This protocol describes a non-randomized pilot study aimed at examining the effects of a 16-week progressive multimodal resistance training program on bone mineral density in older women with osteopenia. The intervention is based on the systematic manipulation of muscle action type and joint range of motion as the primary prescription variables, integrating multi-joint machine-based exercises and functional exercises oriented toward activities of daily living. The protocol details the study design, participant selection criteria, intervention and control procedures, outcome assessment using dual-energy X-ray absorptiometry (DXA), ethical considerations, trial registration, and the statistical analysis plan. The results of this pilot study are intended to generate preliminary evidence and to inform the methodological design of a future large-scale randomized controlled trial.