Building muscle vs. endurance, know the difference ☝🏻 Follow @fitchicksusie for more fitness tips. One of these is building muscle, while the other is not. Heavy weight low reps = strength training aka building muscle. This type of training focuses on max force and building larger muscle. This is in the lower rep range between 6-10. Light weight high reps = muscular endurance aka training the muscle to work longer without fatigue. These have a higher rep range of 12-20. If you are wanting to bu