@Tiimmeeey but even if you can increase your stamina, since you still have a normal human condition your body won’t be able to withstand long fights or using your powers to enhance yourself
Regardless of superman not being human, what he said makes sense. Through the use of electricity in one’s body, the user can easily make themselves durable enough to at least sustain an enhanced level of speed, needless to say other things, too.
I chose Flight and Supernatural Condition. It’s easier for me to understand, less headaches. For combat, I suppose a sufficient amount of time set for training should do. If fighting becomes stressful, then optimizing my strength via flight to achieve record lifts should satisfy me.