In a method for reducing the impact of a force upon a person seated in a safety seat of a motor vehicle at least a seat unit of the safety seat is restrained at least in part by at least one support strap. The support strap is formed with an extension piece configured to lengthen when exposed to a load as a result of an accident or explosion. A winding unit holds the support strap to shorten an effective length of the support strap and to build up a force to maintain the support strap under tension after the support strap underwent a lengthening in an area of the extension piece as a result of a load caused by a force resulting from an accident or explosion so as to reestablish an effective length of the support strap for lengthening during a subsequent force impact.