National Sports was started by a man named Norm Clements in 1968 selling sporting goods from the trunk of his car under the name National Gym Clothing Ltd. in and around the area of Stouffville, Ontario. Better known in the world of horse racing, harness racing to be specific, was the proud co-owner of 1982 Horse of the Year Cam Fella who won 28 of his starts that year. In the picture below Norm is on the far left, Cam is the horse of course, trainer-jockey Pat Crowe to the right of the horse and co-owner Norm Faulkner on the far right. The picture is from the Nov.19, 1982 Toronto Star (and is available for a low as $175 from Getty images).
Eventually he was able to open some brick & mortar stores (one in Aurora, Ontario and another in North York, Ontario). National Gym was the "cool" place to get your hockey equipment in the late 70's - early 80s. It wasn't cheap but they had everything. If you wanted a pair of LA KIngs ugly purple & gold socks they had them. For any NHL team both home and away versions. One year I picked up a blue JOFA hockey stick to match my teams sweater colour. I didn't even know Jofa made hockey sticks until my dad took me to the store! I grew up in a town named Newmarket which is just north of Aurora, and about 5 miles west of Stouffville, but that stick was bought at the North York location which was much larger and had way more selection.
What does all this have to do with your card? Well he was a bit of a swindler and schemer also. He took one of his old barns and some of the property to open a weekend market in his home town (Stouffville Flea Market). At the time there was a law banning stores from opening on Sundays in Canada (at least in the province of Ontario). He didn't care too much for the law, and every Sunday the local York Regional Police show up would fine him. I am guessing he made lots of money from these, and the fine was just the price of doing business for him?
Not sure when National Gym became National Sports exactly but by the late 1980's for sure. Which would fit in and around the time of this card. There is a big card show here in Toronto (world's largest hockey card show for sure) in a few weeks. If I happen to see these or remember I'll ask some of the older vendors/dealers. I've been going to this show since the very first one back in May of 1991, with the exception of the Covid years and the first live show they did post Covid, and know a few of the vendors from both this and the odd local show I've attended. So if you don't mind waiting another 3 weeks or so (unless someone else comes forward in the between time) I may be able to at least let you know if this was some kind of promo from National Sports the store(s).
"They've done studies, you know. Sixty percent of the time it works every time." - Brian Fantana from the movie Anchorman