Reaction and its speed are tremendously important in fencing. Speed of reaction is, in fact, significantly more important than speed of movement–an action done at a “medium” speed that starts very early will still be very successful, whereas an incredibly fast movement done too late will still fail.
An incredibly important thing to consider when developing speed of reaction is, obviously, the ability to recognize the stimulus. What is often neglected, however, is the idea of timing in the reaction.
A stimulus for a reaction is not simply a signal to start a movement, it’s a window of time during which the movement may be executed. In fencing, that window is always very small.
Very often a fencer may be working with a partner or coach, looking to develop reactions, but completely ignoring the timing limits created by the reaction “window”. A coach may, for example, say, “When I attempt to engage your blade in four, execute acceleration lunge with disengage and hit to high-inside line.” This exercise is fine ONLY if the student is looking to hit during the reaction “window”.
How do we define the beginning and end of a reaction window? In fencing, the opportunity to react is defined by the movement of the opponent. The window opens as the opponent begins his movement (actually, sometimes slightly before) and finishes the moment his movement ends.
In the case of the coach searching in four: as soon as the coach’s blade finishes its search, the moment to hit is lost. Attempting to hit any later affords the opponent (coach) the opportunity to make a second blade action and parry. (This is, in fact, something the coach should occasionally do to confirm that the hit is arriving on time and to demonstrate the concept of timing to the student.)
When dealing with beginners, the coach should simply make his stimulus slower (though just as realistic in quality), thereby increasing the window.
It is the ability to react during the window of a stimulus that makes a fencer seem “fast” and it is a major component of taking an opponent by surprise and becoming a superior fencer.