Biomedical subjects

M Douwes

Publications and source records attributed to M Douwes.

7 recordsLinked to original sources

PubMed2001

Are neck flexion, neck rotation, and sitting at work risk factors for neck pain? Results of a prospective cohort study.

OBJECTIVE: To study the relation between neck pain and work related neck flexion, neck rotation, and sitting. METHODS: A prospective cohort study was performed with a follow up of 3 years among 1334 workers from 34 companies. Work related physical load was assessed by analysing objectively measured exposure data (video recordings) of neck flexion, neck rotation, and sitting posture. Neck pain was assessed by a questionnaire. Adjustments were made for various physical factors that were related or not related to work, psychosocial factors, and individual characteristics. RESULTS: A significant positive relation was found between the percentage of the working time in a sitting position and neck pain, implying an increased risk of neck pain for workers who were sitting for more than 95% of the working time (crude relative risk (RR) 2.01, 95% confidence interval (95% CI) 1.04 to 3.88; adjusted RR 2.34, 95% CI 1.05 to 5.21). A trend for a positive relation between neck flexion and neck pain was found, suggesting an increased risk of neck pain for people working with the neck at a minimum of 20 degrees of flexion for more than 70% of the working time (crude RR 2.01, 95% CI 0.98 to 4.11; adjusted RR 1.63, 95% CI 0.70 to 3.82). No clear relation was found between neck rotation and neck pain. CONCLUSION: Sitting at work for more than 95% of the working time seems to be a risk factor for neck pain and there is a trend for a positive relation between neck flexion and neck pain. No clear relation was found between neck rotation and neck pain.

Cohort Studies↗

PubMed2000

Flexion and rotation of the trunk and lifting at work are risk factors for low back pain: results of a prospective cohort study.

STUDY DESIGN: A 3-year prospective cohort study among workers of 34 companies in the Netherlands. OBJECTIVES: To investigate the relation between flexion and rotation of the trunk and lifting at work and the occurrence of low back pain. SUMMARY OF BACKGROUND DATA: Previous studies on work-related physical risk factors for low back pain either lacked quantification of the physical load or did not take confounding by individual and psychosocial factors into account. METHODS: The study population consisted of 861 workers with no low back pain at baseline and complete data on the occurrence of low back pain during the 3-year follow-up period. Physical load at work was assessed by means of analyses of video-recordings. Information on other risk factors and the occurrence of low back pain was obtained by means of self-administered questionnaires. RESULTS: An increased risk of low back pain was observed for workers who worked with the trunk in a minimum of 60 degrees of flexion for more than 5% of the working time (RR 1.5, 95% CI 1.0-2.1), for workers who worked with the trunk in a minimum of 30 degrees of rotation for more than 10% of the working time (RR 1.3, 95% CI 0.9-1. 9), and for workers who lifted a load of at least 25 kg more than 15 times per working day (RR 1.6, 95% CI 1.1-2.3). CONCLUSIONS: Flexion and rotation of the trunk and lifting at work are moderate risk factors for low back pain, especially at greater levels of exposure.

Adult↗

PubMed2000

[Cesar therapy is temporarily more effective in patients with chronic low back pain than the standard treatment by family practitioner: randomized, controlled and blinded clinical trial with 1 year follow-up].

OBJECTIVE: To determine the effectiveness of a special form of exercise therapy ('Cesar therapy') on self reported recovery and improvement of posture amongst patients with chronic aspecific lower back pain. DESIGN: Prospective randomized controlled and blinded investigation. METHOD: After informed consent had been obtained, patients with chronic aspecific lower back pain were given, on a randomized basis, either an exercise therapy (experimental group, n = 112) or a standard treatment by their general practitioner (control group, n = 110). Outcome measures were self reported recovery of back pain and improvement of posture (thoracic and lumbar spine, pelvis). Self reported recovery was determined by means of a dichotomized 7-point scale (questionnaire). Posture was measured qualitatively by a panel of 11 Cesar therapists (blinded) and quantitatively by an optical-electronic posture recording system (Vicon). Measurements were taken at baseline (pre-randomization) and at 3, 6 and 12 months after randomization. RESULTS: Three months after randomization, patients who were treated according to Cesar therapy, reported an improvement in their back symptoms (80%) significantly more often than the control group (47%). In both groups, however, only small improvements in posture were found. The judgement of the Cesar panel exhibited a significant difference between the two groups, with respect to the spine, in favour of Cesar therapy. Differences between the groups were still present 6 months after randomization, but could no longer be detected at 12 months after randomization. CONCLUSION: Cesar therapy was significantly more effective than standard treatment among patients with chronic lower back pain for a period of 6 months after randomization.

