ABSTRACT
This study examined the variation in individuals' static maximum forward pushing and backward pulling (FPBP) strength for handleless cartons under different task conditions. Thirty young Taiwanese men were recruited as participants and were requested to perform maximum FPBP exertion tests under four exertion heights (50, 80, 110, and 140 cm), two types of hand contact (bare hands and gloves), and two carton widths (40 and 60 cm). The results of this study indicated that the pushing strength for handleless cartons was almost twice the pulling strength for all exertion heights. This finding is different from those of previous relevant studies. The pulling force generated when gloves were worn was 38% higher than that generated under barehanded pulling. Moreover, the pulling force generated with a 40-cm-wide carton was 13% higher than that generated with a 60-cm-wide carton. Pushing strength was affected by only the exertion height. Practitioner Summary: We examined the effects of exertion height, carton width, and type of contact on the maximum FPBP strengths. Pulling strength should be considered first for the related task design because it is lower than pushing strength. However, pulling strength can be maximised by wearing gloves to pull a 60-cm-wide carton. Abbreviations: FPBP: forward pushing and backward pulling; ANOVA: analysis of varianceHIGHLIGHTSMaximum forward pushing and backward pulling (FPBP) forces vary for cartons.FPBP forces for force direction, contact type, carton width, and exertion height were examined.FPBP forces generated for handleless cartons differ from those generated for cartons with handles.Pulling strength can be maximised by wearing gloves and using a 60-cm-wide carton.Gloves are useful tools for pulling handleless cartons.
Subject(s)
Hand , Biomechanical Phenomena , Humans , MaleABSTRACT
The objective of this study was to psychophysically determine the maximum acceptable weight of lift (MAWL) for polypropylene (PP) laminated bags. Twelve men were requested to decide their MAWLs under various task combinations involving 3 lifting ranges, 3 lifting frequencies, and 2 hand conditions. The results revealed that the MAWL was significantly affected by the frequency and range variables (all p<.001), whereas the hand condition did not influence the MAWL. The participants exhibited relatively low MAWL values compared with subjects in previous studies, especially in infrequent lifts. The results of multiple stepwise regression revealed that certain anthropometric data (e.g., chest circumference, wrist circumference, and acromial height) accounted for the percentage of variance for the determined MAWLs, ranging from 56.2% to 83.4%. These data can be obtained simply and quickly, and are considered the superior predictors for MAWL determination when handling PP laminated bags.
