Abstract: A method of treating volumetric muscle loss (VML) injury involving the administration of a hydrogel that is free of biological cells and growth factors is described. The hydrogel can comprise a crosslinked hydrogel matrix further comprising heparin wherein the hydrogel can be administered to a subject in precursor form and allowed to crosslink in situ in a muscle injury site or administered in a lyophilized powder, sheet or disc form. The presently disclosed subject matter further describes lyophilized hydrogel matrix materials, such as sheets, wafers and powders, that can be used to treat VML injury.