Lifting Ergonomic assignment Alex Luhrs
12005958
Photographer- Laura Dobson
Task Details Cycling is a sport that provides you with a huge sense of freedom and achievement where ever you are cycling. However cycling around your local are can often become repetitive as so traveling to different ares/regions or to races are evens is key. 95% of bike owners have bike racks but in the winter salt and road grime is picked up and left on your bike by your car and those that pass you, so driving with the bike in the boot keeps your bike clean and saves you the dirty work of a intense clean. The tasks shows the process and steps involved in removing the bike frame and wheels from the boot. Then fitting the wheels without letting the frame touch the ground as that can cause damage and scuff marks on the drop-outs and rear derailleur. This whole process involves bending of the back with arms fully extended as a result amplifying the weight as the levers are longer, the good news is the frame weighs so little so one off lift it is a relatively safe thing to do. The tricky part is then getting the wheels lined up to fit in and for the skewers to be tightened, a process that can take a bit of manipulation.
Ergonomic Assesment Percentiles and Measurements Carriers Height - 1807mm Mean 50%ile - 1745mm SD- 69 1807-1745/69- 0.8985 Carrier is in the 82nd/81st percentile for height. Elbow Fingertip lenght- 480mm 480-475/21=0.2381 59th Percentile Shouder to Eblbow Length- 380mm 380-365/20= 0.75 77th/ 78th percentile. Vehicle- Volvo V70 (03)- Boot dimentions Lenght- 172cm Height-80cm Width- 140cm
Object Infomation Ribble Evo Pro Carbon Bike Total weight - 6.65kg With out Wheels- 4.25kg
Ground Conditions Fortunately over the past few weeks the weather has been very dry but cold, as a result the ground was completely dry so there is very little chance of slipping. The car is parked on a block drive which is very even but the road does drop down to the right slightly leading to a Iron drain cover and a small kerb which are both trip hazards. I was wearing Salmon Trail cross fell running shoes at the time so that further minimised the possibility of tripping or loss of grip. The possible trip and slip hazards are highlighted below.
Trip Trip
Slip
Unloading task
This first Image shows the bike frame and wheels in the boot. The frame is laid flat with the wheels leaning out away from the frame, they aren’t placed on top as this could damage the frame. The next process is removing the wheels so you can easily get to the frame.
Removing the wheels was a simple process but referring back to the MAC guide the lift weight especially with the wheels is very light but the key thing is the hand distance from the body. As you can see from the image to the right my body is nearly bent at 90 degrees with my arms out significantly increasing the load on my back. On the other hand the load weight at this point is so small there was little f any difficulty.
The two thumbnail images show the grip on the wheels which was very goo as spoke count on the wheels is low there is plenty of area to get a good grip and to be comfortable.
This shows the actual removal process and is well described by the MAC Handling assessment. It highlights that it is a dangerous lifting position giving it a score of 6. This is very accurate as you can see the position of my back and bend in my neck puts a lot of pressure on my back. My legs have to be straight as if they were bent they would catch on the rear bumper. The only redeeming feature is that the load weight is 4.25kg.
Finally out of the boot you can see the grip I have on the frame, the top tube has a nice circular profile so grip is strong and comfortable, the front fork has an aero profile but is still easy to hold on to. This current lifting position isn’t hard to maintain as elbows are roughly around 90 degrees and additionally the weight is close to my body meaning you can hold the frame comfortable. The MAC guild identifies the grip as Green which I believe is accurate.
This lift has to be maintained as you have have to put the wheels on. The grip is good and vertical lift is also very good and both are identified as green in the MAC assessment, this is down to it being around hip height and close to my body. The only two difficulties are the balance of the frame you have hold it further back near the seat tube to make wheel fitting easier and also Trunk twisting is identified as Amber which is accurate as your body has to twist to reach round to get the wheels.
Fitting the front wheel is tricky but is made harder if your skewers are too tight meaning it cannot if into the fork, also you need to ensure the wheel is in straight so it doesn’t catch on the brakes. At this point I have to use one arm to hold the frame, its weight is 4.25 kg and using the MAC it was identified as green and safe to repeat but I think that this should be modified as you are doing it single handed whist trying to fit wheels.
Fitting the rear is even trickier than fitting the front but now the weight is taken by the front wheel as you fitted it earlier. At this point body can be relatively straight with little if any weight bearing being done by the arms.
This final step of fitting the wheels requires you yo push the rear Mech down allowing the wheels to drop in, check the wheel is straight to stop it fouling on the brakes. The only danger here is the posture constants as you are bending down whilst holding the bike still.
Now that all the wheels are in check that the skewers are tight and the wheels spin freely, there is no weight load but twisting of the trunk occurs as you rotate and swop from front to rear. The MAC assessment is accurate here as there is no weight is involved buy still involves rotation of the trunk.
Often when the rear wheel is inserted you end up in the wrong gear, take this opportunity to spin the cranks to change gear. MAC assessment identifies this is safe but I believe the excessive bend in the back and lifting of the rear wheel could lead it to back strains and problems if it is repeated regular.
Now that everything is finished and fitted correctly take a moment to check your brakes and your ready to ride.
APPENDIX Calculating percentiles: Xp=M+Z(S) Xp is the desired dimension for percentile p. M is the mean value of the dimension. Z is the Zscore (+/-) obtained from normal distribution fro percentile desired. S is the standard deviation of the dimension. Example: Stature 1807mm-1745mm/69 81st/82nd percentile
Z value = 0.8985
REFERENCES & BIBLIOGRAPHY Pheasant ST (1986) Bodysapce Taylor & Francis: London Health and Safety Executive (2004) Manual Handling - Guidance on Regulations (L23) (3rd edition - revised post MAC) London: Health and Safety Executive HSE Manual Handling at Work (2013) HSE Manual Handling at Work A Brief Guide [online] Available at http://www.hse.gov.uk/pubns/indg143. pdf [Accessed: 10 April].