Electricity can throw you back due to the effects of electric current on the human body. When electricity passes through the body, it stimulates muscles and nerves, causing involuntary muscle contractions that can make the body jerk or convulse. The strength of the electric shock determines how severely it throws you back.
What happens when electricity passes through the body?
When an electric current passes through the body, it flows through the tissues and muscles, overriding the body’s natural electrical signals. This disrupts the normal operation of the nervous system and muscles.
Specifically, electricity can cause the following effects:
- Stimulation of sensory nerves – This causes pain and heat sensations
- Stimulation of motor nerves – This causes involuntary muscle contractions
- Disruption of cardiac rhythm – Electricity can cause abnormal heart beats or cardiac arrest
- Damage to tissues – Electricity passing through tissues can cause burns and cell damage
The stimulation of sensory and motor nerves is what leads to the jerking movements and getting “thrown” by electricity. The strong muscle contractions make the body convulse in response to the electrical current.
Why do muscles contract when electrocuted?
Muscle contraction occurs when electricity depolarizes the muscle fibers. In biology, polarization refers to the difference in electric potential across a cell’s membrane. Muscles are normally polarized – maintaining a difference in charges across the membrane.
When electricity enters the body, it reduces this polarization. This opens up channels in the muscle fibers, allowing positive ions to flow across the membrane. The inflow of positive ions causes the muscle fibers to rapidly depolarize.
Depolarization triggers muscle contraction. The flooded positive ions initiate a chemical reaction that causes the overlapping protein filaments (actin and myosin) in muscle fibers to be pulled together. This makes the muscles shorten and contract involuntarily.
How strongly are you thrown back?
The strength of muscle contractions, and how far you get thrown back, depends on the voltage and amperage of the electric current flowing through the body:
- Higher voltage increases how much electricity can flow through the body. More current flow means more nerves and muscle fibers get stimulated, causing stronger contractions.
- Higher amperage means more electric charge is flowing per second. Greater current flow causes more severe muscle convulsions.
So high voltage and high amperage electrocution can violently stimulate a lot of muscles, making the body jerk and convulse with great force. On the other hand, a mild shock may only stimulate a few localized muscle groups.
Factors that influence effects of electric shock
Several factors determine the exact effects of an electric shock on the human body:
- Pathway through body – The path the current takes through the tissues affects which nerves and muscles get stimulated. For example, current across the chest is more likely to cause cardiac arrest.
- Duration of contact – Longer contact with an energized object allows more current to flow through the body and cause greater effects.
- Skin moisture – Dry intact skin has higher resistance. Sweaty or wet skin allows electricity to pass through the body more easily.
- Health conditions – Weakened heart or other illnesses can increase risk of death from smaller amounts of current.
Types of electrical injuries
Electrical injuries are commonly classified into four types:
| Type | Cause | Effects |
|---|---|---|
| Direct contact injuries | Touching exposed energized conductors | Severe muscle contractions and nerve stimulation effects |
| Arc flash injuries | Exposure to high temp plasma arc | Severe burns |
| Ground injuries | Electricity passes through body to ground | Deep muscle and nerve damage along current path |
| Static injuries | Build up of static charge on body | Painful spark discharge that may cause involuntary motion |
Direct contact with energized objects causes the most violent convulsions and person being thrown backwards. The other types may cause motion from muscle contractions, but less severely.
Factors that determine how far you are thrown
The distance you get thrown backwards depends on the intensity of muscle contractions and these key factors:
- Body stance – If body is off-balance, it is easier to get knocked down and thrown farther by muscle jerks.
- Point of contact – If contact is made with an outstretched arm, the limb gets jerked back more violently than the rest of body.
- Surroundings – Hitting objects or walls nearby can limit how far you get thrown.
- Moisture – Wet conditions reduce body resistance and allow more current flow, causing stronger contractions.
In open surroundings with the body off-balance, severe high voltage electrocution can throw an adult over 10 feet backwards. But near objects or walls may limit this distance.
Mechanism of specific motion patterns
The electric current pathway through the body determines the pattern of muscle stimulation, producing these common types of motions:
Hand to hand
Current across the chest from hand to hand stimulates chest and arm muscles, jerking the arms away and arching the back.
Hand to foot
Current from a hand to a foot stimulates one side of the body more than the other. This pulls the limbs on that side inwards and throws the person sideways or in a spinning motion.
Through the head
Current through the head region stimulates the nerves and muscles of the neck and back forcefully. This often violently jerks the head back and arches the spine.
Limb to limb
If current passes between two limbs (e.g. hand to foot), it stimulates the muscles in that region. This pulls the two limbs together, sometimes making the person hug themselves.
Can you let go once electrocuted?
It is very difficult, often impossible, for a person to voluntarily let go of an energized object once initially gripped. The involuntary muscle contractions prevent relaxing the grip.
However, at a certain point the sustained muscle contractions can cause neuromuscular fatigue. The overstimulated muscles get exhausted trying to contract continuously. This fatigue allows the convulsing limbs to get flung away from the electric source.
The sustained grip from electrocution is due to stimulation of finger flexor muscles more than hand relaxation muscles. Trying to consciously relax the hand is very difficult when large motor units are firing at maximum contraction.
First aid for electric shock victims
If you witness someone being electrocuted, immediately power off the electric source if possible. Call emergency services once the person is free from contact. Avoid directly touching the person while they are still in contact with electricity to prevent being shocked yourself.
After discontinuing electrical contact, begin first aid:
- Assess breathing. Give rescue breaths if not breathing. Doing chest compressions if there is no pulse.
- Check for burns or other injuries. Treat severe bleeding and cover burns.
- Keep them still and calm. Prevent further injury until paramedics arrive.
- Monitor vital signs. Be prepared to provide CPR if breathing or pulse stops.
Electric shock victims should be evaluated by medical professionals even if they appear normal. Internal injuries may not be immediately obvious.
Preventing electrical injuries
These safety practices can help prevent being thrown or injured by electricity:
- Assume all overhead wires are energized. Keep at least 10 feet distance.
- Ensure all electrical tools and equipment are properly grounded. Use GFCIs.
- Never use electrical devices when you, the device, or the surroundings are wet.
- Do not touch anyone being shocked – power off electricity first.
- Check for frayed cords and other damage before using devices. Don’t overload outlets.
- Keep outdoor outlets protected from moisture. Use weatherproof gear for outdoor use.
Conclusion
In summary, electricity throws you back due to forceful stimulation of sensory and motor nerves that trigger involuntary muscle contractions. Higher voltage and amperage leads to more violent convulsions that can throw the body farther. Immediate first aid and preventing exposure are key for avoiding or responding to electrical injuries.