ization . ▁Other ▁comp lications ▁that ▁arise ▁from ▁imm obil ization ▁include ▁mus cle ▁at ro phy ▁and ▁o ste op or osis , ▁especially ▁to ▁the ▁lower ▁lim bs , ▁increasing ▁the ▁risk ▁of ▁f ract ures ▁to ▁the ▁fem ur ▁and ▁tib ia . ▁While ▁pass ive ▁weight ▁bearing ▁of ▁par al yz ed ▁lower ▁extrem ities ▁appears ▁to ▁be ▁in effect ive , ▁stress ing ▁the ▁b ones ▁through ▁mus cular ▁contra ctions ▁initi ated ▁by ▁functional ▁elect rical ▁stim ulation ▁( F ES ) ▁has ▁yield ed ▁positive ▁results ▁in ▁some ▁cases . ▁The ▁intensity , ▁frequency , ▁and ▁duration ▁of ▁stress ▁to ▁the ▁b ones ▁appear ▁to ▁be ▁important ▁determin ants ▁of ▁improved ▁b one ▁parameters . ▁Gener ally , ▁the ▁frequency ▁is ▁effective ▁with ▁three ▁or ▁more ▁week ly ▁exercise ▁sessions . ▁Studies ▁of ▁duration ▁suggest ▁that ▁several ▁months ▁to ▁one ▁or ▁more ▁years ▁of ▁F ES ▁are ▁necessary . ▁ ▁Im pro ving ▁locomot or ▁function ▁ ▁Im prov ement ▁of ▁locomot or ▁function ▁is ▁one ▁of ▁the ▁primary ▁goals ▁for ▁people ▁with ▁a ▁sp inal ▁cord ▁injury . ▁S CI ▁treat ments ▁may ▁focus ▁on ▁specific ▁goals ▁such ▁as ▁to ▁restore ▁walking ▁or ▁lo com otion ▁to ▁an ▁optimal ▁level ▁for ▁the ▁individual . ▁The ▁most ▁effective ▁way ▁to ▁restore ▁lo com otion ▁is ▁by ▁complete ▁repair , ▁but ▁techniques ▁are ▁not ▁yet ▁developed ▁for ▁reg ener ation . ▁T read mill ▁training , ▁over ▁ground training , ▁and ▁functional ▁elect rical ▁stim ulation ▁can