One way I was taught to think about reductions is as reduction of the oxidation number yea, but a more quick and dirty was is oxidation is adding oxygens (or other electronegative element) and reduction is adding hydrogens. So alkyne is more oxidized then alkene then alkane.
I suppose the way you are supposed to think about that is that hydrogen is less electronegative than hydrogen, so you break a bond to carbon and replace it with a bond to hydrogen, which works if you think about oxidation numbers as well.