Although it appears to be a conceit within some sci-fi novels as well as films...employing liquid or gel to suspend your body will do NOTHING to help protect you from excessive g-loads. Your internal organs, circulatory system, connective tissues, etc. will all experience the extra g's, which will kill you slowly (at extended low g's) or very, very quickly (at high g's). Air Force G-suits use air pressure to constrict lower extremities of a pilot's body in order to try to keep the blood from draining from the brain. Even so, modern G-suits only play a minor part in preventing "G-LOC"...with the greater contribution coming from the pilot's physical training, and specifically the "G-Strain" technique. Nevertheless, accelerations of 6-9 g's can only be sustained physically for a matter of seconds.
What would make sense, from a technical/scientific standpoint, would be using a liquid gel to prevent pressure ulcers (bed sores) forming in crew members who are in suspended animation. By the way, bed sores (if untreated) will ultimately lead to infection, tissue necrosis and eventually death. The only real solution in preventing such conditions in humans who would be immobile for long durations, would be complete immersion AND suspension in a liquid, in order to achieve a floating, neutral buoyancy.
