There are several requirements for being very fast, or better yet for being “on time.” Key technical requirements are mastery of the movement and relaxation, or more accurately, lack of needless tension.
There is an obvious connection with conditioning here because both mastering the movement and relaxation are developed by repeating the move in great numbers and that depends on being in good shape.
Also, the greater your muscular endurance the more relaxed your muscles are so the less tired they get. Yes, people in poor shape tense more and so get tired sooner.
The key mental requirements are an unwavering concentration on the opponent, lack of hesitation, and no doubts about your capability.
These mental requirements are also connected with conditioning. Countless correct repetitions develop skills to the point of totally reliable habits and automatize your reactions, thus preventing doubts and anxiety. Long repetitions also teach maintaining concentration on the task while under pressure. Being in poor shape and struggling with the body diverts attention and undermines confidence. By the way, you can learn the right type of concentration for fighting from the Gold Medal Mental Workout for Combat Sports. It is not enough to concentrate hard. You have to know what to concentrate on and how to focus your concentration—narrowly or widely. The hypnotic suggestions on the GMMW audiotapes will give you that knowledge and much more.
Your conscious mind interferes by deliberately planning moves if you are anxious or unsure what to do. Right drills give you competence, which in turn gives you the confidence to “let go” and trust your instincts. Right drills make you react to opportunities without hesitation so you are “on time”—which is better than just moving fast.
Look at a good boxer fight—his punches are fluid, his whole body is relaxed no matter how fast he moves. This is the result of drilling—of hundreds of days (at least) of well-designed drills. No matter what type of techniques you use you can display the same relaxation and focus with right drills. Well-designed and well-selected drills make techniques smooth, fast, and on-time by stripping them of useless movements and of unnecessary tension. They make the techniques habitual, without need for conscious decisions, and impart confidence in their effectiveness so you do not hesitate and thus act fast.
Learn the steps for learning and then mastering techniques and how to tie technical training with conditioning from the book Science of Sports Training: How to Plan and Control Training for Peak Performance.
Article by Thomas Kurz, co-author of Basic Instincts of Self-Defense and author of Science of Sports Training, Stretching Scientifically, and Flexibility Express.