The paper "Effectiveness of the multidimensional ergonomic intervention (MEI) model to reduce musculoskeletal discomfort among street sweepers in Chiang Rai province, Thailand" is a clinical trial (as reported a "quasi-experimental study". The sample size was not randomly recruited, and there is no description about a clinical trial registration (https://clinicaltrials.gov/). Also, the primary/secondary outcomes were not established. I recommended that in future studies CONSORT guideline should be followed.
The English need extensive revision, and the poor methodology compromises the findings of this study.
Introduction
Page 3, last paragraph: The authors reported that "The aim of this study was to evaluate the effectiveness of multidimensional ergonomic intervention (MEI) to reduce MSD among street sweepers in the Chiang Rai municipality." However, the authors failed to precisely determine the primary outcome of this clinical trial. In this way, what is the primary outcome? Pain intensity? Number or frequency of complaints of MSD? What is the hypothesis of this study?
Methods
Please, clarify, was the sample size calculated? How?
Please, clarify this statement: " were scored at level ≥ 4 by physiotherapist"?
Were the instruments used translated and validate into The Thai language?
Please, describe precisely what intervention was administered to the control group. It is not clear.
The statistical analyses are not adequate (it is not a repeated measures ANOVA analyses).
Results
There are a lot of tables, without any description of mean values and 95% CI. What is the "strength score"? How is it calculated? What is "discomfort score"? How is it calculated? Is it validated? What is the minimal important difference of this measure?
Discussion
The limitations of the study (characteristics of design or methodology) have impacted or influenced the interpretation of the findings. In this way, it is not possible to make any conclusion considering the flaws during the study conducting.