información sobre la presencia de brucelosis en caprinos y humanos desde el año 1922 (Villafañe y Lastra en Córdoba, citado por Mascaro, 1959). En Los Llanos de La Rioja fue descripta en 1941 por Oscar Fitte, y en Mendoza, Córdoba y el Chaco Semiárido salteño en las décadas posteriores.Estación Experimental Agropecuaria BarilocheFil: Robles, Carlos Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Area de Produccion Animal. Grupo de Sanidad Animal; ArgentinaFil: Gaido Analia Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Spath Ernesto Juan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Torioni, Susana Marta. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Grupo de Salud Animal; ArgentinaFil: Vanzini Victor Rene. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Grupo de Salud Animal; ArgentinaFil: Zielinski Gustavo Carlos. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez. Grupo de Salud Animal; ArgentinaFil: Aguirre, Daniel Hector. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta. Area de Salud Animal; ArgentinaFil: Samartino, Luis Ernesto. Instituto Nacional de Tecnología Agropecuaria (INTA). Centro de Investigacion en Ciencias Veterinarias y Agronomicas. Instituto de Investigacion Patobiologia; ArgentinaFil: Rossanigo, Carlos Esteban. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Villa Mercedes. Grupo de Salud Animal; Argentin

Walking on common ground: a cross-disciplinary scoping review on the clinical utility of digital mobility outcomes

Physical mobility is essential to health, and patients often rate it as a high-priority clinical outcome. Digital mobility outcomes (DMOs), such as real-world gait speed or step count, show promise as clinical measures in many medical conditions. However, current research is nascent and fragmented by discipline. This scoping review maps existing evidence on the clinical utility of DMOs, identifying commonalities across traditional disciplinary divides. In November 2019, 11 databases were searched for records investigating the validity and responsiveness of 34 DMOs in four diverse medical conditions (Parkinson’s disease, multiple sclerosis, chronic obstructive pulmonary disease, hip fracture). Searches yielded 19,672 unique records. After screening, 855 records representing 775 studies were included and charted in systematic maps. Studies frequently investigated gait speed (70.4% of studies), step length (30.7%), cadence (21.4%), and daily step count (20.7%). They studied differences between healthy and pathological gait (36.4%), associations between DMOs and clinical measures (48.8%) or outcomes (4.3%), and responsiveness to interventions (26.8%). Gait speed, step length, cadence, step time and step count exhibited consistent evidence of validity and responsiveness in multiple conditions, although the evidence was inconsistent or lacking for other DMOs. If DMOs are to be adopted as mainstream tools, further work is needed to establish their predictive validity, responsiveness, and ecological validity. Cross-disciplinary efforts to align methodology and validate DMOs may facilitate their adoption into clinical practice