Just read down a little further but impeding means stepping into the path of someone. There may be contact as he runs into you but that would still be obstruction. They also explain a bit about dangerous play. Raising your foot would be dangerous but it becomes a foul when contact is made, at...
http://www.fifa.com/mm/document/footballdevelopment/refereeing/02/79/92/44/laws.of.the.game.2016.2017_neutral.pdf
See page 82
ps. I hope you're not a ref!!!!