• Journal of the Ergonomics Society of Korea
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• v.32 no.5
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• pp.413-420
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• 2013

Objective: The objective of this study was to compare one-hand and two-hands lowering activity in terms of biomechanical stress for the range of lowering heights from knuckle height to 10cm above floor level. Background: Even though two-hands lifting/lowering activity of manual materials handling tasks are prevalent at the industrial site, many manual materials handling tasks which require the worker to perform one-hand lifting/lowering are also very common at the industrial site and forestry and farming. Method: Eight male subjects were asked to perform lowering tasks using both a one-handed as well as a two-handed lowering technique. Trunk muscle electromyographic activity was recorded while the subjects performed the lowering tasks. This information was used as input to an EMG-assisted free-dynamic biomechanical model that predicted spinal loading in three dimensions. Results: It was shown that for the left-hand lowering tasks, the values of moment, lateral shear force, A-P shear force, and compressive force were increased by the average 6%, as the workload was increased twice from 7.5kg to 15kg. For the right-hand lowering task, these were increased by the average 17%. For the two-hands lowering tasks, these were increased by the average 14%. Conclusion: Even though the effect of workload on the biomechanical stress for both one-hand and two-hands lowering tasks is not so significant for the workload less than 15kg, it can be claimed that the biomechanical stress for one-hand lowering is greater than for two-hands lowering tasks. Therefore, it can be concluded that asymmetrical lowering posture would give greater influence on the biomechanical stress than the workload effect for one-hand lowering activity. Application: The result of this study may be used to provide guidelines of recommended safe weights for tasks involved in one-hand lowering activity.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.4
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• pp.72-81
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• 2014

Even though two-hands lifting/lowering activity of manual materials handling tasks are prevalent at the industrial site, many manual materials handling tasks which require the worker to perform one-hand lifting/lowering are also very common at the industrial site, forestry, farming, and daily life. The objective of this study was to compare one-hand lowering activity to lifting activity in terms of biomechanical stress for the range of lowering heights from knuckle height to 10cm above floor level with two workload 7.5kg and 15.0kg. Eight male subjects with LMM were asked to perform lifting/lowering tasks using both a one-handed (left-hand and right-hand) as well as a two-handed technique. Spinal loading was estimated through an EMG-assisted free-dynamic biomechanical model. The biomechanical stress of one-hand lowering activity was shown to be 43% lower than that of one-hand lifting activity. It was claimed that the biomechanical stress for one-hand lifting/lowering activity is almost twice (194%) of the one for two-hands lifting/lowering activity. It was also found that biomechanical stress by one-hand lowering/lifting activity with the half workload of two-hands lowering/lifting activity was greater than that of the two-hands lowering/lifting activity. Therefore, it might be a risk to consider the RWL of one-hand lowering/lifting activity to simply be a half of the RWL of two-hands lowering/lifting activity recommended by NIOSH.

• Journal of the Ergonomics Society of Korea
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• v.29 no.1
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• pp.145-153
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• 2010

Activity of lifting has been a major issue in many research area related in manual materials handling tasks. However, the opposite activity of lifting, lowering, has received much less attention. It is known that 52% of all box-handling tasks were lowering in nature. The difference in stress between lifting and lowering activity is not well understood. A simple assumption that these two activities are very similar has been established and widely used. However, this simple assumption may be questionable. The objective of this study was to compare a lifting activity and a lowering activity based on the three different ergonomic approaches; (1) biomechanical, (2) physiological, (3) psychophysical approach. It was found that the stress of lowering activity was from 65% to 93%, from 87% to 97%, and from 87% to 96% according to the biomechanical, physiological, and psychophysical point of view, respectively. It is concluded from the result of this study that the stress of lowering activity is lower than that of the lifting activity. The maximum compressive force on the lumbro-sacral joint (L5/S1) was 158% and 108% respectively, for lifting and lowering activity of which the work load is the 58% of Action Limit. It is suggested that the NIOSH AL and RWL and biomechanical criteria should be reconsidered especially for the low frequency of lifting activities.

• Journal of Sericultural and Entomological Science
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• v.39 no.1
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• pp.79-85
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• 1997

Bombyx mori, silkworm powder has been studied for blood-glucose lowering activity by National Sericulture & Entomology Research Institute(NSERI) and Kyung Hee University group in 1995. To obtain the optimum preparative condition of silkworm powder for lowering blood-glucose levels in postprandial time, blood-glucose lowering activity of mulberry & silkworm varieties were examined. In mulberry varieties, Samkwangjam showed the highest activity. Activity for lowering blood-glucose levels of autumn rearing silkworm was higher than that of spring silkworm and hybrid silkworm showed higher activity than that of parent silkworm. In the silkworm lines, Chinese lines showed higher activity than that of Japanese lines. In experiments to see the difference in blood-glucose lowering activity between either male and female or larvae and pupae, activity of larvae was higher than that of pupae and the male was higher than female. The heating dry and artificial diet showed lower than mulberry diet and normal freeze dry of the 5th instar 3rd day. Among the sericultural products, larvae showed the highest activity.

