Criticisms of patterns
On the negative side, not everyone is enamored with patterns. Some think patterns are a complete waste of time. They think the repetitive movements of patterns do nothing to improve muscle memory, but in fact, repetitiveness is what builds muscle memory. Some think patterns do not improve timing since there is no resistance to techniques and there is no impact. However, the crucial hand-foot timing that is required for maximum power is improved. In a fighting situation, control is required. Sometimes you must barely touch, sometimes you must strike to kill. If you strike too hard when the circumstances do not demand it, you may be held criminally or civilly liable. Patterns require precise control and mental discipline. Some think repeating the some combinations over and over makes one predictable. However, the combinations used in patterns, especially traditional forms, are not particularly useful in sparring or self-defense. Instead, they require one to use muscles and movements not generally used. This builds overall agility and strength. Although patterns require perfect technique and, if done properly, physical endurance, they are not primarily a physical exercise, they are a mental exercise. Just as in putting in golf, the balance beam in gymnastics, strikes in bowling, using English in billiards, and many other sporting endeavors, they show if the mind can maintain full, precise control of all body actions, while in a stressful situation.
Pattern movements have little to do with sparring or self-defense. No one in Taekwondo believes that it is possible to practice techniques in patterns that would cover the huge number of attacks available to opponents or assailants. The first patterns that were developed were based on actual combat techniques and were used to record them. Many techniques in modern patterns are there just for flash, some may be useful, but most are useless. Combat strategy is not to have a vast repertoire of techniques, but to perfect a few effective techniques. This is the same strategy used by good tournament fighters. Masters of old practiced one or two patterns until the techniques become instinctive. Now we have so many patterns to practice that their usefulness is diluted.
Many movements used against multiple attacks by one attacker or against simultaneous attacks by multiple attackers. The chances of an attacker attacking with more than one technique at the same locations required in a pattern movement are slim. The same holds true for multiple attackers simultaneously attacking the required locations.