Análisis electromiográfico de la actividad muscular de tronco durante el lanzamiento de bala paralímpico / Electromyographic analysis of trunk muscle activity during the Paralympic shot put / Análise electromiográfica da actividade muscular do tronco durante o lançamento de balas paraolímpicas

RESUMEN La estabilidad de la pelvis y el tronco, dada por la actividad de los músculos de la región, representa un factor importante para la correcta ejecución de la técnica deportiva y la prevención de lesiones en lanzadores paralímpicos. El objetivo de este estudio fue analizar a través de electromiografía de superficie, la actividad muscular del recto abdominal, oblicuo externo del abdomen y erector de la columna, vientres longuísimo e iliocostal, durante el lanzamiento de bala desde silla, en 4 atletas paralímpicos (2 con lesión en miembros inferiores y 2 con lesión medular). La electromiografía evidenció variaciones en los patrones de activación, el tiempo de ejecución y la amplitud de la señal, acorde a la condición de discapacidad y el grado de afectación del tronco. Esto permitió tener un panorama más real de las acciones musculares durante el gesto deportivo y la detección de opciones de mejora para los deportistas.

ABSTRACT The stability of the pelvis and trunk, given by the activity of the muscles in the region, represents an important factor for the correct execution of the sports technique and the prevention of injuries in Paralympic throwers. The objective of this study was to analyze, through surface electromyography the muscular activity of the rectus abdominis, external oblique of the abdomen and erector spinae, longuissimus and iliocostal bellies, during the shot put from a chair; in 4 Paralympic athletes (2 with lower limb injury and 2 with spinal cord injury). Electromyography showed variations in activation patterns, execution time and amplitude of the signal, according to the disability condition and the degree of trunk involvement. This allowed to have a more realistic panorama of the muscular actions during the sport gesture and the detection of improvement options for the athletes.

RESUMO A estabilidade da pélvis e do tronco, dada pela actividade dos músculos da região, representa um factor importante para a correcta execução da técnica desportiva e a prevenção de lesões nos lançadores paraolímpicos. O objectivo deste estudo foi analisar; através da electromiografía de superfície, a actividade muscular do recto abdominal, oblíquo externo do abdómen e erector da coluna vertebral, barriga muito comprida e iliocostal, durante o tiroteio em 4 atletas paraolímpicos (2 com lesão nos membros inferiores e 2 com lesão na medula espinal). A electromiografía mostrou variações nos padrões de activação, tempo de execução e amplitude do sinal, de acordo com a condição de incapacidade e o grau de envolvimento do tronco. Isto permitiu-nos ter uma imagem mais real das acções musculares durante o gesto desportivo e a detecção de opções de melhoria para os atletas.

Impact of Lifting of Two Types of Barrels on Postural Control, Trunk Muscle Recruitment, and Kinematic Measures in Manual Workers.

The aim of this study was to evaluate the impact of 2 types of beer barrels on postural control, trunk activation, and kinematic measures in adult workers. Twelve (12) males randomly performed 4 tasks on a force platform for 20 s: (1) hold an empty recyclable barrel, (2) hold a full recyclable barrel (30 L), (3) hold an empty steel barrel, and (4) hold a full steel barrel (30 L). Trunk muscular activation, force platform and kinematic measures at the trunk, hip, and knee joints were computed. The full steel barrel produced greater postural oscillation than other conditions. Higher trunk activity was also reported during the full steel barrel task. Significant kinematic changes only in the trunk were observed between the empty steel barrel and the full recyclable barrel tasks. In conclusion, the full steel barrel produced a negative impact on postural control, increasing trunk activity and changing trunk flexion angle in adult workers.

Control of a robotic knee exoskeleton for assistance and rehabilitation based on motion intention from sEMG

Introduction: This work presents the development of a novel robotic knee exoskeleton controlled by motion intention based on sEMG, which uses admittance control to assist people with reduced mobility and improve their locomotion. Clinical research remark that these devices working in constant interaction with the neuromuscular and skeletal human system improves functional compensation and rehabilitation. Hence, the users become an active part of the training/rehabilitation, facilitating their involvement and improving their neural plasticity. For recognition of the lower-limb motion intention and discrimination of knee movements, sEMG from both lower-limb and trunk are used, which implies a new approach to control robotic assistive devices. Methods A control system that includes a stage for human-motion intention recognition (HMIR), based on techniques to classify motion classes related to knee joint were developed. For translation of the user's intention to a desired state for the robotic knee exoskeleton, the system also includes a finite state machine and admittance, velocity and trajectory controllers with a function that allows stopping the movement according to the users intention. Results The proposed HMIR showed an accuracy between 76% to 83% for lower-limb muscles, and 71% to 77% for trunk muscles to classify motor classes of lower-limb movements. Experimental results of the controller showed that the admittance controller proposed here offers knee support in 50% of the gait cycle and assists correctly the motion classes. Conclusion The robotic knee exoskeleton introduced here is an alternative method to empower knee movements using sEMG signals from lower-limb and trunk muscles.