2.3. Methods
Torque measurements were taken for each subject with the
three packages using two gripping techniques: bidigital and tridigital
(Fig. 4). Subjects were instructed to hold the packaging at the
height of the abdomen and turn the cap with their maximum
strength. The sequence of packages and gripping techniques were
randomized with online software (www.random.org). A single
torque measurement was taken for each packaging and gripping
technique; therefore each subject performed a total of six trials,
with one minute rest interval between the trials.
Prior to data collection, volunteers read and signed an informed
consent form that had been approved by the Ethics Committee of
Faculty of Science (Process n. 254.413/2013). In the case of the
children, the Consentwas obtained from their parents or guardians.
2.4. Data analysis
The average (and standard deviation) torque was obtained for
each group of subjects in each of the six situations (two gripping
techniques and three packagings). The condition of normality
(Shapiro Wilk's W test) and homogeneity (Levene's test) of data
were verified. In order to compare the average torque among the
groups, ANOVA test was applied to normal and homogeneous data
to compare both devices. Non-parametric tests were applied
(Friedman, Kruskal-Wallis, Mann-Whittney or Wilcoxon) to the
data sets that did not meet these conditions. All results were
considered significant at a P value of 0.05 or less.
3. Results
The results for the average maximum torque for the three
packages and two gripping techniques among all groups are summarized
in Fig. 5. Grip technique was shown to be a key factor
influencing torque transmission when opening CRPs. For all the
subjects groups, maximum torque was significantly greater with
tridigital prehension than bidigital for all the packages.
Overall, the transmitted torques of children (3e5 years) were
lower than all other groups when opening the three packagings,
taking each prehension technique separately. Furthermore, the
maximum torque measurements of the elderly group were lower
when compared to adults (30e59 years), with significant difference
found only for the packaging with cylindrical cap.
Considering the cap design, the greater maximum torques were
found in the packaging with inverted conical cap for all groups and
both gripping techniques, with significant differences when
compared to the packaging with conical cap. When it comes to
gripping technique, the tridigital torque measurements for the
packaging with conical cap were the lowest values for all groups.
Possibly the main finding of this study is that the torque
transmission with tridigital grip for children under 5 years old (the
risk group for accidental poisoning) was higher when compared to
the bidigital grip for all groups and packages.