Low back muscle action potential conduction velocity estimated using high-density electromyography

While a decreasing spectral content of surface electromyography reflects low back muscle fatigue development, reliability of these decreases may be insufficient. Decreasing frequency content is largely determined by decreasing average motor unit action potential conduction velocities (CV), which is considered a more direct measure of muscle...

Selecting the appropriate input variables in a regression approach to estimate actively generated muscle moments around L5/S1 for exoskeleton control

Back support exoskeletons are designed to prevent work-related low-back pain by reducing mechanical loading. For actuated exoskeletons, support based on moments actively produced by the trunk muscles appears a viable approach. The moment can be estimated by a biomechanical model. However, one of the main challenges here is the feasibility of...

Evaluation of a passive exoskeleton for static upper limb activities

The aim of this study was to evaluate the effect of a passive upper body exoskeleton on muscle activity, perceived musculoskeletal effort, local perceived pressure and subjective usability for a static overhead task. Eight participants (4 male, 4 female) held a load (0 kg and 2 kg) three times overhead for a duration of 30 s each, both with and...

Assessment of an active industrial exoskeleton to aid dynamic lifting and lowering manual handling tasks

The aim of this study was to evaluate the effect of an industrial exoskeleton on muscle activity, perceived musculoskeletal effort, measured and perceived contact pressure at the trunk, thighs and shoulders, and subjective usability for simple sagittal plane lifting and lowering conditions. Twelve male participants lifted and lowered a box of 7...

The effects of a passive exoskeleton on muscle activity, discomfort and endurance time in forward bending work

Exoskeletons may form a new strategy to reduce the risk of developing low back pain in stressful jobs. In the present study we examined the potential of a so-called passive exoskeleton on muscle activity, discomfort and endurance time in prolonged forward-bended working postures.Eighteen subjects performed two tasks: a simulated assembly task...

Estimation of low back moments from video analysis: A validation study

This study aimed to develop, compare and validate two versions of a video analysis method for assessment of low back moments during occupational lifting tasks since for epidemiological studies and ergonomic practice relatively cheap and easily applicable methods to assess low back loads are needed. Ten healthy subjects participated in a protocol...

International standards on working postures and movements ISO 11226 and EN 1005-4

Standards organizations have given considerable attention to the problem of work-related musculoskeletal disorders. The publication of international standards for evaluating working postures and movements, ISO 11226 in 2000 and EN 1005-4 in 2005, may be considered as a support for those involved in preventing and controlling these disorders. The...

Motion sickness provoked by torso rotation

Performance analysis of access selection and transmit diversity in multi-access networks

Motivated by the 'beyond 3G' vision of radio access network integration and coordinated radio resource management, a purely analytical performance assessment is presented for a single access point integrating multiple radio accesses. Principal focus is placed on the evaluation of multi-user diversity, multi-access diversity and trunking gains....

A new bricklayers' method for use in the construction industry

Objectives: The aim of this study was to investigate the effect of raised bricklaying on physical workload, reported musculoskeletal disorders, sickness absence, and job satisfaction. Methods: A controlled intervention study with a follow-up period of 10 months was performed among 202 bricklayers from 25 construction companies. Results: The...

Postmortem time estimation using body temperature and a finite-element computer model

In the Netherlands most murder victims are found 2-24 h after the crime. During this period, body temperature decrease is the most reliable method to estimate the postmortem time (PMT). Recently, two murder cases were analysed in which currently available methods did not provide a sufficiently reliable estimate of the PMT. In both cases a study...

High physical work load and low job satisfaction increase the risk of sickness absence due to low back pain: Results of a prospective cohort study

Objective: To determine whether physical and psychosocial load at work influence sickness absence due to low back pain. Methods: The research was a part of the study on musculoskeletal disorders, absenteeism, stress, and health (SMASH), a 3 year prospective cohort study on risk factors for musculoskeletal disorders. Workers from 21 companies...

Mechanisms of action of lumbar supports: A systematic review

Study Design. A systematic review and meta-analysis of studies on the putative mechanisms of action of lumbar supports in lifting activities. Objective. To summarize the evidence bearing on the putative mechanisms of action of lumbar supports. Summary of Background Data. A restriction of trunk motion and a reduction in required back muscle...

Cervically induced ocular torsion: Physiological and clinical aspects

Five healthy subjects were submitted to sinusoidal lateral tilt (amplitude 25° at frequency of 0.2Hz) of the whole body, only the head, or only the trunk about a vertical (subject in upright position) and about a horizontal axis (subject in supine position). The ocular torsioation of the neck by manipulating only the trunk had a negligible...

Application problems of a biomechanical model in improving roofwork

The compression force during traditional roofwork and improved roofwork was calculated by means of a two-dimensional static biomechanical model. The improvement resulted in a 30% reduction in compression force, but also influenced factors which cannot be incorporated into the model but may cause back injuries. The frequency and velocity of...

Doppler haematotachographie: interpretatieproblemen env nieuwe mogelijkheden