Final answer:
Reaction time is the skill-related fitness component needed to be successful at ping pong and karate.
Step-by-step explanation:
The skill-related fitness component needed to be successful at ping pong and karate is reaction time. Reaction time is the ability to quickly respond to a stimulus. In ping pong, for example, a player needs to react quickly to the movement of the ball and make a shot. In karate, reaction time is important for counters and blocking techniques.