The acceptable load while marching at a speed of 5 km h-1 for young Chinese males

Ninety-three young Chinese men selected at random were involved in the load carrying experiments. They marched at 5 km h-1 carrying loads of 0, 15, 20, 25 and 31 kg for 7 h per day. At this speed the acceptable load to be carried was 20 kg. Under this load 95% of the men had heart rates below 120 bt min-1 while marching and energy metabolism was in balance. Nevertheless, 10-15% of the men were fatigued and felt tired.     

The effect of aerodynamic handlebars on oxygen consumption while cycling at a constant speed

Abstract

In this study, the oxygen consumption ([Vdot]O₂) of bicycling was measured at a fixed speed (40 km·h^?1on level terrain, with normal and aerodynamic handlebars using a Douglas bag collection system. Eleven elite (USCF category I or 2) men cyclists age 24 to 40 years (X¯=28·5, SD±4·6) performed four consecutive (two with each bar in alternating order) steady state rides at 40 km· h^?1over a 4 km flat course (same direction each trial). Expired gases were collected in a 1501 Douglas bag attached to a following vehicle during the last 45 s (approx. 0·5 km) of each trial. A repeated measures analysis of variance revealed a significant (p<0·02) handlebar effect. Specifically, [Vdot]O₂was 2% lower under the aerodynamic handlebar treatment (X¯=4·26, SD±0·36 1 min^?1when compared with that of the normal handlebar treatment (X¯=4·34, SD±0·35 1 min^?1The results of this study demonstrate that the reported aerodynamic advantage of the aerodynamic handlebars produces a small but significant reduction in the [Vdot]O₂of bicycling at 40 km·h^?1     

Maximum acceptable weights for asymmetric lifting of Chinese females

This study used the psychophysical approach to evaluate the effects of asymmetric lifting on the maximum acceptable weight of lift (MAWL) and the resulting heart rate, oxygen uptake and rating of perceived exertion (RPE). A randomized complete block factorial design was employed. Twelve female college students lifted weights at three different lifting frequencies (one-time maximum, 1 and 4 lifts/min) in the sagittal plane and at three different asymmetric angles (30 degrees, 60 degrees, and 90 degrees ) from the floor to a 68-cm height pallet. This lifting experiment was conducted for a 1-h work period using a free-style lifting technique. The MAWLs for asymmetric lifting were significantly lower than those for symmetric lifting in the sagittal plane. The MAWL decreased with the increase in the angle of asymmetry. However, the heart rate, oxygen uptake and RPE remained unchanged. Though the MAWL decreased significantly with lifting frequency, both the physiological costs (heart rate and oxygen uptake) and rating of perceived exertion increased with the increase in lift frequency. The most stressed body part was the arm. Lifting frequency had no significant effect on the percentage decrease in MAWL from the sagittal plane values. On average, decreases of 5%, 9% and 14% for MAWL at 30 degrees, 60 degrees and 90 degrees asymmetric lifting, respectively, were revealed. This result was in agreement with the findings of Chinese males studied by Wu [Int. J. Ind. Ergonom. 25 (2000) 675]. The percentage decrease in MAWL with twisting angle for the Chinese participants was somewhat lower than those for Occidental participants. In addition, even though there was an increase in heart rate and RPE with the increase in the symmetrical lift angle for Occidental participants, it was different from the Chinese participants. Lastly, the 1991 NIOSH equation asymmetry multiplier is more conservative in comparison with the results of the present study.     

