A novel pulley-vest model enables progressive resistance exercise in rats without tail loading

Resistance training in rodent models is widely used to investigate muscular and cardiovascular adaptations. Traditional models often attach loads to the tail. The present study aimed to develop and validate a resistance training model for rats using a pulley system combined with a load-bearing vest, allowing progressive overload without tail attachment. Spontaneously hypertensive rats were assigned to control (CTR, n = 4) or resistance training (RT, n = 6) groups for a 10-week ladder climbing protocol. Functional and morphometric adaptations were evaluated in the soleus and flexor hallucis longus (FHL) muscles. Resistance training resulted in a significant increase in relative maximum load carried (p = 0.0007), corresponding to a 79.5% improvement in strength capacity. The RT group also showed increased relative mass of the FHL muscle (p = 0.002). Gene expression analyses did not show statistically significant differences between groups (p > 0.05). The pulley-vest system proved to be a viable and effective resistance training model for rats, allowing controlled overload while avoiding tail load attachment and potential vascular interference. This model represents a refined experimental approach for resistance training studies in rodent models, particularly in conditions where tail circulation must be preserved.