Under stress, especially the stress of being attacked, your cognitive mind slows down as other parts of your brain take over. Your survival depends on how you have programmed yourself to react under stress. An attacker will be faster, stronger (as we have previously seen) and will take you by surprise.
The following points are what you need to use to explain your justification of having needed to use the amount of force you did. You are not only justified in using a higher amount of force, you will need to use a high level of force to survive an attack.
• Proximity to weapon
• Injury or exhaustion
• Hazardous environment
• Special knowledge
• Ground level
• Mental state
• Sometimes age
• Physical or mental disability
Self defense class for high school girls
Here is a typical example of teaching ineffectual strikes. I am not doing this to put anyone down, it's not my style. But at the same time it is a good visual of what I have been explaining.