You can not have an enchanted item that just gives you +5 to athletics or something like that. But there are a number of ways you can still get what you want:
Maneuver Spell:
You can create an enchanted item that has a maneuver spell stored in it, so when you use the item, it creates the aspect "like the wind" on your character, and then you tag that aspect for +2 on an athletics roll. It should be an aspect that is appropriate to the task at hand.
Skill Replacement Spell:
Instead of creating an aspect, you can let the spell do all the work. So you make an enchanted item with a stored effect and don't use your skill at all. For example, you make jumping boots with a 5 shift effect, and when you want to jump from rooftop to rooftop, which is a difficulty of 5. Your athletics is 3, so you think you probably won't make it on your own, so you activate the boots, and the 5 shift effect from the boots is enough to get over the 5 shift chasm. If you'd needed 6 shifts, the boots would be useless, since they don't have enough power.
Item of Power:
This is the big one. If your character concept is built around a wizard that boosts his speed with magical items, you might want to do it big. Instead of enchanted items, you buy the "inhuman speed" power with refresh and add the "Item of Power" limitation to it. From the story point of view, that's just like any of his enchanted items, he's just able to use it a lot more often than others. It's only the mechanics that are changed.
