We developed a novel heavy PoWeR model (hPoWeR) utilizing higher wheel loads (max of 12.5 g vs 6 g). Adult male C57BL/6 mice voluntarily performed an 8-week progressive loading protocol (PoWeR or hPoWeR). At the end of the protocol, in situ contractile function determined strength of the posterior plantarflexor muscles; then harvested muscles were assessed for muscle mass, muscle fibre cross-sectional area, fibre type and anabolic signalling. A summary of results for each intervention is provided. In conclusion, these data suggest hPoWeR modestly induces skeletal muscle alterations that better reflect typical resistance training adaptations, in line with decreased running volume and exposure to higher resistance. Figure generated using BioRender.com.