Many models of Nike football/soccer boots have a lace cover. It the laces need replacing, how do you access the eyelets under the cover to insert the new lace?
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Assuming that you've got the laces out:
Thread a piece of fishing line through the eyelets of the boot as if lacing a boot. As the line does not have the thickness of an aglet you can insert your fingers under the cover, even for the lowest eyelets.
Turn the plastic aglet on one end of the new laces so the crease, where the wrapped plastic ends, is on the side and poke the needle through the aglet approximately 1/8 inch below the end of the aglet.
Tie a knot in the line so it does not pull through the aglet.
Pull the line through the lacing eyelets in the direction of the end of line not attached to the lace, pulling the lace through all the eyelets.