Occupational and non-occupational risk factors for neck and lower back pain among computer workers: a cross-sectional study.

The aim of this study was to identify major determinants for neck and lower back pain (LBP) among office workers of different ages. . Computer workers ( = 2000) responded to a questionnaire on demographics, musculoskeletal disorders (MSDs), lifestyle characteristics, ergonomics of computer work and psychosocial and physical job characteristics.

Experimental identification of a mathematical model of human operator working under mental stress.

In engineering the human is considered as one of the system elements. In most studies, his/her model remains unchanged due to the external factors. The present study shows that a relation between the mental stress and human dynamics cannot be neglected.

Influence of type of MVC test on electromyography measures of biceps brachii and triceps brachii.

Objective: This study aimed to investigate the amplitude and frequency measures of the electromyography (EMG) signal in agonistic and antagonistic muscles (biceps brachii, triceps brachii).

Methods: Fifteen males (22.9 ± 2.

Assessment of muscle load and fatigue with the usage of frequency and time-frequency analysis of the EMG signal.

The aim of the study was to determine the effect of the muscle load and fatigue on the values of the parameters calculated on the basis of the time, frequency (Fourier transform) and time-frequency (wavelet transform) analysis of the EMG signal, for low levels of load. Fifteen young men took part in the study. The EMG signal was registered from right side biceps brachii (BB) and trapezius (TR) muscles in static conditions, at load 10%, 20% and 30% MVC (maximal voluntary contraction).

Influence of upper extremity position on EMG signal measures calculated in time, frequency and time-frequency domains.

The aim of this study was to investigate the relationship between time-frequency, time and frequency measures when considering various upper extremity positions below the level of the shoulder and in trapezius as well as deltoideus muscles. During the experiment, 15 subjects performed a task that involved screwing and unscrewing a screw cap on a board in six different locations, i.e.

Heart rate variability (HRV) and muscular system activity (EMG) in cases of crash threat during simulated driving of a passenger car.

Objectives: The aim of the study was to verify whether simultaneous responses from the muscular and circulatory system occur in the driver's body under simulated conditions of a crash threat.

Materials And Methods: The study was carried out in a passenger car driving simulator. The crash was included in the driving test scenario developed in an urban setting.

The influence of wrist posture on the time and frequency EMG signal measures of forearm muscles.

This study investigates how altering wrist posture influences the relationship between the time and frequency measures of the electromyography (EMG) signal of extensor digitorum communis (EDC) and flexor carpi ulnaris (FCU). Thirteen participants exerted handgrip force related to maximum voluntary contraction (MVC) in four tests: 20%MVC and 50%MVC in neutral wrist posture and 20%MVC in full wrist flexion and extension. EMG measurements from EDC and FCU were used to calculate normalized values of amplitude (nRMS) and mean and median frequency of the power spectrum (nMPF, nMF).

The influence of fatigue on muscle temperature.

The aim of the study was to investigate the possibility of using infrared (IR) thermography for assessing muscle fatigue during low effort. Three tests at constant levels of load 5, 15 and 30% of maximum voluntary contraction (MVC) lasting 5 min each were performed on a group of 10 men. Temperature and electromyographic (EMG) signal were registered from biceps brachii (BB).

The effect of the fatty tissue on EMG signal in young women.

The aim of this study was to investigate the influence of fatty tissue layer on EMG signal parameters as a function of force level and type of muscle in young women. On the basis of body mass index (BMI) and the amount of fatty tissue (FT) 30 young women were divided into two equal groups: obese (O) and reference group (R). The EMG signal was measured on 5 levels of load from 2 muscles: palmaris longus (PL) and rectus abdominis (RA).

A study of the influence of muscle type and muscle force level on individual frequency bands of the EMG power spectrum.

The aim of this study was to analyse the electromyographic (EMG) power spectrum indicating differences in the frequency bands of the spectrum resulting from differences in muscle type and force level for the extensor digitorum (ED), palmaris longus (PL) and biceps brachii (BB) muscles. The study was performed on 12 young men as 2 tests different in terms of the type of exerted force (30, 15 and 5% MVC, maximum voluntary contraction). The parameters of the EMG power spectrum were obtained as a result of a division of the EMG power spectrum into ranges determined by border frequencies.