Invented by Dr. Carmelo Bosco while he was researching cures for muscle atrophy in astronauts due to Zero G. This technique basically involves wearing weights. "Gravity Doping" is what at least one Ph.D. calls Hypergravity Training, which is used by people ranging from mountain climbers at 50 lbs. to firefighters and special forces at up to 100 lbs. and astronauts at 2.5 G. The aerobic advantages are believed to be great, but are usually brought up in the context of "2.5 G". That means if you weigh 150 lbs., wear 225 lbs. or build a gravity cycle.