An excellent way to increase strength and develop proper kicking form is to practice kicking very slowly – the slower you can do it, the harder it is.
One way to develop this, and the best way for newer students, is to put one hand on a wall and practice your slow kick – thus taking much of the balance difficulty out of the equation. The kick could be a snap kick, heal kick, turn kick, or side kick for starters…. hook kick, cutting kick, or others can also be practiced for more advanced students. Be sure to begin each kick by bringing up your knee first. Then, depending on what kick it is, fully extend your leg as slowly as possible and move your torso accordingly. As slowly as the kick went out, re-bend the knee and bring your torso back to an upright position. This takes a great deal of body control and strength – both from your leg muscles and core of your body.
To add even more difficulty, take your hand off the wall and do these kicks without supporting yourself. In addition to developing your ability to balance, this method requires even more strict attention to proper form. Just as when you’re balancing on the wall, you must initiate each kick by raising your knee first, extend the leg fully, re-bend the knee while bringing torso back to upright position, and step back into start position.
This method of training is relatively difficult for people to do, typically for less limber practitioners who struggle with balance. Start small by only doing a few kicks and keeping it at a speed that’s manageable. Remember that proper form is more important than anything else. Should you feel tightness in your hip or leg muscles, spend time stretching those muscles. After practicing for a few weeks, add more kicks or simply keep the same number of kicks only do them more slowly.
The ultimate end result of this practice is the ability to properly execute head height kicks and hold them at full extension without losing your balance. This requires a great deal of strength and flexibility, particularly in your legs and the benefits of this ability will certainly show in your sparring and forms. However, the ability to execute slow kicks with perfect form will translate into fast, sharp full speed kicks, which will prove quite useful in sparring.