In addition to the various benefits of rucking, it also has some harmful effects on your body, especially if you ruck improperly. As we know excess of everything is bad, overrunning may thicken tissues of the heart, causing fibrosis. Moreover, if you're not comfortable with your backpack, you may cause nerve compression injuries. However, if you go for appropriate weight, proper posture, and a comfortable backpack (shoulder straps), rucking can never be bad for you.