This blog will cover two of the most common questions I’m asked: “What is a muscle knot?” and “Why do we get cramp?“
Muscle knots, technically known as trigger points, are hard nodules in a taut band of muscle. They are palpable, tender bumps under the skin often the size of your thumb.
They can be classified into two groups – active and latent.
An active trigger point is associated with pain in the immediate and surrounding area and may also refer the pain to a site distant from the trigger point. For example a trigger point in the shoulder can refer pain down the arm. Pressure to the active trigger point exacerbates the pain and can cause a twitch response.
A latent trigger point causes pain local to the site of the nodule but does not refer pain. The pain experienced is only felt when pressure is applied, unlike an active trigger point which can cause pain even without pressure.
Both latent and active trigger points can be associated with muscle dysfunction, muscle weakness, and a limited range of motion.
But what are they?
A trigger point is a localised area of hyperirritability within a muscle. A small patch of muscle fibres tightly contracts, even when the muscle is at rest, creating an area of localised tension.
Trigger points can develop following injury or as a result of muscle overuse. Muscle overuse is common in low-intensity daily activities such as sedentary work.
Sitting at a desk all day requires sustained low level contractions of the neck and shoulder muscles resulting in continuous activation and metabolic overload of some muscle fibres. This contraction constricts the capillaries, reducing blood flow and therefore supply of oxygen and nutrients. Energy production is then compromised and the chemical balance of the cells is unsettled. Cell signalling is disrupted with an increase in production of the neurotransmitter acetylcholine which signals to the muscle fibers to contract. This is the beginning of a vicious cycle causing persistent contracture ‘knots’ or trigger points.
What can be done about trigger points?
Osteopathy, sports massage, rest, hot and cold therapy, stretches and exercise can all help trigger points by releasing tension and increasing blood flow and nutrients to improve tone and health of the muscle.
Assessment of posture, alignment and movement of the nearby joints will identify any areas of structural imbalance. Stretches, mobilisations and manipulations to the relevant areas will improve flexibility and quality of movement, reducing any excess strain on the muscles.
- Soft Tissue Massage
Massage techniques to the trigger point and surrounding muscles will reduce muscle tension and encourage blood flow to the area delivering oxygen and nutrients to normalise the cells chemical balance.
Sedentary work at a computer often results in the front shoulder muscles becoming extremely tight and the back shoulder muscles strained. Stretching the overworked muscles and strengthening the area will help to resolve any muscular imbalances.
Make sure you warm up and cool down each time you exercise and try to avoid sitting for long periods.
- Hot and Cold Therapy
Applying a heat pack causes the blood vessels to dilate (widen) encouraging more blood flow to the trigger point and also helps to relieve tension in the muscle.
A cold pack can help numb the area, reducing any pain associated with the trigger point, although cold packs have the opposite effect on blood flow causing the blood vessels to constrict (narrow).
However, alternating between the two (apply heat for 5 minutes, rest 3 minutes, then ice for 5 minutes and repeat this process 3 times) will create a flushing effect on the blood flow to the trigger point, encouraging the healing process.
Muscle cramp is a sudden involuntary contraction of the whole muscle (as opposed to a small group of muscle fibres for trigger points).
Muscle cramps are often very painful with a quick onset, lasting seconds to minutes. They most commonly occur in the calf at night time.
There can be many causes of muscle cramps but for many people their cramps have no known cause.
Dehydration, muscle strains and overuse can cause cramps. There are also many underlying medical conditions that can cause cramps and I have outlined common examples below:
Narrowing of the arteries from the build up of fatty plaques results in reduced blood flow to the legs causing cramps in the calves, particularly with the onset of exercise. These cramps quickly resolve with the cessation of exercise.
Spinal Nerve Compression
A disc bulge can compress a spinal nerve root causing cramping sensations in the affected muscles supplied by that nerve. This is also known as sciatica, for which there are many things I can do to help (click here for more info).
There are also situations where the whole of the spinal cord can become compressed disrupting the nerve signals to the lower limbs causing cramps. People suffering from this will often find that bending forward (such as walking up hill or pushing a shopping trolley) reduces their symptoms. Treatment of this will vary depending on the cause of the spinal compression.
An underactive thyroid (hypothyroidism) can cause muscle cramps. These should be controlled by thyroid medication.
Low potassium, calcium and magnesium can also cause cramps. These mineral deficiencies are common side effects of medications, particularly those used for high blood pressure.
What to do if you get cramps?
If a cramp does start you can ease it by gently easing the muscle into a stretch. If you suffer from regular cramps it is important to consult your GP who will check for any underlying medical conditions.