Working Posture and the Center of Mass Assessment While Starting a Chainsaw: A Case Study among Forestry Workers in Croatia
Round 1
Reviewer 1 Report
Dear Authors,
I have finished my review on your paper. Indeed, it is important for forest operations to have in-depth research on all the relevant topics, out of which safety plays an important role. I have read the manuscript with much interest. The first point I would raise is that of better documenting the introduction by adding the latest papers on the motor-manual work. There are some published at least in the last 10 years, of which some are focused of ergonomics and safety. Double-checking the terminology used, redundancy in phrasing and English phrasing won't hurt for a better prepared paper (e.g. workers working, relief, unenviably). In particular, lines 44-45 need some supporting citations. Lines 69-79 (as agreed by the Authors in discussion) need some references to point the reader to all the tasks in motor-manual work so as to be able to made a fair judgement on how much would it take to start the chainsaw. There are many papers reporting on time structure-time consumption which could probably help here. I would exclude the methods used from goal and objectives, focusing them only on the comparisons made, as explained in more general words. Line 145: why, and how was selected just one image per subject? Reading some other papers on similar topics, they used several images in a sample to overcome the variability...Lines 183-191: are there any references or some plausible criteria for framing these categories? Discussion is quite well written, however I've missed the implications of the results, scalability and an in-depth explanation of the mechanisms behind the obtained results. Conclusion should not contain references and it should be shortened. Reference list seems to be balanced, but it would benefit from adding more studies here, particularly to better document the introduction and to improve the discussion.
Congrats and good luck!
R.
Author Response
We thank to referee 1 for positive contributions. We have corrected and renewed our manuscript according to reviewer’s comments. These corrections or answers to inquiry are given below:
AUTHOR’S REPLAY TO COMMENTS OF REFEREE 1
Comment 1 - Better documenting the introduction by adding the latest papers on the motor-manual work!!!
Answer: We appreciate the comment! The latest papers are included in the Introductory part → „In the last decade, numerous authors investigated the issue of motor-manual work regarding the current ergonomic condition of chainsaws in non-professional use [5], workload, exposure to noise, and risk of musculoskeletal disorder in poplar clear cuts [6] and time consumption and productivity in manual tree felling with a chainsaw [7].”
Comment 2 - Redundancy in phrasing and English phrasing won't hurt for a better prepared paper (e.g. workers working, relief, unenviably).
Answer: We appreciate the comment! The above was changed in the paper!
Comment 3 - In particular, lines 44-45 need some supporting citations.
Answer: in the originally submitted version of the paper, the text in lines 44-45 contains supporting citations. Therefore, additional citations are not included in the paper!
Comment 4 - Lines 69-79 (as agreed by the Authors in discussion) need some references to point the reader to all the tasks in motor-manual work so as to be able to made a fair judgement on how much would it take to start the chainsaw.
Answer: Unfortunately, the studied papers of the last ten years nowhere within the technological structure of time highlight chainsaw ignition as an individually measurable element, i.e. we did not find information on how much the chainsaw ignition element is represented in percentage compared to other elements in felling time consumption! Therefore, additional references are not included in the paper.
Comment 5 - why, and how was selected just one image per subject? Reading some other papers on similar topics, they used several images in a sample to overcome the variability.
Answer: For the REBA method one image per subject was used because it represents the position in which the worker visually deviates the most from the natural N-pose. For CoM all the data from the beginning to the end of the work element were analyzed.
Comment 6 - Lines 183-191: are there any references or some plausible criteria for framing these categories? Discussion is quite well written, however I've missed the implications of the results, scalability and an in-depth explanation of the mechanisms behind the obtained results.
Answer: Unfortunately, there are no references for framing subject criteria! Regarding in-depth explanation, a new paragraph is included in the discussion → “A higher deviation of the worker from his neutral N-pose is resulting in higher obtained points in individual body segments and consequently higher risk of MSDs. To firmly secure a dangerous tool, workers must abandon the N-pose while doing it, and that's why the safe chainsaw starting methods are being evaluated with higher points per segment. While immediate safety in motor-manual felling and processing is a primary objective, it comes at a cost of awkward postures and possible future injuries.”
Comment 7 - Conclusion should not contain references and it should be shortened.
Answer: The part related to the references in the conclusions was changed! Considering that reviewer two had no objections to the length of the conclusions, the subject suggestion was not accepted by the author!
Comment 8 - Reference list seems to be balanced, but it would benefit from adding more studies here, particularly to better document the introduction and to improve the discussion.
Answer: We appreciate the comment! The latest papers are included in the Introductory part (see the changes in comment 1)!
Reviewer 2 Report
In fact I found some small issues: - incorrect numbering of tables in the text, - page 3 - L125 - 132 not clear if only one worker vas measured, - small pictures, - and maybe it would be fine to explain the vertical deviation (for example fig 4 and 5). Do the higher values mean lower health problems?
