“…17,26,27,37 Reported results in all four showed an increase in IAP, but electromyogram in the erector spinae muscles consistently decreased in only one. 27 In seven studies, investigators measured IAP but did not simultaneously record an electromyogram of the back muscles (Table 3), 15,16,24,43,42,52,62 Investigators in two of these studies reported an increase in IAP in subjects using lumbar supports, 16,52 in two studies they reported inconsistent results, 15,43 and three they found no effect of a lumbar support on IAP. 24,42,62 Separate meta-analyses for studies on electromyogram of erector spinae muscles and on IAP were conducted.…”