Biomedical subjects

S N MacKinnon

Publications and source records attributed to S N MacKinnon.

2 recordsLinked to original sources

PubMed1999

Relating heart rate and rate of perceived exertion in two simulated occupational tasks.

The purpose of this study was to examine the relationship between ratings of perceived exertion (RPE) and activity intensity, as determined by heart rate. Fifteen participants completed a standardized treadmill protocol in order to establish a heart rate--RPE calibration profile. These participants then completed two simulated occupational tasks--box carrying and sweeping. During the simulated tasks, heart rates and RPE values were recorded every minute from the third to tenth minute and then averaged over that period. There was a moderate, but statistically significant, correlation between monitored heart rate and heart rate predicted from RPE scores for both the box carrying (r = 0.70) and sweeping (r = 0.73) simulations. Direct prediction of task heart rate from RPE reported during the task was not as strongly correlated for the box carry (r = 0.11), as it was for the sweeping activity (r = 0.68). Results from this study suggested that heart rate monitoring alone does not account for enough of the variability resulting from both local and central mediation of RPE.

Activities of Daily Living↗

PubMed1998

Isometric pull forces in the sagittal plane.

This paper investigates the differences in maximal isometric horizontal pull forces in the sagittal plane about a frontal plane work envelope. Eight subjects produced maximal isometric horizontal pulls about 32 positions in the frontal for each of three different postural conditions: free standing, fixed standing and seated. Four horizontal positions (0, 200, 400, 600 mm relative to the mid-line of the body) in the sagittal plane at four vertical heights in two standing postures (1070, 1470, 1610, 2000 mm from the floor) and one sitting posture (220, 620, 760, 1150 mm from a seated reference position) were tested for both the left and right hand under all three postural conditions. Experimental findings reveal that the largest horizontal forces were produced at a height of 1070 mm in the standing postures and 220 mm in the sitting posture and were within 200 mm to the left and right of the mid-line of the body. These findings confirm that work-station designs should position heavy materials near the mid-line of the body, at or about elbow height to take advantage of operator's force-producing capabilities in the sagittal plane.

Adult↗