As part of our jobs many of us read literature that few others see. For example, every two months I get a journal called Industrial Health, published (in English) by the National Institute of Occupational Safety and Health of Japan. It's been around for a long time (it is now in Volume 46) and it's pretty good. It frequently has papers that are interesting and the December 2007 issue (which just arrived in my mailbox) is an example. One article is entitled, "Biomechanical and physiological analyses of a luggage-pulling task," by Jung, Haight and Hallbeck. It's about those two-wheeled suitcases you see everyone pulling when you travel on an airplane. This an occupational health subject because flight crews use them:
It can be easily observed that pulling luggage causes awkward postures of a lateral trunk bending and an asymmetric arm extension. Potential risk factors from such a posture need to be further studied and ergonomic luggage design criteria to be recommended for reducing physical workload on such users. (Industrial Health,v. 45, p. 756)
Yes, there are people who study such things. In this case they got four male volunteers to pull a luggage prototype, 56 cm high by 26 cm long by 46 cm wide with a handle height of either 1 meter or 1.1 meters. The handle could be rotated zero to 90 degrees and the pole angle either straight up from the suitcase or bent slightly 10 degrees. Two diameters of hard rubber wheels (8 cm and 15 cm) were tested. Forces were measured in six different directions as the subject was videotaped while pulling this thing on a treadmill. A bunch of markers were placed at various points on the body so twisting, bending and other motions could be tracked frame by frame. Energy expenditure was measured using heart rate and oxygen uptake. Every subject performed 32 3 minute trials over two days while camcorders captured luggage-pulling motion, the load transducer collected pulling forces and oxygen and heart rate measured.
And that was just for starters:
Manual digitized 3D marker coordinates were converted to 3D coordinates about the global reference system by using the formulas of Martin and Pongratz [cite omitted]. The second order Butterworth filter in Eq. (1), a recursive digital filter processing raw data in the time domain [cite omitted], was applied forwardly and backwardly with a 5 Hz cutoff frequency to reduce the noise and phase distortion of the coordinates.
[snip]
The kinematics of a whole body with the right hand holding luggage was calculated as an input for a 3D inverse dynamic biomechanical model. Etc., etc.
I'll skip the detailed Results and go directly to the bottom line:
In conclusion, a luggage-pulling task mainly stresses the right arm and is classified as "light work" by the criterion of American Industrial Hygiene Association [cite omitted] because it needed only 3.2 kcal/min of metabolic energy and 99.3 bpm [beats per minute] of heart rate on average. Subject height and related walking speed is of importance to the task and heavy belongings should be placed at the bottom of luggage when packing. Large wheels are prior to handle height, pole angle and handle rotation for an ergonomic luggage design.
In other words, choose short parents, get a bag with larger wheels and pack the heavy stuff at the bottom.
Any questions?
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I hate rolling luggage, especially when used in lieu of a briefcase by people in metros, office buildings, and conference center. They're noisy and take up way too much room.
As luggage, I don't care for them. But as briefcases I HATE and DESPISE them.
Good stuff.
I wish there were an easy way to get improved prototypes into production, for luggage and any number of other poorly-designed objects. Every once in a great while, you see some fluff news story about some garage-based inventor who builds the better mousetrap with items he has McGyver'd from around the house.
In many cases, the new designs are far better than what is available, but the interest in the improved version is low. Personally, I don't know what all is entailed in getting some new invention to market, but I have some ideas, nonetheless.
Last year I had to get a breast core-needle biopsy. The Breast Center I visited was pleasant and comfortable. The procedure most definitely was not. I had to lie face-down on a table with a bucket-sized hole in it, and position my chest over said hole. My neck had to be turned at an extreme angle, one arm at my side, and I had to stay completely still for about twenty minutes, although it felt like much longer.
My neck was really in great pain, and the fact that I couldn't even micro-adjust my position to ease the stress on it was miserable. I was at the end of my rope long before the procedure was done.
I've related this story to a few women, and for the ones who have had this procedure, all have agreed it is really uncomfortable. A co-worker said she demanded that someone massage her neck muscles throughout, and my nurse did the same for me.
