Electromyographic study of the arms in competitive karting senior category drivers / Estudio electromiográfico de los brazos en pilotos senior de karting de competición

The main goal of this cross-sectional study was to assess the muscular activity of the upper limbs in competitive kart drivers while driving in a closed karting circuit, using surface electromyography (EMGS). The most significant muscles of the upper limbs while driving were evaluated in thirteen drivers. Linear mixed models adjusted to a gamma distribution were used to evaluate differences in muscle activity based on the arm, number of laps, track characteristics, and kart type (with/without gears). Significant differences were found between muscle activity according to the type of kart (p <0.0001). Although changes were observed in the mean EMGS values, there were no significant differences between the laps of the circuit or the dominant arm. However, the results showed that there was a significant interaction between the type of kart and the dominant arm (p = 0.021). Muscle activity increased more significantly in the curves traced towards the dominant arms of the drivers (AU)

El objetivo del estudio transversal fue analizar la actividad muscular de las extremidades superiores en pilotos senior de karting de competición, mediante electromiografía de superficie (EMGS). Se evaluaron los músculos más significativos de las extremidades superiores durante la conducción en trece conductores. Se utilizaron modelos lineales mixtos ajustados a una distribución gamma para evaluar diferencias de actividad muscular en base al brazo, número de vueltas, características del trazado, y tipo de kart (con/sin marchas). Se encontraron diferencias significativas entre la actividad muscular según el tipo de kart (p<0,0001). Aunque se observaron cambios en los valores medios de EMGS, no hubo diferencias significativas entre las vueltas del circuito o el brazo dominante. Sin embargo, los resultados mostraron que hubo una interacción significativa entre el tipo de kart y el brazo dominante (p=0,021). La actividad muscular aumentó de manera más significativa en las curvas trazadas hacia el brazo dominante de los conductores (AU)

Proximate causes of the red face of the bald uakari monkey (Cacajao calvus).

In social species, such as primates, facial appearances transmit a variety of social signals. Although it is suggested that the intense red colour of the face of the bald uakari monkey might be an indicator of health, this hypothesis still has not been verified. This study describes the histological structure of the skin of the face in the bald uakari, compared with other non-red neotropical primates, to better understand the maintenance of its colour. The facial skin of the bald uakari monkey is characterized by a thinner epidermis, absence of melanin pigments and a high density of vascular capillaries that spread below the epidermis. These vascular capillaries are larger and more tortuous than in other neotropical primates. The skin of the face of the bald uakari monkey allows a direct external assessment of haematological status, suggesting that the colour of the face would be an honest indicator of health, but could also signal sexual or behavioural states.