There’s some debate on the topic of plantar fasciitis, running, and bone spurs. If running caused bone spurs then more people who run long distances would have bone spurs. And some people who don’t run at all get bone spurs so running isn’t the only cause of bone spurs.
There is a delicate balance between the bones in your feet and the ligaments, tendons, and nerves. Aging and postural components may be a part of the problem, too. People over 40 and especially women seem prone to plantar fasciitis and bone spurs. Running style and run down shoes may be risk factors for anyone prone to plantar fasciitis.
Tight soft tissues along the bottom of the foot causing friction and irritation to the bone from running may contribute to the problem. Heel spurs related to plantar fasciitis occur after calcium deposits build up on the underside of the heel bone. Heel spurs can take months to form. A proper warm-up with stretching of the plantar fascia (band of tissue on the bottom of the foot) may help prevent these problems.