Psychophysically determined 1-h load carrying capacity of Chinese females

Abstract This study used psychophysical approach to examine the effects of container width, carrying rate, and distance on the maximum acceptable weight carried (MAWC) and the resulting responses (heart rate and rating of perceived exertion) to a 1-h work period of carrying tasks. After training, 12 Chinese females performed 27 different load-carrying tasks in random order. The conditions examined were container width (24.7, 35.6 and 46.5 cm), carrying rate (22.5, 36.0 and 49.5 s per carry), and distance (2.1, 3.5 and 4.9 m per carry). The results obtained lead to the following conclusions: (1) The container width significantly affected the MAWC, heart rates and overall RPE values. Although the heart rates increased with the container width, the MAWC and the overall RPE values did not decrease with the container width. (2) The carrying rate had significant effects on the MAWC, heart rate and overall RPE values. The MAWC declined with an increase in the carrying rate. However, the heart rate and RPE values increased with the carrying rate. (3) The carrying distance significantly affected the MAWC, heart rate, but had no significant effect on the overall RPE values. The MAWC decreased with an increase in the carrying distance and the heart rate increased with the carrying distance. (4) Both the carrying rate with container width and the carrying rate with distance had significant interaction effects on the MAWC. (5) The mean carrying heart rate of the subjects was approximately 53.6% of their maximum heart rates and the mean predicted carrying oxygen consumption was about 29.4% of V O 2 max. The most stressed body parts were the legs (RPE=13.5). (6) The MAWCs of Chinese females were 61% of the MAWC for Chinese males. Relevance to industry The results of this work can be used to design safe manual carrying tasks for Chinese females.

[1]  Fereydoun Aghazadeh,et al.  Psychophysical determination and modeling of load carrying capacity , 1994 .

[2]  G. Borg.  Physical performance and perceived exertion , 1962 .

[3]  P. Dempsey,et al.  A critical review of biomechanical, epidemiological, physiological and psychophysical criteria for designing manual materials handling tasks. , 1998, Ergonomics.

[4]  R. Bruce.  Exercise testing of patients with coronary heart disease. Principles and normal standards for evaluation. , 1971, Annals of clinical research.

[5]  M. H. Pope.  DOES MANUAL MATERIALS HANDLING CAUSE LOW-BACK PAIN? , 1998 .

[6]  R Ortengren,et al.  An ergonomic study of work methods and physical disorders among professional butchers. , 1987, Applied ergonomics.

[7]  R. D. Ray,et al.  Trends in Ergonomics/Human Factors II , 1985 .

[8]  S H Snook,et al.  Maximum weights and work loads acceptable to male industrial workers. A study of lifting, lowering, pushing, pulling, carrying, and walking tasks. , 1970, American Industrial Hygiene Association journal.

[9]  S H Snook,et al.  The effects of heat stress on manual handling tasks. , 1974, American Industrial Hygiene Association journal.

[10]  Arunkumar Pennathur,et al.  Nonfatal occupational injuries in the United States Part I – overall trends and data summaries , 2000 .

[11]  S H Snook,et al.  A Study of Size, Distance, Height, and Frequency Effects on Manual Handling Tasks , 1983, Human factors.

[12]  H. A. Dahl,et al.  Textbook of Work Physiology: Physiological Bases of Exercise, Fourth Edition , 2003 .

[13]  S P Wu,et al.  Psychophysical modelling of lifting capacity of Chinese males using strength variables. , 1993, Applied ergonomics.

[14]  Anil Mital,et al.  Influence of container shape, partitions, frequency, distance, and height level on the maximum acceptable amount of liquid carried by males , 1982 .

[15]  Anil Mital,et al.  A psychophysiological study of high and very high frequency manual materials handling: Part II - Carrying and turning , 1993 .

[16]  L Noro,et al.  Medical aspects of weight carrying. , 1967, Industrial medicine & surgery.

[17]  Anil Mital,et al.  Load Characteristics and Manual Carrying Capabilities , 1983 .

[18]  S H Snook,et al.  The design of manual handling tasks: revised tables of maximum acceptable weights and forces. , 1991, Ergonomics.

[19]  A Mital,et al.  Subjective estimates of one-handed carrying tasks. , 1983, Applied ergonomics.

[20]  Ciriello Vm,et al.  The effects of task duration on psychophysically-determined maximum acceptable weights and forces , 1990 .

[21]  S P Wu,et al.  Maximum acceptable weight of lift by Chinese experienced male manual handlers. , 1997, Applied ergonomics.

[22]  S J Morrissey,et al.  Maximum acceptable weights in load carriage. , 1988, Ergonomics.

[23]  S P Wu,et al.  Psychophysical determination of load carrying capacity for a 1-h work period by Chinese males , 2001, Ergonomics.

[24]  M M Ayoub,et al.  Psychophysical modelling for combined manual materials-handling activities. , 1986, Ergonomics.

[25]  Stover H. Snook,et al.  The Ergonomics Society The Society's Lecture 1978. THE DESIGN OF MANUAL HANDLING TASKS , 1978 .