Electric shocks are an incredibly visceral type of injury used commonly in the movies and often depicted in a faintly ridiculous manner. The portrayal of electrocution in films only compounds our general lack of understanding regarding precisely what's happening here, which is actually a much more complex process than you would probably expect. If you think that electricity 'travels through your body' then that's something of a myth for starters. Other aspects meanwhile like getting thrown across the room are actually real, but probably not for the reasons you think.
What Is a Current?
The first thing to understand when thinking about an electric shock is that nothing is going 'through' you. Many people visualise electricity as a substance like water that travels through the body during a shock, but this is actually inaccurate.
Rather, when we get electrocuted (which happens when we come into contact with a voltage of around 1 mA), it is actually the electrons in us that move, creating a 'current'. Imagine yourself as being an open ended tube of Smarties which is completely packed to the brim. If you push a Smartie in through the top, it's going to force one out of the other end – and this is precisely what happens when you have a current running through you (only with electrons, not Smarties).
As the current passes through your body, it will meet resistance in the form of your flesh (which acts the same way as a resistor in a circuit). Like a resistor though, this also creates heat, which is what causes the sometimes severe burns that you can receive from an electric shock.
It's also important to remember that electrical signals are what our bodies use to send signals between our nerves including muscle fibres and neurons. This then means that our nerves will register false positives, causing our muscles to flex for instance. When you watch someone get electrocuted in a film online, usually you will see that they get thrown across the room like a rag doll. The reason for this is actually that their own muscles are throwing them that far by tensing so suddenly. This is of interest to the world of strength training, because the power generated by the muscles appears to actually be greater than would normally be possible through the conscious decision to tense.
This is also how some of the very worst effects of electric shock occur. For instance, one of the most common causes of fatality is ventricular fibrillation – in other words current passing through the heart. If the current has a direct pathway through the heart this will commonly occur. Currents travelling from one arm to the other will often pass through the chest making these some of the most dangerous types of electric shock.
Neurological effects can also occur as a result of the electricity passing through the brain. This will result in loss of nervous control, usually resulting in swift loss of consciousness and ultimately death.
The precise effects and severity of electric shock will depend on the strength of the current as well as where it passes through the body. In every case though, this describes the basics of what's going on.
Conclusion? Don't stick your hand in sockets.