Human Electric Energy
The body is divided into specific electrical polarities or charges, most people understand the Positive Charges and the Negative Charges, not all realize there is also a grounding polarity. Mr.Gary Rooks discusses this openly in public seminars and classes, but let me explain the Seisan Kata in relation to these electrical charges for clarity and greater depth in your Kata.
Now a bit of this was demonstrated in https://kyusho.com/electrical-strike/ and of course covered in more detail in a linked podcast. But what it does is cause a feeling of electrical shock and when done well, a complete dysfunction of the motor skills causing the body to collapse.
The back of the Body is a negatively charged aspect, the Front is the Positive side (opposite of the TCM pressure Points and further proof that they are not the working mechanism in Kyusho), the sides are a neutral or ground.