This topic came up at a recent conference and no concensus was reached. The question is;

Does the same MET expendature for pushing or pulling x30' (or carrying for that matter) occur as when lifting from floor to knuckle or knuckle to shoulder or shoulder to overhead? :roll:

If not (which is my gut feeling), shouldn't we reconsider the estimated job demands (resistances) for pushing/pulling when using the DOT, since the DOT's ratings are based upon MET expendatures? For example; If the position as Material Handler in a wharehouse falls in the Heavy category (heaviest occasional lifting is 100 lbs.), wouldn't/couldn't our estimated push/pull requirements be more like 30-50 lbs. of horizontal resistance occasionally pushed (Medium?) vs. up to 100 lbs. (Heavy) by default by the Workstation?

It has been my experience that good effort subjects can usually lift more "resistance" than push/pull a resistance x 30', when the limitations with testing are biomechanical endpoint or exceeding max HR-lending to the opinion that there is a significant difference in MET expendature. The sequence of testing may skew these results somewhat (fatigue as testing continutes) but I honestly think it is "harder" to push/pull 50 lbs. of resistnace x 30' than lift 50 lbs. Granted, the morbidly obese client will probably have opposite results, but that opens up only more questions in my mind regarding the MET expendature "classification" for pushing/pulling. Typically, I don't use classifications for work based upon someones pushing and pulling abilities, as I feel uncomfortable stating that someones ability to push 45 lbs. of horizontal resistance equates to the Medium demand level of work.

This may seem somewhat trivial, especially when we only consider Occasional testing, but what about when we consider using classifications for Frequent or Constant-based upon Leonard's 1993 table? Pushing/pulling 25 lbs. of horizontal resistance frequently would only be Medium work. Try it for 66% of an hour.

The other camp speculated that force x distance is work, and MET's, and therefore it does not matter if you are pushing/pulling/lifting-50 lbs. is 50 lbs. (Get that right, Brandon?).

Of course, empirical measurements are preferred for workplace pushing and pulling comparisons, but often this is not possible and is not always applicable. Does anyone else have an opionion or know of research on this theory? Do "norm" ratings from Snook testing for these values provide any useful insight? Thanks!!