As an initial proposition for thought, I suggest that instability creates the potential for having to stop or correct a situation or action before you can effectively take an action that will result in a successful outcome. On the other hand, controlled instability is clearly necessary for success in attacks. The following key areas may create instability on the strip:
Motion. When both fencers are moving at the same speed in the same distance, the condition is essentially stable. Variations from this in speed, distance, the mechanics of movement, and especially timing all create instability in favor of one or other of the fencers. Attacking when the opponent has one foot up in motion closing the distance (the opponent’s negative instability) or from the front foot on your marching step when an opening appears (your positive instability) are examples.
Body position. Changes in body position impact balance, create openings where there were none before, and introduce inefficiencies of movement. Out of balance with an unrealized opening and unable to move quickly to deal with the opponent’s attack, counterattack, or riposte is a highly vulnerable state.
Movement of the blade. The stable blade can move as fast as the fencer’s reaction time, movement time, and physical conditioning permit. The blade in motion has to be stopped and then redirected at a cost in time and in disruption of the fencer’s ongoing tactical actions.
The plan. It seems obvious that a fencer should enter the bout with a plan, and then constantly modify and refine that plan based on the performance of both the fencer and the opponent. Continuing to follow a plan that no longer addresses the conditions of the bout creates instability in that the fencer’s tactical actions do not coincide with the changing situation.
The fencer’s psychological state. Frustration, negative thoughts and self-talk, focusing on negative external factors, and even excessive excitation all erode the positive mental state required for high performance. They can drive poor decision-making and hesitant performance, and have the tendency to be increasingly self-reinforcing in a negative way, leading to increasingly bad outcomes.
As a fencer your goal may be to introduce as much instability as possible in the opponent’s game. Similarly your goal may be to reduce instability in your own. Not all instability is bad – successful attacks always are unstable. Not all stability is good – a static fencer who does not move when under attack is merely a target. The key is to find the right balance, use stability when to your advantage (for example, in not reacting to obvious feints), and instability when it is appropriate.