If one is to be a good competition coach for a single student, one task that is important to become competent at is to watch your student´s opponents in early matches, and from those observations put together a game plan for your student.
I was thinking on how to do that in the best way, and it suddenly struck me that there is one aspect of the opponent that is critical to what sort of game plan one should put together, and is also something that I have not heard other coaches mention.
That does not seem to be a word previously written in English, so let me explain: If fencer A can perform a set of pre-planned activities that are intended to trigger a specific and predicted activity by fencer B, and that triggered response is highly repeatable (provided that the triggering activities are done well) then fencer B is highly triggerable, or has a high triggerability.
It is not necessarily so that triggerability is a generalized trait for a fencer, it can very well be so that a fencer is highly triggerable for one set of triggering activities but considerably less so to another. How much this trait is generalized as a person-specific trait, and how much it is a situation-specific trait, is something that I do not know, but I think would be very useful if it were known.
What can a coach do with the information that a specific opponent has a high triggerability? Simple. In that case, a big part of the game plan to defeat that specific opponent is to perform the triggering activities (and do that well!), be prepared for the expected reaction from the opponent, and then perform the offensive action that has the expected reaction as a sufficient prerequisite.
An example: Let us say that you, as a coach, has seen that the opponent to your student has shown a specific triggerability: he will, if correctly triggered, attempt to score by doing a coupé to the upper surface of the lower arm of the weapon arm. (This is of course epeé.) You have also figured out what the triggering actions are. In that case, a big part of your game plan for your student would be to perform the triggerings, and when the opponent is winding up the coupé, prepare to move the lower part of the weapon arm up and to the lateral side. Once the coupé is going down, execute that minor movement. Then the coupé will fail, and the blade of the opponent will be caught in the upper-lateral corner of the bell, contacting both the bell and the blade of your student´s weapon. In essence, the opponent has then put himself in a position where your student has successfully parried sixte. From there, the obvious action for your student is to do an immediate riposte in sixte while in opposition.
Rinse&repeat. If the opponent has some other reliably triggerable action, then modify as necessary.
The power of this approach is that a lot of people have a lot of difficulty with modifying their reactions quickly, especially if those reactions are defensive and ingrained.
On the other hand: if you as a coach find that your student loses matches due to the fact that his opponents have exploited his triggerability, then that is something that you must work on during training sessions.
Considerations for other weapons: So far, I have have considered this in an epee context. When I think about it, this should be even more important in sabre, since the short timespans give opponents less time to consider what they are doing wrong, and and also forces sabre fencers to rely on trained reflexes. As for foil: I will leave that to coaches with foil experience.
Important limitation: It is probably not a good use of coach observation time to search for triggerabilities in top-level fencers. If a fencer reaches high levels of competitions, then it stands to reason that he does not have any easily exploited triggerabilites – i he had, his opponents would have used them to beat him before he reached to later DE stages. Therefore, triggerability searching is probably something that a coach should focus on when both the studied opponent, and the student, are of low to intermediate experience level.
Should the coach see that an opponent does not have any obvious triggerabilites, then he should go back to the drawing board and design a game plan where the offensive part is based on whatever other weaknesses the opponent exhibits.
Opportunity for game plan testing: Imagine this very specific case: coach A has two students B and C, in a poule. Student B is head and shoulders above the competition in the poule, and can be reliably expected to win against the rest of the fencers in the poule even if he does not fence to his outmost. There is also a specific opponent D in that poule. Assume here that fencers C and D are reasonably well matched, so that coaching can be what tips the balance in favor of C. Assume further that the B-D matchup comes before C-D. If all those prerequisites hold (the stars will not align like that often!) then coach A can feed a tentative game plan to B, and observe the results. A should tell B to only follow that game plan until one can see whether it works or not, and once that is done, finish D off with his superior overall ability. Given the observations from the B-D match, the coach can then affirm, refine, revise, or discard the triggerability part of the game plan, and give a better game plan for fencer C.