Value of the Data •The exercise, muscle force, and neuromuscular junction morphology data provides information regarding the age-related differences between rats selectively bred for low and high response to training that may give insights into the varied trajectories of functional declines within aging populations. •The transcriptional data examines potential genes associated with aging that researchers can further investigate to determine if they contribute causally to differences between low and high responders. •These data are useful for researchers focused on aging who wish to understand further the effects that mild exercise training in old age has on weight bearing and non-weight bearing skeletal muscles in low and high responding rats.