Abstract - This study created an
ergonomically designed double basket shopping cart with a purpose of reducing
Work-Related Musculoskeletal Disorders (WMSD) risks to grocery shoppers and
clerks. This study proved that the present design of the double basket shopping
cart provides pain and discomfort to the grocery shoppers and clerks which can
lead to WMSD. It also showed that incorporating ergonomic features on the
proposed design of the double basket shopping cart reduce the pain and
discomfort to the grocery shoppers and clerks. The study was conducted in
Rey-Sal Grocery Store in Cabuyao, Laguna. Code Shoppy Rapid Entire Body Assessment (REBA),
NIOSH, Nordic Questionnaire, and surveys were used to determine the pain and
discomfort that the grocery shoppers and clerks feel. Statistical Package for
the Social Sciences (SPSS) was used to help in the regression analysis of the
researchers. Anthropometry was used in the designing the proposed design, to
develop the optimal dimensions of the double basket shopping cart for the
comfort of the users.
The proposed design of the double basket shopping cart
effectively reduced the pain level and the discomfort of the grocery shoppers
and clerks. It eliminates the need for lifting motions of the grocery shoppers
due to the new design. The methods that were used were essential in reducing
the risk of WMSD to grocery shoppers and clerks. Cost-benefit analysis and
Failure Mode and Effect Analysis were also executed to evaluate the proposed
double basket shopping cart design financially, its reliability, durability and
performance. Keywords - Ergonomics, double basket shopping cart, work-related
musculoskeletal disorder, grocery store.
METHODOLOGY
In order to fulfill the objectives of the study, a pre-test
and post-test study has been conducted as a requirement. The study required two
types of respondents: grocery clerks and grocery shoppers.
Sample size was computed with the use of Slovin’s formula, error tolerance was
set to 10%. The sample size was used for gathering surveys, REBA, NIOSH, Nordic
Questionnaire, and anthropometric measurements which are needed to assess the
current design of the double basket shopping cart. Rapid Entire Body Assessment
(REBA) was used in order to determine the risk level of the specific activities
done by the grocery clerks and grocery shoppers while using the present design
of the double basket shopping cart. NIOSH lifting equation was used to assess
the lifting motions done by the grocery shoppers and to compute for the maximum
load that can be lifted during the shopping process. While the Nordic
questionnaire was used to assesses the pain that the respondent feels on
different parts of their body. The pre-test also included conducting of
pre-test surveys and gathering of anthropometric measurements of the
respondents.
Anthropometry was used in establishing the optimal dimensions of
the proposed double basket shopping cart, 5th, 50th,
and 95thpercentiles
were considered. The obtained preliminary data was used and analyzed through
the use of Statistical Package for the Socials and Sciences (SPSS). The
software was a primary tool to test the normality of the anthropometric data
and to determine the correlation between two distinct variables.
The
correlation of the gathered data was determined with the use of four tests:
Binomial Logistic Regression of one dependent and five independent variables,
Spearman’s Rho Coefficient of nominal and scale data, Kendall’s Tau Correlation
of nominal and ordinal data, and Phi Coefficient of two nominal data. Binomial
Logistic Regression was used to test whether the body parts of the grocery
shoppers and clerks can be affected by the characteristics of the double basket
shopping cart which are, comfortability, handle height, wheel design,
maneuverability, and the height of the base of the double basket shopping cart.
Spearman’s Rho Coefficient was used to correlate the pain felt by the
respondents with their age, weight of goods they buy, and height. Kendall’s Tau
Correlation of nominal and ordinal data was used to correlate the pain felt by
the respondents with the characteristics of the double basket shopping cart.
Phi Coefficient of two nominal data was used to correlate the pain felt by the
respondents with their gender. The post study used the same number of sample
size and same set of clerks were assessed for the post study.
The post study
includes the post survey, post REBA, post Nordic Questionnaire, which tested
the usage of the proposed double basket shopping cart during the shopping
process, stacking process and nesting process. The post study did not require
another NIOSH lifting equation due to the proposed design that eliminated the
need for lifting motions. The weighted mean average was also used to determine
the significant change with the respondents regarding the present and proposed
design. A cost-benefit analysis was used to compare the monetary values of the
present and proposed design with the non-monetary benefits that each design
gives. The Failure Mode and Effects Analysis were used to assess the potential
failures in using the proposed double basket shopping as well as what risk
should be prioritized.
