The LIFTMOR randomized controlled trial found that 8 months of supervised high-intensity resistance and impact training (HiRIT)—involving heavy lifts like deadlifts and squats at 80–85% of 1RM plus jumps—significantly improved bone mineral density (BMD) at the lumbar spine (+2.9%) and femoral neck (+0.3%) in postmenopausal women with osteopenia or osteoporosis, compared to declines in a low-intensity control group (-1.2% and -1.9%, respectively). The HiRIT group also gained 44% in back extensor strength, improved functional mobility (faster timed up-and-go), and increased stature (+0.4 cm), with no fractures or serious injuries, demonstrating that properly supervised heavy lifting is safe and more effective than traditional light exercise for reducing fracture risk in this population.