One of the neatest training aids for a fencer is a simple quarter! Here are two great uses I know...do you have others? (For our European readers, any coin about 1.5-2cm in diameter and fairly thin, will do).
The twenty-five cent lunge lesson
Back in the 70s, I studies with a venerable old German fencing master. His style of fence was certainly early 20th century, and may even have been older than that. I don't know what his age was when I studied with him, but he did mention his first exposure to fencing occurred before World War I. Suffice to say he was old, and yet with a sword in hand, he moved like lightening! In fact, I remember his lunges striking the target like rifleshots! Despite his power, and the fact he wore heavy looking old leather shoes and not sneakers., his lunges were very quiet. "Zee lunge shouldt be qviet, like A kat!" he would tell us.
Several years later, at college, I was exposed to a training tool that taught that kind of cat-like speed and fierceness, while training us to lunge in a way that was safe for our knees, too.
The tool was a simple quarter.
But first, lets take a quick look at the lunge. On of the most common mistakes a beginning fencer makes is to execute the lunge by stepping forward into it, as if it were a static pose one moves into. Now, an effective lunge covers the distance of two steps in the time of one, so obviously, it has to be faster than a single advance step to be effective, otherwise, two advance steps would do fine. The second mistake you often see, even by high-level fencers, is to launch the lunge forcefully off the back foot (which is fine) but ignore the front leg. As such, the lunge causes the fencer's body to "fly" up and they come down hard on their front leg, which is usually fairly relaxed in that moment, and unprepared of the kind of shock it will receive on landing. This kind of flying lunge can eventually wreak havoc on the sensitive knee joint of the front leg.
In fact, a good and safe lunge employs both legs, not just the rear leg. After extending the weapon-arm, a wise fencer kicks forward the front leg, and thrusts forward from the rear-leg (classical fencers launch off the rear heel, competitive fencers like to use the ball of the rear foot). The front leg forward-kick begins a fraction of a second before launching off the rear leg, so that , at end of the lunge, the forward momentum of the body neutralized by a rolling motion of the front foot, similar an ordinary heel-toe step (land on the heel not the toe! Only a ballaestra lands on the toes, and that's a hop!)
Done right, no matter how powerful a lunge is, it lands fairly quietly. Like a cat.
So a good finish to the lunge depends on how prepared the front foot is. In order to function effectively, the front leg has to kick forward to be ahead of the lunging body.
To train this, simply put a quarter under the heel of the front foot when you practice your lunge (if wearing rounded-heel sneakers, you may want to put the coin under the ball of the heel). Now practice your lunge: extend your arm as you normally do, kick forward your lead leg while thrusting off the rear leg. The forward kick should propel the coin straight forward ahead of you.
If you've fallen into the bad habit of lifting your body during the lunge, the quarter won't move, and you'll step over it. However, if you kick spontaneously while lunging, and without raising your body it'll work brilliantly (hint--relax the rest of your body! There may even be a feeling of your body dropping slightly during the lunge).
You might also notice that this exercise prevents you from "flying" which is to say, your body, and so your sword, will move in a straight line towards your intended target, and with more force, rather than upwards. You become more powerful, more direct and more accurate.
If you've been experiencing front-knee trouble, give this exercise a try--you may be very relieved!
Safer hand parries
If you practice an historical style like rapier or smallsword you know it's important to keep the thumb and fingers tightly together. It's good form, and in actual practice, helps keep your fingers from getting tangled up with your opponent's blade when things get messy. In an actual encounter with sharp weapons, this could keep you from having your thumb or finger cut off!
When you practice, try holding a quarter sandwiched between your thumb and hand. It'll remind you to keep those fingers together!