The muscle spasms or cramps are usually called as idiopathic as no cause is ascertainable. Water and electrolytes derangement (potassium, magnesium, calcium), parathyroid and thyroid disorders, drugs are usual findings to be blamed. Water and electrolyte replenishment, stretching exercises are helpful. Read the resource;
Hope this helps you.
Your follow up questions are welcome.
Dear Laurence Kelly,
Though they commonly are not associated with any serious disorders, but with the intensity, frequency and your age, they warrant the investigations and subsequent management accordingly. A MRI of the spine can exclude the neurological causes for these muscle spasms. Myelography may be needed. Read here;
If your investigations are normal, you should consult a physiotherapist or physiatrist (specialist in physical medicine and rehabilitation) to learn stretching regime for the lower limbs. Doing them in the morning and before bed time will take care of the severity and frequency or may abate it all together. Meanwhile drinking plenty of fluids and water and electrolytes supplement should also help you.
Please feel free for your follow up questions.
Your physiatrist or orthopedist can consider giving you some medications like gabapentin. Apart from back, physical therapy regime should involve the lower limbs. The physiotherapy should only be stretching exercises. Some strengthening exercises or exercises with weight may not help you. One of the cause of muscle spasms is fatigue. So see, you are not working or doing exertion beyond the capacity.