With　the　change　of　modern　lifestyle,　the　number　of　people　living　a　sedentary　life　is　increasing,　which　can　lead　to　sustained　tension　in　the　low　back　muscles,　which　in　turn　can　cause　lumbar　muscle　strain　and　even　low　back　pain.　Measuring　low　back　muscle　fatigue　in　real　time　could　help　prevent　and　rehabilitate　low　back　pain　and　improve　the　health　of　sedentary　individuals.　In　this　paper　we　aim　to　estimate　muscle　fatigue　of　low　back　muscles　in　vivo　using　electrical　impedance　myography　(EIM).　EIM　measurements　were　performed　using　a　proprietary　impedance　measuring　device　and　the　commercial　ImpTMSFB7　human　body　composition　analyzer.　Impedances　measured　with　both　devices　showed　correlation　greater　than　0.99　and　a　linear　decreasing　trend　with　duration　of　fatigue　contraction.　The　impedance　of　the　lumbar　muscles　measured　at　the　end　of　the　experiment　when　fatigue　occurred　(240　s)　was　16±2　Ω　lower　than　the　impedance　measured　at　the　beginning　of　the　experiment　(0　s).　The　measured　resistance　decreased　by　approximately　13　%　and　the　reactance　increased　by　approximately　8.5　%　during　low　back　muscle　contraction,　indicating　a　sufficient　sensitivity　of　the　muscle　impedance　graph　in　detecting　low　back　muscle　fatigue.　These　results　contribute　to　the　research　of　EIM　assessment　of　low　back　muscle　fatigue　and　provide　valuable　guidance　for　additional　research.　©　2023　IEEE.