Superhuman strength, also called hysterical strength, refers to extraordinary displays of human strength. This is typically prompted by a life-threatening situation, like when a parent lifting up a vehicle to save a trapped child.

This is believed to be caused the body’s stress response, which triggers a rush of the hormone adrenaline.

Is superhuman strength real? It probably is. There are numerous news reports that suggest the veracity of the phenomenon. Superhuman strength isn’t just a theory; there’s likely some truth to this.

Scientists have only a tentative understanding of what exactly might be behind hysterical strength, but here are the probable causes of superhuman strength:

Physical potential

We use only a fraction of our maximum theoretical strength as our bodies tend to conserve energy when possible. Estimates vary, but research reveals that the amount of muscle mass used during maximal exercise is around 60 percent. Even elite athletes only harness around 80 percent of their theoretical strength. Why? Our body is protecting us from injury. If we go beyond our absolute maximum, we could tear our muscle tissue, ligaments, tendons and/ or break our bones.

The fight-or-flight response

For us to understand superhuman strength, we must understand the body’s response to stress: fight-or-flight response.

The flight-or-fight response is the automatic physiological reaction to an event that is perceived as stressful or frightening. When we are threatened, our body triggers a complex physiological response:

The response starts in our amygdala, the part of our brain that’s associated with fear. The amygdala activates the hypothalamus, which releases stress hormones like adrenaline and cortisol.

The hormone adrenaline makes our heart and lungs work faster. This sends more oxygen to your major muscles, which gives us temporary boost of strength. Our vision and hearing are also heightened, which helps us remain alert and focused.

The hormone cortisol, on the other hand, helps us access stores of glucose (sugar) in our body, giving us extra energy for sustained effort.

Another hormone that our body releases is the endorphins, or the feel-good chemicals. They help reduce our perception of pain. This means that what might be usually feel painful to us will hurt less.

These are just a few of the physiological changes that can help explain why our strength increases when we are responding to a stressor.

Physical conditioning

Research on athletic performance can also shed light of this phenomenon. In athletes, there are factors that affect adrenaline levels. These are sex, age, nutrition, arousal, and mood.

Also, adrenaline levels seems higher among athletes that have undergone endurance training. This is why elite athletes can increase their strength when it’s time to perform.

 

Can we tap then into our additional strength when we need it? There are certain limitations since it is difficult to actually pinpoint how much our fight-or-flight response can actually boosts strength. Another factor is our body mass, which limits how much we are capable of doing. So a person with no previous weight training would not suddenly be able to lift a car.

Obviously, we are capable of more than we realize. Our true capacity may emerge when the stakes are high. But then again, it may not.