Adult↗

PubMed1994

Validity of a diary estimating exposure to tasks, activities, and postures of the trunk.

The validity of a diary that estimates exposure to tasks, activities, and postures of the trunk was determined by comparing these self-reported exposure data with observational data of a whole working day. Two populations were studied: 32 professional drivers and five nurses. The nurses and 16 drivers also filled out a shortened version of the diary during another working day. Both versions of the diary showed poor agreement with observations over the same period. However, for variables concerning activities and postures of the trunk agreement was improved by the shortening of the diary. It is concluded that in epidemiologic studies observational measurements of exposure cannot validly be replaced by diaries or similar self-reported exposure data, because the self-reports easily lead to misclassification.

Adult↗

PubMed1994

Evaluation of a sitting aid: the back-up.

The effects of a portable back support, the Back-Up, were tested in 28 variables. Both subjective and objective physical load measures were recorded during sitting with and without Back-Up, most of them during VDU work. The main result was that the posture of the upper back and neck/head was improved by the Back-Up. However, the knee straps induced unacceptable high pressure and increased significantly the discomfort in the legs. Based on these results the Back-Up was modified: the contact area between the strap and the knee was enlarged. This modified Back-Up was tested again for 13 variables with 10 new subjects. The knee pressure turned out to be acceptable and the discomfort was equal to sitting without the Back-Up. Based on this research the Back-Up is considered as a possible addition to more fundamental ergonomic improvements such as adjustable furniture and variation between sitting, standing and walking tasks, especially for improvement of the neck load. However, the Back-Up should not replace proper ergonomic workstation and work organization design or a backrest on the chair. Furthermore, the Back-Up should not be made obligatory, and it should be worn only for a part of the day, because it limits variation in postures.

Journal Article↗

PubMed1994

Ergonomic guidelines for the prevention of discomfort of static postures based on endurance data.

This communication aims to show why guidelines to prevent discomfort of static postures can be based on endurance data, and to give insight in the aim and scope of a recent 'work-rest model for static postures' (WR model). The paper is a response to a recent paper of Mathiassen and Winkel (1992) who questioned the usefulness of discomfort and endurance data, and of the WR model for developing guidelines for static postures. It is concluded that discomfort can be considered as an independent evaluation variable for working postures, anchored in European legislation. Discomfort can be predicted from the 'remaining endurance capacity' (REC) because of a known relationship between the REC and discomfort as measured with the Borg rating scale. The WR model estimates at group level the mean REC of a static posture with or without an external force during and immediately after a work-rest schedule. The WR model is meant to assist practitioners in the assessment and optimization of static postures (and external forces) and work-rest schedules in order to avoid high levels of discomfort.

Ergonomics↗

PubMed1993

Two-dimensional photographic posture recording and description: a validity study.

Posture recording and description is necessary to yield data by which postural load can be assessed. In this paper an inexpensive and simple method to gather these data is described, ie two-dimensional (2-D) posture recording and description by means of photography. A disadvantage of this method, perspective error, is discussed and guidelines are given to reduce it. The validity of the method was experimentally tested for a situation slightly conflicting with some guidelines, ie recording of the whole body, with a small distance between camera and subject. For this purpose posture recording with 2-D photography was compared with posture recording by means of a three-dimensional optoelectronic system (Vicon). In general, 2-D photographic posture recording and description is a valid method as long as some guidelines for reduction of perspective error are followed.

Journal Article↗