A bar grip used for grasping a bar or similarly shaped object for physical fitness such as a weightlifting bar, barbell, pull-up bar, or rowing paddle that requires significant grip force. A determination is made of biometric data from a user equipment having an associated user. The therapeutic molecule can comprise any molecule capable of being conjugated to Vpr or a fragment thereof, including a polypeptide, a polynucleotide, andor a toxin. The retainer is locked at the full locking position by the resilient engagement of full locking claws with full locking sections as well as by the fitting engagement of elongated locking projections formed on the inner surfaces of the leg pieces with end portions of the guide grooves.