Since I've been here, back when I was a member not an analyst, I've noticed that many call something that is 'strong' whatever that means, also 'impulsive'.
To the Elliotician this is not the same. Impulsive is a statmement of structure and has nothing to do with 'strength'. In fact, I love a slow-mo impulse, as it gives me an edge that is unique. For example if a stock is working on a slow impulse and corrects back in wave 2, it will often produce mis-priced options as implied volatility is about to explode but due to slow price action it is not priced in.
So, here is what I call a 'reliable impulse'.
1. 5 waves
2. Each of the subwaves are 5 waves except 2 and 4
3. Third wave is properly extended to the 1.382 at a minimum
4. the 4th does not cross the 1st wave.
It's a high bar to call something impulsive.
Note 1,2,and 4 are HARD RULES all Ellioticians share. 3. Is particular to Avi's work, and what I call needed for reliability though I may in some situations let it pass. But rarely.
There are many 'strong' three waves moves.