What kind of strike should be used for the outside thigh area?

The use of an empty hand, leg, or knee strike to the outside thigh area is appropriate due to the sensitivity and vulnerability of that region. Striking with these parts allows for more control and adaptability in various situations, making it easier to target the muscle and cause discomfort or momentary incapacitation. This technique can also serve to disrupt an opponent's balance or mobility without delivering excessive force, which is critical in defensive tactics to minimize the risk of serious injury.

Moreover, using the leg or knee can provide a powerful, yet controlled impact, particularly when an opponent is close, making it effective for self-defense scenarios. Such strikes create an opportunity for further action or escape, emphasizing the objective of defensive tactics - to neutralize a threat while ensuring the safety of both the defender and the aggressor when necessary.