Why does a design like this continue being used? How hard would it be to come up with something that allows the patient a little more comfort during the biopsy? I heard one rumor that the hole-in-the-table was originally designed for prostate exams and procedures. I don't know if that is true, but it wouldn't surprise me.
In the end, I was declared A-OK, but only after another surgical biopsy to remove "Atypical cells." I confess to a suspicion that I had been moved along the procedure chain because of my decent health insurance plus maybe an overdose of caution. I have no family history of BC, and no great risk factors.
Slightly off your Occupational Health topic, revere, but Patient Ergonomics could wander into it, I think.
The rolling luggage is popular with people who have back problems. It's also a pain in the ass for everyone else--the fiddling with the handle at the jetway, the ill-sized bags that clog overhead bins, and the huge amount of space required for a person and the bag trailing behind them (which they can't see). I use luggage that also functions as a backpack. I take up less space this way and the bag is easier to fit in an overhead compartment and I burn more calories. People al;os can see the bag, somthing that often doesn't happen with the wheelies.
wenchaha: Not off topic at all (or at least on an interesting other topic). The "market" and competition are supposed to handle problems like this. They don't, obviously. Glad the outcome wasn't as difficult as getting there.
"choose short parents" doesn't work revere, my oldest sister is 6 ft. 1 in. and both her parents were short.
You must be young Rich. Consider for a moment the older folks that are traveling, rolling luggage is imperative.
Plus it's not as easy for them to move at the expected lightning speed that seems prevalent in getting down the jetway to the plane.
I love a good occupational health and safety article.
My dad was a pilot before he retired -- you want to talk asymmetrical stresses and body torsion, try lugging around one of those fully-loaded, leather-sided regulation flight bags. Ouch! I think my dad's must have weighed somewhere between 30 and 40 pounds, and had the sort of handle that only lends itself to a one-handed carrying grip.
Consider for a moment the older folks that are traveling, rolling luggage is imperative.
It isn't just older folks who need this sort of accommodation, but handicapped people too. I'm not out of my 30s yet, but because of the gait irregularities I have due to cerebral palsy, travelling with anything other than either rolling luggage or a backpack is quite likely to destabilise something in my back.
So right you are Interrobang, thanks for bringing that up.
Let me rant on for a moment too please. While traveling recently to Europe I was mildly pissed-off over the "these passengers first," Elite/Business class first, then parents with small children.
I can barely understand the elite/business because they paid more, money rules. But the parents with small children thing could stand some revamping.
Yes, before you mommies and daddies get started on me I already understand how hard it is to travel with the wee ones, but do you understand how difficult it is for an older person or handicapped or temporarily injured person too?
The airlines should adjust their "loading first" policies to these groups. I can hear it now, or would like to, elite/business customers first then, over 55 and handicapped and then parents with small children.
Lea I used to travel a great deal and I remember upon boarding they used to announce "anyone requiring assistance", after business class and small children, before us cattle car passengers. I naturally assumed they meant handicapped and elderly. But PLEASE don't get me started on travel. I hated my fellow passengers who stuck their carry-on in the first available overhead bin and then headed to the back of the plane to their assigned seat. Just plane rude (pun there)! I also hate women who dig through their purses for the exact change when making a purchase and I happen to be stuck behind them. If something costs 9.69 JUST hand the cashier a 10 dollar bill will you! I don't want to watch you count out 9 dollars and then fumble around opening your purse, then looking for your change purse or wallet with that little change pocket on the side, all the while whispering "I have the exact change" to the cashier, and then fumbling around with the change and COUNTING out loud, "oh here's a quarter, thats 25, 35, 40, oh 50, 60, 65, 66, 67,68...wait I know I have another penny somehwere"... Not that you are like that Lea, I just needed to get that off my chest.
pauls: You and I have finally come into complete agreement.
Agree with you pauls lane on everything you said. Especially the first available overhead bin deal, that pisses me off as well. The cattle car/herd mentality is so prevalent in our society.
On our trip back to the states there was an obviously physically fit gentleman fumbling through his overhead binned luggage, holding up the loading line, and I said in a voice that could be heard, "is that really necessary right now", as I pushed my husband forward past the ignorant soul. Nearly pushed the guy into the seat too!
The older generation at the same time needs to be considerate of others around them whenever possible.
I've given up on the cash transactions and it's debit cards, fast and easy.