A weight training system comprising: a barbell comprising: a first end portion (202, 204); a second end portion (202, 204); and a middle portion (206; 206a, 206b) couplable to the first end portion and the second end portion, the middle portion comprising: a male coupling extending from a first end of the middle portion, the male coupling providing a first coupling mechanism that engages with a corresponding female coupling of the first end portion, and a female coupling providing a second coupling mechanism that engages with a corresponding male coupling of the second end portion; and two or more exercise weights, characterized in that each exercise weight comprises: a flexible weight holder having a plurality of chambers, the chambers arranged along a length of the weight holder and oriented transverse to the length of the weight holder, and each chamber having a closure device for securing one or more weights within each chamber, the flexible weight holder being configured to be wrapped around the first end portion or the second end portion, one or more straps attached to a first end of the weight holder, the first end being transverse to the length of the weight holder, and one or more strap fastening devices attached at a second end of the weight holder, the second end being transverse to the length of the weight holder, wherein the weight holder is rolled into a cylinder shape when each of the straps are fastened to corresponding ones of the strap fastening devices. a barbell comprising: a first end portion (202, 204); a second end portion (202, 204); and a middle portion (206; 206a, 206b) couplable to the first end portion and the second end portion, the middle portion comprising: a male coupling extending from a first end of the middle portion, the male coupling providing a first coupling mechanism that engages with a corresponding female coupling of the first end portion, and a female coupling providing a second coupling mechanism that engages with a corresponding male coupling of the second end portion; and a first end portion (202, 204); a second end portion (202, 204); and a middle portion (206; 206a, 206b) couplable to the first end portion and the second end portion, the middle portion comprising: a male coupling extending from a first end of the middle portion, the male coupling providing a first coupling mechanism that engages with a corresponding female coupling of the first end portion, and a female coupling providing a second coupling mechanism that engages with a corresponding male coupling of the second end portion; and a male coupling extending from a first end of the middle portion, the male coupling providing a first coupling mechanism that engages with a corresponding female coupling of the first end portion, and a female coupling providing a second coupling mechanism that engages with a corresponding male coupling of the second end portion; and two or more exercise weights, characterized in that each exercise weight comprises: a flexible weight holder having a plurality of chambers, the chambers arranged along a length of the weight holder and oriented transverse to the length of the weight holder, and each chamber having a closure device for securing one or more weights within each chamber, the flexible weight holder being configured to be wrapped around the first end portion or the second end portion, one or more straps attached to a first end of the weight holder, the first end being transverse to the length of the weight holder, and one or more strap fastening devices attached at a second end of the weight holder, the second end being transverse to the length of the weight holder, wherein the weight holder is rolled into a cylinder shape when each of the straps are fastened to corresponding ones of the strap fastening devices. a flexible weight holder having a plurality of chambers, the chambers arranged along a length of the weight holder and oriented transverse to the length of the weight holder, and each chamber having a closure device for securing one or more weights within each chamber, the flexible weight holder being configured to be wrapped around the first end portion or the second end portion, one or more straps attached to a first end of the weight holder, the first end being transverse to the length of the weight holder, and one or more strap fastening devices attached at a second end of the weight holder, the second end being transverse to the length of the weight holder, wherein the weight holder is rolled into a cylinder shape when each of the straps are fastened to corresponding ones of the strap fastening devices.