The Phenomenon of Superhuman Strength
In moments of extreme mortal danger, humans can temporarily tap into reserves of strength far beyond their normal physical capacity. This surge allows people to lift heavy objects like cars to save others.
This phenomenon occurs when the brain releases massive amounts of adrenaline, temporarily overriding the body's natural safety limits. Usually, our nervous system holds back muscle power to prevent self-injury, but survival instincts can override these inhibitors. While most reports are based on personal accounts, the science suggests our bodies possess latent power that is normally locked away. This proves that human physical potential is often limited more by the brain than by muscle.
Source: Hysterical strength