Random muscle twitches versus local twitch response (elicited from direct pressure)

Written By Bianca Ferraro

The difference between a random muscle twitch (e.g. on the leg or eye), and a twitch occurring when pressure is applied to a trigger point (Local twitch response via dry needling or compression):

What is a muscle twitch?
- A short muscle contraction that may be repetitive
- Typically not painful, but can be uncomfortable or become annoying
- Slight, small movement
- Happens most commonly in the upper leg and eyelid, and is most often harmless

Why do they happen?
- Stimulants such as caffeine
- Stress and anxiety (most common reason)
- Lack of magnesium and potassium, or other vitamins and minerals
- Fatigue

What is a muscle cramp?
- Prolonged and involuntary contraction that is typically painful
- Feels like the muscle is tightening
- Feel the need for urgent care to relax the muscle
- Sudden and lasts a few seconds to a few minutes
- The full muscle is involved and you temporarily can’t control/use it while it is cramping

Why do they happen?
- Lack of electrolytes
- Dehydration
- Stimulants such as caffeine
- Can be after too much exercise from toxins built up in the muscle (lack of oxygenated blood)
- Can occur at night time because of lifestyle during the day or a vitamin/mineral deficiency

Is there such thing as spasming?
When people refer to their muscle spasming, it can be often thought that a muscle is spasming/contracting around it to protect the area of sudden injury.
This is typically in response to their back being locked in a strong, painful contraction or cramp feeling and feels sore for a while afterwards, with an instant urge of needing treatment.
It is not to say the back is spasming, it is more of an indefinite description people use because of how it feels – as there is little to no evidence that supports a muscle to be able to spasm.

We must remember the way we describe our pain is a subjective sensation, so we can only use words such as tight, stiff, sharp, dull etc, as guidelines based off of how majority describe their pain in response to certain stimuli.

This can help explain lack of motion creating the sensation of stiffness due to the reluctancy of the brain to activate a muscle when we are injured  – and this is what most people may refer to as a body part spasming when you cannot move it after a sudden awkward movement - as it is very unlikely a muscle will contract if you have broken a bone because it is will cause further pain and damage.

Some theories for what is actually happening and why:
- A strong contraction occurring in the presence of pain/muscle dysfunction.
- When injuring yourself, the muscle goes into “lockdown” to make sure you don’t move your joint to cause more damage.
- Your body flinching away from something potentially dangerous or pain caused by a movement, causing a sudden contraction to get away from that danger which can feel like a “spasm”
- Not a “spasm” causing back pain, but rather back pain causing a reaction to clench and brace.

What is a local twitch response? And how is this different to a muscle twitching on its own without any pressure on a trigger point?

“A local twitch response is a spinal reflex which results from stimulation of a myofascial trigger point. This stimulation can be in the form of a digital pressure or irritation with a needle. When stimulated strongly enough, an action potential is transmitted along the motor nerve and creates a short-lived contraction (quick twitch) of some muscle fibres (usually the taut band) around or near-by the trigger point.
This short-lived contraction may be palpated or seen as a twitch in part of the muscle.

Myofascial dry needling (MDN) promotes an inflammatory response to a painful area of muscle (myofascial trigger point) that has remained contracted and filled with waste products, such as calcium.
This stimulates the body to replace calcium with magnesium allowing the area to relax (decreasing the myofascial trigger point).
When there is a local twitch response, it has an effect on the brain that alters the dorsal root ganglion and the brain (homunculus included).
After the myofascial trigger point has been treated, the muscle should report less pain, have some length restored, increased strength and improving facilitation (firing pattern)” (P. Atkinson 2007, updated by K.Sparre 2013 and Josh Davies 2014)

“Compression of a trigger point may elicit local tenderness, referred pain, or local twitch response. The local twitch response is not the same as a “spasm” or cramp. This is because a cramp refers to the entire muscle contracting whereas the local twitch response also refers to the entire muscle but only involves a small twitch, no contraction.”

Therefore, the differences in a local twitch response and a random twitch is: the reasons why it happens, the stimulus that causes the twitch, trigger points present, the changes to the brain and pain.

Does a local twitch response make it more successful?
Studies show you do not need a local twitch response in order for the treatment to be successful.

Bianca Ferraro
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