Increases in either strength or speed will increase power. Since it is possible to reach your maximum genetic speed and strength, further power gains will come about through the correct and efficient use of the muscles in karate technique. Strength is the maximum force that can be exerted in a single effort. Training for strength allows the muscles to become larger, thereby contracting more forcibly . Strength training will also strengthen the ligaments and tendons helping to prevent injury.
Speed is made up of reaction time and movement time.
Movement time is essentially inherited. Reaction time can be improved through training. Muscular endurance is the ability to repeatedly perform an action. Flexibility increases the range of options available controlling the range of motion of the body. Increased flexibility reduces energy required for performance and increases the range of options and tactics available.