We have designed two HIIT swimming protocols for elderly rats. During the pilot we found that the rats are not able to perform the protocols based on the percentage of their body weight because their body weight is high (450 - 550 gr) and as a result the percentage of their body weight is high. I thought of determing their maximum strength by using an incremental valid protocol and determining their exercise intensity based on their maximum strength (weight carried at the final stage of incremental test). What do you think?