Biomedical subjects

D Roman-Liu

Publications and source records attributed to D Roman-Liu.

3 recordsLinked to original sources

PubMed2001

Assessment of the musculoskeletal load of the trapezius and deltoid muscles during hand activity.

The purpose of the study was to analyse the influence of the precision of a task on tension and fatigue of the trapezius and deltoid muscles. Ten young men took part in experiments. Different levels of force and different frequencies of pressing a button defined the precision of the task. Surface electromyography (EMG) was used. Muscle tension and fatigue were reflected by 2 parameters of the EMG signal: the Root Mean Square amplitude related to the maximum value and changes in the Median Power Frequency. The results showed that hand activities influence the descending part of the trapezius muscle and do not influence the deltoid muscle, and that the precision of work can influence the examined muscles of the arm and shoulder even during work in which only the hand is involved in a performed task.

Adult↗

PubMed1999

Computerized method for work space optimization in conditions of static work.

The aim of this research was to develop a theoretical method for the ergonomic optimization of the work space of the upper limb. This method is based on a model of the upper extremity with 7 degrees of freedom. It consists of 3 rigid elements modeling the arm, forearm, and hand and 34 upper extremity muscles. The trunk is considered immobile. The shoulder joint is modeled as a rotating kinematics pair of third class, the elbow and wrist joints--of fourth class. The minimum sum of muscle force moments in the joints and soft saturation muscle cooperation criterion were used as merit criteria. The developed method makes it possible to effectively solve, in a defined work space, the task of work space optimization.

Arm↗

PubMed1999

Experimental verification of the computerized method for work space optimization in conditions of static work.

The aim of this study was to verify a theoretical model for upper extremity work space optimization. In order to do that, experimental studies were conducted in which two parameters of the electromyography (EMG) signal were analyzed: AMP (amplitude calculated as Root Mean Square) and SZC (coefficient of the slope of the regression line between time and Zero Crossing values). Values of forces in muscles (parameter MOD) were calculated from theoretical studies. A comparison of experimental (AMP, SZC) and theoretical (MOD) parameters was performed by analyzing the coefficient of correlation between those parameters and differentiation of muscular load according to external load value. Analysis showed that the theoretical and experimental results are in step, which means that the developed model can be used for upper extremity work space optimization.

Adult↗