The increase in leg press 1-RM in the 138 % group ( 20 4 % ) was significantly greater ( P < 0.05 ) than the 0 % ( 8 3 % ) , 33 % ( 8 5 % ) and 66 % ( 8 4 % ) groups , but not the 100 % group ( 13 6 % ; P = 0.15 ) .