Biomedical subjects

Christine M Haslegrave

Publications and source records attributed to Christine M Haslegrave.

4 recordsLinked to original sources

PubMed2007

Developing a verbal protocol method for collecting and analysing reports of workers' thoughts during manual handling tasks.

Concurrent and retrospective verbal protocol methods were used to collect thoughts from 18 participants during a manual handling task involving the repeated transfer of loads between locations at two tables. The effectiveness of qualitative and quantitative methods of analysing the reported information was tested in the study. A simple taxonomy was developed to investigate the content of the reports (including reports on postures and loads) and determine how the participants approached the task (whether they made plans, described actions or evaluated their completion of the task). References to posture were obtained in the verbal protocol reports, indicating that the participants had some awareness of their postures during parts of the task. There were similarities in the content of the concurrent and retrospective reports, but there were differences in the amount of detail between the methods and differences in the way the reports were constructed. There could be some scope for developing the quantitative analysis of the frequencies of references to classes of information, though this can only be recommended for concurrent reports on tasks of short duration. The analyses of qualitative data gave a deeper insight into the reports, such as identifying factors that can be important when planning to handle a load, or illustrating how participants can change their focus of attention periodically throughout the task. The relative strengths of the concurrent and retrospective methods are described, along with ideas for improving the quality of information collected in future studies. A number of potential problems with the interpretation of the reported information are explained.

Communication↗

PubMed2006

Use of concurrent and retrospective verbal protocols to investigate workers' thoughts during a manual-handling task.

A manual handling task (an order picking task in a distribution warehouse) was investigated using concurrent verbal protocols and retrospective verbal protocols (applied at three different times after completion of the task). The study aimed to collect workers' thoughts during the task and to determine what workers are comfortable with reporting. Video recordings of the task were used as a means of investigating the accuracy of the information which was reported. The concurrent and retrospective verbal protocol methods were compared and it was found that concurrent reports could be used to collect a range of task related thoughts, although they only contained a proportion of the workers' thoughts during the task. Additional information could be obtained from retrospective reports, although these appeared to be vulnerable to bias and re-ordering of reported information. The retrospective reports produced whilst watching a video recording of the task were particularly vulnerable to bias from retrospective reasoning or the rationalisation of thoughts. Only one specific reference to posture or handling technique was made by any of the workers in their reports. There were also few references to load characteristics. Workers frequently reported aspects of the task that were easier to verbalise, such as the counting or labelling of items. It is not known whether the workers were only aware of these limited details of their tasks or whether they were only able to report limited details of the tasks because of factors affecting verbal reporting. This was an exploratory study which has collected valuable information from a small sample of experienced workers in relation to a common task from industry, but further study is needed to investigate the effects of factors such as load weight, load position and task duration on awareness and reporting of thoughts.

Adult↗

PubMed2003

Pouring liquid from a pot-kinematics of an everyday task.

An experiment was carried out to investigate the effects of handle design on postures in the use of pots. Six combinations of handle (sloping, vertical and curved) and spout designs (long and short) were tested during grasping, lifting and pouring. The fill load was 1000 ml of water at the prevailing room temperature (about 20 degrees C) and three males and three females were involved as subjects. Measurements were made of x- (horizontal), y- (lateral) and z- (vertical) co-ordinates of the wrist, elbow shoulder and hip joints in space throughout the motions, using a CODA MPX30 optical 3D measurement system and both linear and angular displacements of the arm joints and trunk were computed. Very different configurations of arm posture were found to be adopted at the moment of pot lift, and when pouring commences and the subjects' movement patterns during transfer of the pot to fill vessel showed to be influenced by the configuration of arm posture adopted at the moment of pot lift. For lifting the pot, the vertical handle design proved to be more desirable than either the curved or sloping design, while for pouring from the pot the short spout proved to be more desirable than the long spout, at least when the pot was full. The results are however, not clear on which handle or spout design is best for transferring the pot.

Biomechanical Phenomena↗

PubMed2003

Postures adopted when using a two-wheeled cylinder trolley.

Upper limb and trunk positions were investigated when subjects exerted force to start and move a two-wheeled cylinder trolley with four different handles. Three of the handles had orientations 35 degrees, 50 degrees and 70 degrees in the sagittal plane (relative to the back of the trolley). The fourth was the 50 degrees handles fitted with a link bar. Measurements were made of x (horizontal), y (lateral) and z (vertical) coordinates of the body joints in space throughout the motion, using a CODA MPX30 optical 3-D measurement system, and both linear and angular displacements were computed. The linear and angular positions of the body joints were found to change through the stages of the task. Orientation of the handle influenced the arm postures adopted in the task, and showed to produce different patterns of arm displacement in force exertion to tilt the trolley from standing position. For steady movement, the sagittal plane 50 degrees handle proved most desirable.

Arm↗