The Ergonomics Research Society THE SOCIETY'S LECTURE, 1974* The Borderland of Anatomy and Ergonomics

A survey of The status of ergonomics in Poland was conducted over a three week period during July 1978 under the sponsorship of the National Academy of Sciences scientific exchange programme. Ergonomic activities were reviewed in Warsaw and Cracow by means of a series of visits to academic and research institutions. Among the organizations contacted were: the Institute of Industrial Design, the Polish Psychological Association, the Institute of Psychology at the University of Warsaw, the Academy of Fine Arts in Cracow and The Institute of Psychology associated with the Jagiellonian University. Based on interviews with prominent scientists in the forefront of ergonomic activities, the report provides a review of the historical development of ergonomics, the composition of the ergonomics community, current research interests and applications, and anticipated future trends. The Poles claim credit for having coined the term Ergonomics in 1857. They are proud to have formed the first Ergonomics Society in the Eastern European bloc of nations. Its current membership totals over 400 and they look forward to hosting the 1979 International Ergonomics Association meeting in Warsaw. There are only about 100 engineering psychologists in Poland. Engineers and physiologists or physicians tend to dominate the ergonomics field. There appears to be strong support for this emerging discipline from the State and industrial enterprises and ergonomics can be expected to become increasingly more important in Poland.     

The physical strain of dairy farming

The aim of this study was to estimate the physical stress and strain in dairy farming, using ambulatory heart rate and oxygen consumption measurements. The rate of perceived exertion was estimated with Borg scale. The maximal oxygen consumption was measured in the laboratory. The study group consisted of eight male and 15 female farmers. The handling of feed and manure was the heaviest work task in dairy farming. The aerobic capacity ([Vdot]O₂ max) of female farmers (26 ± 3 ml/min/kg) was below average, and their work required over 50% of [Vdot]0₂ max during most of the tasks. The [Vdot]0₂ max of male fanners (32±10 ml/min/kg) was moderate, and most work tasks required below 50% of [Vdot]0₂ max. The mean heart rate in dairy farming tasks was 99 beats min^-1 in men and 116 beats min^-1 in women. However, according to the rate of perceived exertion, the men experienced the same work tasks as subjectively more heavy than did the women. The physical strain of female farmers in dairy farming seems to be too high because of heavy work tasks and relatively low [Vdot]0₂ max of women. Special attention should be paid to these factors in the occupational health services for farmers.     

Psychophysically determined symmetric and asymmetric lifting capacity of Chinese males for one hour''s work shifts

A laboratory experiment was conducted to determine the effects of asymmetric lifting on psychophysically determined maximum acceptable weight of lift (MAWL) and the resulting heart rate, oxygen uptake and rating of perceived exertion. Thirteen male college students were recruited as participants. Each participant performed 12 different lifting tasks involving three lifting frequencies (one-time maximum, 1 and 4 lifts/min) and four twisting angles (including the sagittal plane and three different angles of asymmetry, i.e., 0, 30, 60, and 90°) from the floor to a 76 cm high pallet for one hour's work shift using a free-style lifting technique. The results showed that: (1) The MAWLs were significantly lower for asymmetric lifting than for symmetric lifting in the sagittal plane. The MAWL decreased with an increase in the angle of asymmetry, however, the heart rate, oxygen uptake and RPE remained unchanged; (2) Lifting frequency had no significant effect on the percentage decrease in MAWL from the sagittal plane values. Correction factors of 4, 9, and 13% for MAWL at 0, 30, 60, and 90°of asymmetric lifting, respectively, are recommended; (3) Both the physiological costs (heart rate and oxygen uptake) and rating of perceived exertion increased with an increase in lifting frequency though maximum acceptable weight of lift decreased. The most stressed body parts were the lower back and the arm; and (4) The percentage decrease in MAWL with twisting angle for the Chinese participants was somewhat lower than those of the Occidental participants. In addition, even though there was a decrease in MAWL, heart rate and RPE increased with an increase in the angle of a symmetric lifting for the Occidental participants, it was different from that of the Chinese participants.

Relevance to industry

It is generally believed that asymmetric lifting involving torso twisting is more harmful to back spine than symmetric lifting. However, the previous studies were conducted in Europe and North America, and the data were obtained from the Caucasian populations. This work, therefore, aims to investigate the influence of asymmetric lifting on the lifting capacity of the Chinese participants, and to compare the differences with the Occidental populations.