Hi Mr Wood,
With great respect to Khan boxing skill, speed, and agility, I doubt with glove he can punch blow the eight candles because:
Assume if the punch is at the angle in line with candles, then speed of the wind seems too fast for the punch speed.
That is the last candle went off bit too early. This raises my suspicion.
I actually suspect it is more difficult with glove, because the speed is decreased with increased weight, and also there is something else than the speed needed the gloves will decrease. And the air displaced perhaps not as focused. On this, I could be wrong.
The purpose of this training without gloves is not only with speed, but with angle and depth of displacement in tissue. You need the right angle (pun intended) and focused force (with great efficiency) to deliver this effect.
If not, it will be like wobble sword in cutting, the force is not focused and damage the goods.
So even if the opponent is retreating and contacting tissue is soft like the touching thin air, the force still go through.
Not sure about with gloves though, perhaps the objective is the same.