Author Response
Thank you for your input. The answers are as follows.
- Table numbers in the text have been corrected
- Lines 125-132 are describing a sampling procedure, it is clear that a number of workers have been selected for two measurements, later in the text it is visible that 74 workers were assessed by REBA, and 28 workers participated in the kinematic study.
- Figures are of good quality and can be (are) enlarged.
- An additional explanation is added regarding Figures 4 and 5 in the Discussion
- All corrections are visible in the updated manuscript
Reviewer 3 Report
Manuscript ID: forests-2218720
Type of manuscript: Article
Title: Working posture and the Center of Mass assessment while starting a chainsaw: A case study among forestry workers in Croatia
Authors: Matija Landekić, Marin Bačić *, Matija Bakarić, Mario Šporčić, Zdravko Pandur
Dear authors
The manuscript entitled " Working posture and the Center of Mass assessment while starting a chainsaw: A case study among forestry workers in Croatia " has studied the impact of three different chainsaw starting methods (from the ground, between the knees and “drop start”) on the postural load of the chainsaw worker and its association to personal and occupational factors with trunk posture assessment by the Rapid Entire Body Assessment tool and for the Center of Mass measurement by the Xsens MVN Link motion capture suit. Statistical analyses have done. Results showed that mean REBA score for all three methods is between 4 and 7, placing all methods at a medium level of MSD risk. Authors concluded that the safest A method of starting a chainsaw from the ground is also the riskiest in terms of postural strain, but based on REBA score and CoM vertical deviation, C method which is considered unsafe resulted with the least postural strain.
Generally, the quality of manuscript is well written and suitable. The subject of the research work is original and has been able to provide a lot of new information in the field of working posture and the Center of Mass assessment for working with chainsaw. The authors were able to answer the research questions due to the review of suitable sources, the study method of the region and the sufficient number of samples, and there is no need for additional items in the method and also other controls. The authors were able to match the research conclusions well with the evidence and arguments presented and address the main question raised. References were well presented and good previous researches were listed, however, some related references proposed that should be mentioned in the manuscript. Tables and figures are well organized and logically consistent with the content of the text.
The study design is robust and the topic fits well to the scope of the journal. The manuscript is generally clearly designed, written and illustrated. The discussion of the manuscript also well written.
Best regards
Comments for author File: 
Comments.pdf
Author Response
We thank referee 2 for positive contributions. We have corrected and renewed our manuscript according to reviewer’s comments. These corrections or answers to inquiry are given below:
AUTHOR’S REPLAY TO COMMENTS OF REFEREE 2
Comment 1 - There is no proportionality between abstract parts. The abstract section should be rewritten. The results should be mentioned quantitatively.
Answer: The above has been corrected in the paper. A paragraph related to the results is included in the abstract of the work “Results showed that there is a significant difference between the three starting methods in the REBA score, as well as in the number of segments scored during the assessment. Obtained mean REBA score for all three methods is between 4 and 7, placing all methods at a medium level of MSDs risk. Regarding the analysis of the Musculoskeletal disorders vertical deviation the statistical difference is noticeable for the body mass index (BMI) group, group related to experience at the chainsaw, age and height group in relation to three methods for starting a chainsaw.”
Comment 2 - Was the chainsaw model the same in all three cases?
Answer: The brand of the chainsaw was the same (Stihl), but the model of the chainsaw differed from respondent to respondent. An explanation is included in the materials and methods chapter!
Comment 3 - According to the result, which work posture can be applied by chainsaw man at the start time?
Answer: An explanation is included at the end of conclusion chapter (see reply to comment 6)!
Comment 4 - Why did you choose the starting part among the different elements of working with a chainsaw? How important is this element compared to other work elements?
Answer: Starting a chainsaw element was chosen because there are 3 different ignition methods for the same purpose, which allows for a relevant comparison. With other working elements, there is one or at most two ways to do the same (where there are significant changes in the position of body segments). The elements of tree felling from the postural aspect and participation in the technological structure of time are much more significant and will be the subject of analysis and processing in the next paper!
Comment 5 - Please be specify about the model and etc...
Answer: an explanation for the brand and model of the chainsaw is included in Materials and Methods → “All sampled workers used the Stihl brand of chainsaw, while the model of the chainsaw differed from respondent to respondent (MS 661 in 25%, MS 461 in 21%, MS 462 in 47% and MS 500i in 7% of cases).”
Comment 6 - According to the results, which method of starting have high safety and low risk for MSD that can be proposed for chainsaw worker?
Answer: Final remark is included at the end of conclusion chapter → “In conclusion, from the safety and postural aspect, “between the knees” method is the most optimal for use when starting a chainsaw in professional forestry.”