• Physical Therapy Korea
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• v.5 no.1
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• pp.30-43
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• 1998

The purposes of this study were to examine the effect of two different pelvic alignments and the Valsalva maneuver on electromyographic (EMG) activity of the erector spinae during squat lifting and lowering, and to find an efficient method for squat lifting and lowering. Twenty hea1thy men in their twenties lifted and lowered loads using four different methods: 1) anterior pelvic tilt position with the Valsalva maneuver, 2) anterior pelvic tilt position without the Valsalva maneuver, 3) posterior pelvic tilt with the Valsalva maneuver, 4) posterior pelvic tilt without the Valsalva maneuver. The EMG activity of erector spinae was recorded during both lifting and lowering with each method. The EMG activity of each individual was normalized to EMG activity produced by muscle during maximal voluntary contraction. Two-way analysis of variance for repeated measures ($2{\times}2$) was used to analyze the effect of the two factors: 1) pelvic tilt position (anterior pelvic tilt, posterior pelvic tilt), 2) the Valsalva maneuver (with and without). Analysis was performed separately for the lifting and lowering. The results were as follows: 1) EMG activity of erector spinae was greater when the pelvis was tilted anteriorly than when the pelvis was tilted posteriorly during squat lifting and squat lowering. 2) There was no difference between EMG activity of erector spinae with the Valsalva maneuver and EMG activity of erector spinae without the Valsalva maneuver during squat lifting and squat lowering. These results suggest that the greater EMG activity of erector spinae with an anterior pelvic tilt position during squat lifting and squat lowering may ensure optimal muscular support for the spine while handling loads, but the Valsalva maneuver may have less effect on erector spinae.

• Journal of The Korean Society of Integrative Medicine
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• v.5 no.2
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• pp.25-32
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• 2017

Purpose : The purpose of this study was to determine the effect of ribcage stabilization using a belt in the supine position during double leg lowering (DLL) by investigating the electromyographic (EMG) activities of the abdominal muscles. Methods : Twenty-two subjects with lumbar extension syndrome were recruited. EMG activity was recorded from rectus abdominalis (RA) and internal oblique abdominalis (IO), external oblique abdominalis (EO) muscles while subjects performed three double leg lowering exercises: double leg lowering (DLL), double leg lowering with abdominal draw-in maneuver (DLL-ADIM), and double leg lowering with ribcage stabilization using a belt (DLL-belt). RA, IO, and EO EMG activity were analyzed via one-way repeated-measures analysis of variance (ANOVA). Bonferroni correction was performed where significant differences were identified (p<.017, .05/3). Results : RA, IO, and EO EMG activity differed significantly among the three exercises (p<.05). The use of post hoc pair-wise comparison with Bonferroni correction showed that RA muscle activity significantly differed among the three exercises (p<.017), and IO muscle activity in the DLL exercise was significantly decreased compared to the DLL-ADIM and DLL-belt exercises (p<.017). There was no significant difference between IO muscle activity for DLL-ADIM and DLL-belt exercises (p>.017). EO muscle activity in the DLL-belt exercise was significantly increased compared to both DLL and DLL-ADIM exercises (p<.017), but there was no significant difference between EO muscle activity for DLL and DLL-ADIM exercises (p>.017). Conclusion : DLL-belt is a more effective exercise for activating the abdominal muscles than DLL-ADIM exercise. Therefore, we recommend DLL-belt exercises for strengthening the abdominal muscles.

• 대한임상약리학회:학술대회논문집
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• 2003.06a
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• pp.20-20
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• 2003

• Journal of the Ergonomics Society of Korea
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• v.25 no.2
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• pp.197-204
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• 2006

The purpose of this study was to investigate the relationship between the cumulative fatigue of trunk muscles and the period of recovery time during repetitive lifting and lowering task with two different frequencies(4 times/min and 6 times/ min). Eight healthy males with no prior history of LBD(low back disorders) volunteered for this study. Subjects had 2, 3, 4, and 5 minutes recovery time respectively while they were preforming the lifting and lowering task at 15% level of MVC. EMG signals from six trunk muscles were collected and the fatigue level was analyzed quantitatively. In results, the fatigue levels of LES(left elector spinae), RLD(right lattissimus dorsi), LLD(left lattissimus dorsi), RRA(right rectus abdominis) and LRA(left rectus abdominis) were recovered when 3 minutes recovery time was given at 4 times/min frequency. However, the fatgue level of RES(right elector spinae) was recovered when 4 minutes recovery was given. On the other hand, when 6 times/min frequency was used, the RLD, LLD, RRA and LRA were recovered at 5 minutes of recovery time. But for RES and LES, it took longer than 5 minutes to be recovered. This results can be applied to design the adequate length of recovery time to control the cumulative fatigue of trunk muscles in industry with repetitive lifting and lowering task.

• Bulletin of the Korean Mathematical Society
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• v.40 no.4
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• pp.699-701
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• 2003

This minipaper offers a formula which is dual to that of Viskov [5]. While Viskov's can be thought of as a rising formula for Laguerre polynomials, ours is precisely the lowering one. Besides documenting the formula, which seems to be missing, we want to provide a (rather elementary) operator theory argument instead of making crude calculations. In other words, the annihilation and creation operators are confronted with lowering and rising formulae; they are often failed to be distinguished.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.907-910
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• 2008

The effect of channel length reduction on the electrical characteristics of self-aligned polysilicon TFTs has been investigated by combining experimental characteristics and 2-D numerical simulations. The role of drain induced barrier lowering and floating body effects has been carefully analized using numerical simulations.