but any means known in the art to adjust the liquid level of the center portion 10 b may be utilized both a leg extension leg curl attachment 45 and a fly machine attachment 50 comprise expandable bladders 27 a liquid tank system 25 a 25 b having at least one tank supplies liquid solution to the bladders 27 the liquid solution travels from the tank 25 a 25 b through a channel 28 to the appropriate attachment 45 50 or other attachment such as a bench press or other type of weight machine the weight resistance is manually set by dials 30 a 30 b on respective tanks 25 a 25 b however a computer operated system may alternatively be utilized with the present liquid weight system a dial adjustment 22 allows for adjustment to the length of the cables 28 to accommodate variation among users the foregoing is considered as illustrative only numerous modifications and changes will readily occur by those skilled in the art the present teachings are not desired to limit the invention to the exact construction shown and described and accordingly all suitable modifications and equivalents that fall within a scope of the invention may be resorted to for example the expandable bladder discs.