There are some papers on this topic and running. I don't know that I've seenone on lifting.

I do not find any reason that similar females "would have to carry objects further from the body". This would overload the lumbar spine. No matter if the breast size is large or small, they should lift and carry objects close to the body (under the breast). This trick shortens the anterior lever arm, makes lifting more effective and less harmful to the spine. On the other hand, females with large or plasically enlarged breast have serious problems with the thoracic spine - overloading, kyphotic posture, structural kyphosis, back pain.

If carrying something at waist height against the abdomen with the elbows bent at 90 degrees, it would seem to me that abdominal girth rather than chest size s the concern as this will increase the distance the object is positioned from the spine.  So your question may be about females, but may also indirectly be answered in males.  If a man has significant body fat, we would expect him to have larger abdominal girth.  

So here is a question.  What is the increased distance from the abdomen to the spine when one is carrying a load, between a thin adult and an obese adult?  How does increased abodiminal girth affect forces in the lower back when carrying a standard weight of 50 lbs or less?  Spine researchers should have some answers on this, as they will have measured the distance between the load handles and the spine in different populations.

I don't know how this would relate to breast size, except to say if an obese man has significant body fat, as evidenced by larger breast fat, we may predict he will have increased risk of back pain, due to the longer distance a load must be carried in front of the spine, because he will also have increased abdominal girth. 

Dear Karen,

Breast size may affect the range of motion in the direction of the breast. Meanwhile, breast size affect running efficiency but this has been solved by sport bras. If we consider breast size is obstacle to carry things close to the body then moment arm would increase and consequently the moment will be greater on the lumbar vertebrae. We, I think need to question whether this is a real problem or not. If the size of breast causes a real problem in lifting then we could analyze the lifting and infer the conclusion.

Carrying a weight in front is not advisable, it is not advised for men also. It will be painful. Ergonomically not proper.

I have not studied the problem but have a solution for the problem. In Indian villages, women carry heavy weights, up to 30 kgs, on their back (packed in a basket or sack or bag) or on their head. If it is a pot full of water, then, they carry the weight on their head or hip.

Dr.S.Ravindran

Thanks everyone.  I conclude that no actual science exists on this. I think this would be an excellent project for a student, since it is unlikely that North American employers, at least, will stop asking workers to carry big heavy boxes in front of them.

Dear Karen 

I agree with you.  This is good question for graduate student to be investigated. 

It could be hypothesized that women with larger breast size would change the COG and LOG anteriorly compare to women's with normal breast size or male population. The changes in COG & LOG may increased loading in back and hamstring muscles which may leads to alter efficiency of lifting.

Another point may be larger contour may leads to inefficient grasping or anchoring the objects...

Joking and begging pardon if obscene, in Spain we say "tiran más dos tetas que dos carretas", no possible translate.

Vicente, this is a good proverb. I got the meaning by the Google translator.

Regards

Sigh! I guess it was just a matter of time before the guys started making jokes about this, with no consideration for women with work-related backache.  Probably explains  the paucity of real science.  

Dear Karen

You have asked a real disadvantage stage of women worker. Yes if breast size is disproportionate among the women then load will be a few cm away from cg thus a chance is there.but most load at shop floor is handled at waist height not at breast height thus women do not have any real scientific problem rather habitual practice. if you handle; load at breast height it will be automatically disadvantage due to other bio mechanical points. though clear scientific study is rare it is reality women are allowed to work in all such situation with out any problem. pcg,Chennai

Thanks Paresh for your thoughtful answer.  I don't know how it works in your country but here women are often in health care and child care where they often handle human bodies which are not confined to waist height.  And even boxes held at waist height means the bottom of the box may be at waist height or lower but the top of the box is often at breast or shoulder height.  See the pictures in this report:  http://www.irsst.qc.ca/media/documents/PubIRSST/R-808.pdf p. 30 for example or even p. 55.

Dear Karen

I like the article. 

Why not use a small cart like device.  When the staff lift heavy box like materials, let them sit down - hold the bottom of the box - and stand up along with the box.  

I have suggested on this matter before also.  

Carrying a weight in front is not advisable, it is not advised for men also. It will be painful. Ergonomically not proper. 

Dr.S.Ravindran

Dear Dr Karen

Thank you for your reply. I have seen your IRSST report of Canadian institute. do correct some times it is above waist height is disadvantageous to women as well as men not because of breast size but bio mechanical point only. which can be corrected. . pcg,Chennai

I have not seen any research currently connected to this issue. Because improper lifting resulting in injury can be traced to so many different aspects, it could be difficult to find a definitive link, but I believe that a connection could potentially exist. I have seen breast size as a connection to back problems (most often these women will opt for breast reductions in order to re-establish the proper spinal curvatures).

I think that this is a topic that would be difficult to make a direct connection, but could serve as a factor in the tidal wave of biomechanical alterations that result in lifting injuries. 

However, This type of research might also result in women being shunned from the work force due to "yet another disadvantage of the female doing the male's job." We live in a society that has not yet blossomed from the manure left behind from past sexual discrimination. I think that this research would be EXTREMELY pertinent in reducing/preventing injury in women performing manual labor, but as always, someone will manage to twist the truth and use it in their own social agenda. Be ready for a potential fight. 

 I wish you the very best of luck with this project and look forward to what you find! 

Yes I do agree with myor her view is considerate.let us leave together some disadvantage of this nature man can help women so peaceful co existence is best. Beside pursue some research to really understand it is problem or not. pcg Chennai