A staple of the JKD arsenal is the “stop kick,” jeet tek in Lee’s Cantonese. Although any kick that interrupts the initiation of an opponent’s attack is in the category of a stop kick, there are two variations referred to as jeet tek (JKD historians: feel free to chime in or correct me). Both are generally presented as “stiff leg” kicks, that is, there is no chambering, just picking the leg up and getting a stopping force on the opponent’s knee or shin (however you advance the kick). In one variation, the bottom of your foot is at a 45 degree angle to the surface you are contacting. The advantage of this variation is that there is no change of angle of the upper body to be seen by the opponent, it’s quite stealthy. Also, your upper body, having not turned, is quick to the follow up with hands. The second variation in its final position is that of a low side kick but still generally executed “stiff legged.” The advantage of this is that you can pump more force into it and your upper body is leaned back for better defense. In both cases, it is important to get a good contact with the arch of the foot rather than the ball. They are both very workable.
The one thing I would say is that your stance INCLUDES a chamber that is a shame to waste. That is, if using a slide and step to advance the kick, however bent your leg is in your stance, coordinate the straightening of the leg with the impact of your kick to get added force. Otherwise, it’s arguably like having your jab completely extended before contact rather than “hitting through” the target.