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Biomedical subjects

S S Asfour

Publications and source records attributed to S S Asfour.

26 records · Page 2Linked to original sources
PubMed1986

Physiologic responses to static, dynamic and combined work.

The main objective of the present study was to determine the effects on cardiovascular stress of tasks that have varying degrees of static and dynamic components (weight holding, manual lifting and stepping). Heart rate, oxygen consumption and blood pressure were used as indices of cardiovascular stress. The results showed that oxygen consumption and heart rate responses to manual lifting are significantly lower than those of stepping and higher than those of weight holding. A low frequency lifting task evoked significantly lower systolic blood pressure than a high frequency lifting task. This study supported the idea that a physiologic fatigue criterion (PFC) based on stepping should not be applied directly to tasks such as manual lifting. In addition, a PFC for manual lifting should not be based only on oxygen consumption or heart rate; it also should incorporate systolic blood pressure as one of the monitored stress factors in setting lifting standards.

Adult↗
PubMed1985

Physiological limits in lifting.

Two different experiments were conducted to study the effects of frequency, height and load of lift on computed maximal oxygen uptake and to compare the data obtained to a standard bicycle ergometer. A progressive submaximal technique was used to predict maximal oxygen uptake. The results of the present study revealed that across all heights, an increase in either the frequency of lift or load of lift was accompanied by an increase in computed maximal oxygen uptake; however, all maximal oxygen uptake values reported showed a tendency to level off beyond the frequency of five lifts/min. The results also showed that combined arm and leg lifting recorded the highest maximal oxygen uptake followed by leg lifting then arm lifting, respectively. Maximal oxygen uptake values obtained for lifting tasks were much lower than those obtained for a bicycle ergometer. It is therefore recommended that limits for continuous work for a lifting task be based on the attainable maximal oxygen uptake for that particular task and not on a maximal oxygen uptake obtained from another task such as a bicycle ergometer test.

Adult↗
PubMed1983

Perceived exertion of physical effort for various manual handling tasks.

Ten trained male students between 18 and 28 years of age participated in a study, designed to determine the relationship between perceived exertion and physiological costs of exertion during various manual lifting and lowering tasks. Perceived exertion was defined as one's subjective rating of the intensity of work being performed. Five subjects performed lifting tasks and another five performed lowering tasks. Weight of load lifted or lowered (6.8, 13.6, 20.5 kg), frequency of lift or lower (3, 6, 9 times/min), height of lift or lower (floor to 76 cm, 76 to 127 cm, floor to 127 cm), box width (38, 66 cm), box length (38, 66 cm) and angle of twist of the body (0 degree, 90 degrees) were the independent variables studied. Heart rate, oxygen consumption, and ratings of perceived exertion (RPE) were the response measures. RPE was found almost linearly related to heart rate and oxygen consumption when lifting or lowering loads. For lifting tasks, the coefficient of correlation between RPE and heart rate was 0.673. In the case of lowering tasks, this coefficient was 0.604. When oxygen consumption was considered, the corresponding coefficients for lifting and lowering were 0.734 and 0.619, respectively. The correlation of RPE with the physiological response variables indicates that the severity of manual materials handling tasks in industry can be evaluated quickly and inexpensively by using perceived exertion ratings (RPE).

Adolescent↗