Belte r r a Cor p or at ion S afety M an ual D oc I D C H S M BE L 2 0 1 7 Pa g e 3 35 of 53 8 Doc u m e n t Identif icat ion S W P 012 P age Nu m b e r 9 OF 14 Doc u m e n t C r e ation Dat e F e bru a r y 02 2016 Im p le m e n tat ion Dat e Ma rc h 16 2016 the he ig ht of th e wor k a c c ordin g to bod y dim e n sions using e lbow he i ght a s a g uid e Diff e re nt tasks re quire diff e re nt wo rk sur f a c e he ig hts P re c isi on wor k suc h a s wr it ing or e lec tronic a sse mbl y 5 c m abov e e lbow he ig ht e lbow support is ne e de d L i g ht wor k su c h a s a sse mbl y li ne or me c ha nic a l j obs a bout 5 10 c m bel ow e lbow he i g ht He a v y wo rk de mandin g downw a rd f o rc e s fr om 20 40 c m below e lbow h e ig ht To pe rf orm a n y c ontroll e d moveme nt wit h the a r m m usc les in t he shoul de r a nd the n e c k ti g hten a nd st a y ti g htene d fo r a s lon g a s t he task r e quir e s The ti g h tene d mus c les sque e z e th e blood vesse ls whi c h r e stricts t he flow of blood a ll the w a y down to the w o rkin g muscle s of the ha nd How e ve r this i s whe re t he blood i s ne e de d the m ost bec a use of the intense muscula r e f for t Tw o thi ng s ha pp e n a s a r e sult The ne c ksho ulder muscle s be c ome ov e rtire d e ve n thou g h ther e is l it tl e or no moveme nt At t he sa me t im e the r e duc e d blood s uppl y to t he re st of th e a r m ac c e l e ra tes fa ti g ue in t he muscle s that a re movi n g makin g them more pron e to i njur y